Microparticles

Abstract Recent measurements of snow accumulation on undulating surfaces around “Byrd station”, Antarctica indicate that the undulations are tending to be filled in. These results are discussed in the light of current knowledge of the origin and migration of such features.

@article{doi101017s0022143000018906,
    author = "Gow, Anthony J. and Rowland, Robert W.",
    title = "On the Relationship of Snow Accumulation to Surface Topography at “Byrd Station”, Antarctica",
    year = "1965",
    journal = "Journal of Glaciology",
    abstract = "Abstract Recent measurements of snow accumulation on undulating surfaces around “Byrd station”, Antarctica indicate that the undulations are tending to be filled in. These results are discussed in the light of current knowledge of the origin and migration of such features.",
    url = "https://doi.org/10.1017/s0022143000018906",
    doi = "10.1017/s0022143000018906",
    openalex = "W2468832152"
}

Oxygen- and hydrogen-isotope analyses from the core hole through the Antarctic Ice Sheet at Byrd Station define temperature variations over more than 75,000 years. Synchronism between major climatic changes in Antarctica and the Northern Hemisphere is strongly indicated. The Wisconsin cold interval extended from 75,000 to 11,000 years ago. Three intra-Wisconsin warmer phases were all colder than pre- or post-Wisconsin times, which suggests that North American and Eurasian continental ice sheets did not disappear at any time during the Wisconsin.

@article{epstein1970antarctic,
    author = "Epstein, Samuel and Sharp, R. P. and Gow, A. J.",
    title = "Antarctic Ice Sheet: Stable Isotope Analyses of Byrd Station Cores and Interhemispheric Climatic Implications",
    year = "1970",
    journal = "Science",
    abstract = "Oxygen- and hydrogen-isotope analyses from the core hole through the Antarctic Ice Sheet at Byrd Station define temperature variations over more than 75,000 years. Synchronism between major climatic changes in Antarctica and the Northern Hemisphere is strongly indicated. The Wisconsin cold interval extended from 75,000 to 11,000 years ago. Three intra-Wisconsin warmer phases were all colder than pre- or post-Wisconsin times, which suggests that North American and Eurasian continental ice sheets did not disappear at any time during the Wisconsin.",
    url = "https://doi.org/10.1126/science.168.3939.1570",
    doi = "10.1126/science.168.3939.1570",
    number = "3939",
    openalex = "W2044683518",
    pages = "1570-1572",
    volume = "168",
    references = "doi1010160016703753900519, doi101017s0022143000028367, doi101017s0022143000031208, doi101029jb073i008p02691, doi101086627150, doi101126science1253240182, doi101126science16138451011, doi1023071796130, doi103189s0022143000028367, doi103189s0022143000031208"
}

@incollection{gow1973climatological,
    author = "Gow, Anthony J. and Epstein, Samuel and Sharp, Robert P.",
    title = "Climatological Implications of Stable Isotope Variations in Deep Ice Cores from Byrd Station, Antarctica",
    year = "1973",
    booktitle = "Geological Society of America Memoirs",
    url = "https://doi.org/10.1130/mem136-p323",
    doi = "10.1130/mem136-p323",
    openalex = "W2345931003",
    pages = "323-326"
}

The concentration of microparticles in the 216 4 m long ice core from “Byrd” station Antarctica, varies cyclically. Highest concentrations of 0.65 μm diameter microparticles occur where oxygen-isotope studies show lowest paleotemperatures. The age of the bottom ice estimated from microparticle-concentration variations, assuming an annual cycle, is 27 000 years, much less than from oxygen-isotope studies.

@article{doi101017s0022143000021948,
    author = "Thompson, Lonnie G. and Hamilton, Wayne L. and Bull, C.",
    title = "Climatological, Implications of Microparticle Concentrations in the Ice Core From “Byrd” Station, Western Antarctica",
    year = "1975",
    journal = "Journal of Glaciology",
    abstract = "The concentration of microparticles in the 216 4 m long ice core from “Byrd” station Antarctica, varies cyclically. Highest concentrations of 0.65 μm diameter microparticles occur where oxygen-isotope studies show lowest paleotemperatures. The age of the bottom ice estimated from microparticle-concentration variations, assuming an annual cycle, is 27 000 years, much less than from oxygen-isotope studies.",
    url = "https://doi.org/10.1017/s0022143000021948",
    doi = "10.1017/s0022143000021948",
    openalex = "W4241017141",
    references = "doi1010160012821x67900623, doi1010160012821x71901269, doi101017s0022143000013423, doi101017s0022143000027386, doi101038235429a0, doi101098rsta19700010, doi101126science16138451011, doi101126science1663903377, doi101126science1733992138, epstein1970antarctic"
}

The concentration of microparticles in the 2 164 m long ice core from “Byrd” station Antarctica, varies cyclically. Highest concentrations of 0.65 μm diameter microparticles occur where oxygen-isotope studies show lowest paleotemperatures. The age of the bottom ice estimated from microparticle-concentration variations, assuming an annual cycle, is 27 000 years, much less than from oxygen-isotope studies.

@article{thompson1975climatological,
    author = "Thompson, Lonnie G. and Hamilton, Wayne L. and Bull, Colin",
    title = "Climatological, Implications of Microparticle Concentrations in the Ice Core From “Byrd” Station, Western Antarctica",
    year = "1975",
    journal = "Journal of Glaciology",
    abstract = "The concentration of microparticles in the 2 164 m long ice core from “Byrd” station Antarctica, varies cyclically. Highest concentrations of 0.65 μm diameter microparticles occur where oxygen-isotope studies show lowest paleotemperatures. The age of the bottom ice estimated from microparticle-concentration variations, assuming an annual cycle, is 27 000 years, much less than from oxygen-isotope studies.",
    url = "https://doi.org/10.3189/s0022143000021948",
    doi = "10.3189/s0022143000021948",
    number = "72",
    openalex = "W2586674038",
    pages = "433-444",
    volume = "14",
    references = "doi1010160012821x71901269, doi101016s0074614208x60450, doi101017s0022143000027386, doi101038235429a0, doi101098rsta19700010, doi101126science16138451011, doi101126science1663903377, doi101126science1733992138, doi1011751520046919620190474nisaic20co2, epstein1970antarctic"
}

@article{thompson1975climatological2,
    author = "Thompson, L. G. and Hamilton, W. L. and Bull, C",
    title = {Climatological implications of microparticle concentrations in the ice core from "Byrd" Station, western Antarctica},
    year = "1975",
    journal = "Journal of Glaciology, v. 14, p. 433-444",
    note = {talkorigins\_source = {true}; raw\_reference = {Thompson, L. G., Hamilton, W. L., and Bull, C., 1975, Climatological implications of microparticle concentrations in the ice core from "Byrd" Station, western Antarctica: Journal of Glaciology, v. 14, p. 433-444.}}
}

In a recent paper in the Journal (Thompson and others, 1975) a new time scale along the "Byrd" station ice core is suggested.It is based on the interpretation of varying microparticle concentration in terms of seasonal variations, which leads to the conclusion that the age of the bottom ice is only 27 000 years.We agree with several of the viewpoints put forward in the paper, for example that identification of annual layers by microparticle variations may push the limit for absolute dating of polar ice cores much farther back in time than that set by diffusive obliteration of seasonal stable-isotope cycles.However, it is extremely difficult to accept the interpretation and the consequent conclusion of Thompson and others (1975), mainly for the following reasons:

@article{doi101017s0022143000013666,
    author = "Johnsen, S. J. and Hammer, C. U. and Reeh, Niels and Dansgaard, W.",
    title = "Microparticles in “Byrd” station ice core: comments on the paper by L. G. Thompson, W. L. Hamilton and C. Bull",
    year = "1976",
    journal = "Journal of Glaciology",
    abstract = {In a recent paper in the Journal (Thompson and others, 1975) a new time scale along the "Byrd" station ice core is suggested.It is based on the interpretation of varying microparticle concentration in terms of seasonal variations, which leads to the conclusion that the age of the bottom ice is only 27 000 years.We agree with several of the viewpoints put forward in the paper, for example that identification of annual layers by microparticle variations may push the limit for absolute dating of polar ice cores much farther back in time than that set by diffusive obliteration of seasonal stable-isotope cycles.However, it is extremely difficult to accept the interpretation and the consequent conclusion of Thompson and others (1975), mainly for the following reasons:},
    url = "https://doi.org/10.1017/s0022143000013666",
    doi = "10.1017/s0022143000013666",
    openalex = "W2587731250"
}

Abstract The continuity relationship that is often used in the study of ice sheets and ice shelves is developed by integrating the equation of continuity through the ice thickness. This equation is then integrated again with respect to horizontal distance from an ice divide, showing that the difference between the true ice velocity and the balance velocity, which is defined, is a measure of the time chance of the mass of a column through the ice thickness. The relationship is applied using data from along the “Byrd” station strain network, Antarctica. This region is found to be thinning slowly (0.03 m a −1 of ice of mean density) and uniformly, but it is still close to steady-state. The calculations would show a larger thinning rate if bottom sliding contributed more to the ice movement and integral shear contributed less, but the “Byrd” station bore-hole tilting results of Garfield and Ueda (1975, 1976), together with surface velocity measurements at “Byrd” station, indicate that most of the ice flow is by deformation within the ice mass. This large amount of internal deformation is more than that predicted by most “flow laws”, probably because of the strongly oriented ice-crystal fabric in the ice sheet. The cause of ice thinning is probably decreased surface mass balance beginning before A.D. 1550. The consistent relationship between measured velocity and balance velocity indicates that the ice flow is simple and that flow lines are in the same direction at depth as at the surface when considered smoothed over a distance of 10 km. Because the ice sheet is at present thinning, the balance velocity, calculated only from flow line and surface mass-balance data, and the somewhat mistaken assumption of steady-state is 15% less than the true ice velocity. This rather small difference confirms the use of balance-velocity estimates where velocity measurements are not available.

@article{doi101017s0022143000021055,
    author = "Whillans, I. M.",
    title = "The Equation of Continuity and its Application to the Ice Sheet Near “byrd” Station, Antarctica",
    year = "1977",
    journal = "Journal of Glaciology",
    abstract = "Abstract The continuity relationship that is often used in the study of ice sheets and ice shelves is developed by integrating the equation of continuity through the ice thickness. This equation is then integrated again with respect to horizontal distance from an ice divide, showing that the difference between the true ice velocity and the balance velocity, which is defined, is a measure of the time chance of the mass of a column through the ice thickness. The relationship is applied using data from along the “Byrd” station strain network, Antarctica. This region is found to be thinning slowly (0.03 m a −1 of ice of mean density) and uniformly, but it is still close to steady-state. The calculations would show a larger thinning rate if bottom sliding contributed more to the ice movement and integral shear contributed less, but the “Byrd” station bore-hole tilting results of Garfield and Ueda (1975, 1976), together with surface velocity measurements at “Byrd” station, indicate that most of the ice flow is by deformation within the ice mass. This large amount of internal deformation is more than that predicted by most “flow laws”, probably because of the strongly oriented ice-crystal fabric in the ice sheet. The cause of ice thinning is probably decreased surface mass balance beginning before A.D. 1550. The consistent relationship between measured velocity and balance velocity indicates that the ice flow is simple and that flow lines are in the same direction at depth as at the surface when considered smoothed over a distance of 10 km. Because the ice sheet is at present thinning, the balance velocity, calculated only from flow line and surface mass-balance data, and the somewhat mistaken assumption of steady-state is 15\% less than the true ice velocity. This rather small difference confirms the use of balance-velocity estimates where velocity measurements are not available.",
    url = "https://doi.org/10.1017/s0022143000021055",
    doi = "10.1017/s0022143000021055",
    openalex = "W2586602957",
    references = "gow1973climatological"
}

We greatly appreciate the interest shown by Johnsen

@article{doi101017s0022143000021687,
    author = "Thompson, Lonnie G. and Hamilton, Wayne L. and Bull, C.",
    title = "Microparticles in “Byrd” station ice core: reply to comments by S. J. Johnsen, C. U. Hammer, N. Reeh and W. Dansgaard",
    year = "1977",
    journal = "Journal of Glaciology",
    abstract = "We greatly appreciate the interest shown by Johnsen",
    url = "https://doi.org/10.1017/s0022143000021687",
    doi = "10.1017/s0022143000021687",
    openalex = "W2586815264"
}

Once again, we agree with some of the viewpoints put forward by Thompson and others (1977).For example, we agree that the ice flow in the "Byrd" area must be of quite unusual character if the layer thicknesses claimed were true.Also we agree that detection of seasonal variations in the microparticle concentration in an ice core is not just a matter of increasing the sampling frequ ency.The appropriate sampling frequ ency must in any given case depend upon the signal-to-noise ratio.Using the minimum of 3 or 4 samples per annual layer is justified only in high accumulation areas with particularly favourable wind, fall-out and d eposition conditions.In our opinion, the authors' new figure I (above) suggests that this does not hold true for the "Byrd" area.In fact, it stresses the authors' statement that "conclusive proof is lacking that the short-period variations in micropartide concentration are annual".We feel this problem should b e solved prior to discussing flow patterns or time scales based on any interpretation of dust profiles.It is true that there is some degree of similarity between the dust and 8(IB O) variations in (according to Johnsen and others, 1972) a 15500 year old increm ent (Thompson and others, 1975, fig.I), but it is difficult to accept as "strong presumptive evidence", because the 8 oscillation is short and obviously atypical, while the dust profile is disturbed by numerous volcanic ash bands.Furthermore, Marshall (1962) suggested seasonal dust variations at 2 I m d epth, but he analysed only 0.65 m of firn comprising two annual layers as determined by visual stratigraphy observations.And, tru e enough, if seasonal dust variations are recognizable at Pole of Relative Inaccessibility, they may also b e so at "Byrd" that has twice as much accumulation; on the other hand, the meteorological regimes at the two stations are quite different, and midway between them, at the South Pole, "there are difficulties in determining the annual layering" (Thompson and others, 1975), may be because the fall-out in this area (and at "Byrd"?) simply does not vary r egularly with the seasons in an interpretable way.H ence, we consider a feasibility study as particularly important in areas like "Byrd", closer to active volcanoes than to potential sources of continental dust.Marshall's excellent pilot study should be followed up by measuring a detailed dust-concentration profile through th e upper firn from the surface down to strata that can b e safely dated, e.g. by identification of total ~-activity reference horizons.This is undoubtedly what Thompson and others (1975) have in mind, when stating on p. 441: "In the 1973-74 Antarctic field season one of us (L.C.T.) collected samples for microparticle analysis from areas near 'Byrd' station where the snow stratigraphy and chronology are well known".In several respects these analyses will render much more information than the new figure I above.Finally, a short remark about matching the Camp Century and "Byrd" time scales.The technique used by Johnsen and others (1972) essentially implied the assumption that the Wisconsin glaciation began and ended almost simultaneously in the two hemispheres.The uncertainty on this point is one of the reasons why we are ourselves not satisfied with our "Byrd" time scale.We sincerely hope that Thompson and his co-workers will succeed in proving the applicability of the microparticle dating method at "Byrd", the more so as the range of the 14C ice-dating method does not exceed 25 000 years.

@article{doi101017s0022143000021699,
    author = "Johnsen, S. J. and Hammer, C. U. and Reeh, Niels and Dansgaard, W.",
    title = "Microparticles in “Byrd” station ice core: further comments on the paper by L. G. Thompson, W. L. Hamilton and C. Bull",
    year = "1977",
    journal = "Journal of Glaciology",
    abstract = {Once again, we agree with some of the viewpoints put forward by Thompson and others (1977).For example, we agree that the ice flow in the "Byrd" area must be of quite unusual character if the layer thicknesses claimed were true.Also we agree that detection of seasonal variations in the microparticle concentration in an ice core is not just a matter of increasing the sampling frequ ency.The appropriate sampling frequ ency must in any given case depend upon the signal-to-noise ratio.Using the minimum of 3 or 4 samples per annual layer is justified only in high accumulation areas with particularly favourable wind, fall-out and d eposition conditions.In our opinion, the authors' new figure I (above) suggests that this does not hold true for the "Byrd" area.In fact, it stresses the authors' statement that "conclusive proof is lacking that the short-period variations in micropartide concentration are annual".We feel this problem should b e solved prior to discussing flow patterns or time scales based on any interpretation of dust profiles.It is true that there is some degree of similarity between the dust and 8(IB O) variations in (according to Johnsen and others, 1972) a 15500 year old increm ent (Thompson and others, 1975, fig.I), but it is difficult to accept as "strong presumptive evidence", because the 8 oscillation is short and obviously atypical, while the dust profile is disturbed by numerous volcanic ash bands.Furthermore, Marshall (1962) suggested seasonal dust variations at 2 I m d epth, but he analysed only 0.65 m of firn comprising two annual layers as determined by visual stratigraphy observations.And, tru e enough, if seasonal dust variations are recognizable at Pole of Relative Inaccessibility, they may also b e so at "Byrd" that has twice as much accumulation; on the other hand, the meteorological regimes at the two stations are quite different, and midway between them, at the South Pole, "there are difficulties in determining the annual layering" (Thompson and others, 1975), may be because the fall-out in this area (and at "Byrd"?) simply does not vary r egularly with the seasons in an interpretable way.H ence, we consider a feasibility study as particularly important in areas like "Byrd", closer to active volcanoes than to potential sources of continental dust.Marshall's excellent pilot study should be followed up by measuring a detailed dust-concentration profile through th e upper firn from the surface down to strata that can b e safely dated, e.g. by identification of total \textasciitilde -activity reference horizons.This is undoubtedly what Thompson and others (1975) have in mind, when stating on p. 441: "In the 1973-74 Antarctic field season one of us (L.C.T.) collected samples for microparticle analysis from areas near 'Byrd' station where the snow stratigraphy and chronology are well known".In several respects these analyses will render much more information than the new figure I above.Finally, a short remark about matching the Camp Century and "Byrd" time scales.The technique used by Johnsen and others (1972) essentially implied the assumption that the Wisconsin glaciation began and ended almost simultaneously in the two hemispheres.The uncertainty on this point is one of the reasons why we are ourselves not satisfied with our "Byrd" time scale.We sincerely hope that Thompson and his co-workers will succeed in proving the applicability of the microparticle dating method at "Byrd", the more so as the range of the 14C ice-dating method does not exceed 25 000 years.},
    url = "https://doi.org/10.1017/s0022143000021699",
    doi = "10.1017/s0022143000021699",
    openalex = "W4247676142"
}

Abstract The local variability in surface mass balance (net snow accumulation) up-glacier from "Byrd" station, Antarctica, is due to the combined effects of year-to-year "climate" variations and of the surface microrelief clue to snow drifts and sastrugi. These variabilities are consistent with the variability in surface mass balance obtained from core stratigraphy (Gow, 1968), and are used in a discussion of the difficulties encountered with the deep "Byrd" station core in detecting annual layering by the stable oxygen-isotope ratio and the microparticle concentration techniques. The recognition of annual layers by these techniques requires that the snows of certain seasons be present in the measured section, but near "Byrd" station the microrclief is such that summer snow layers are not horizontally continuous and may be absent from a given section. At other sites on ice sheets, where the microrelief is less (less wind activity) or where the surface mass balance is larger, or both, less difficulty is anticipated in using the stable oxygen-isotope ratio and micro-particle-concentration techniques to identify annual layers.

@article{doi101017s002214300001385x,
    author = "Whillans, I. M.",
    title = "Surface Mass-Balance Variability Near “Byrd” Station, Antarctica, and its Importance to Ice Core Stratigraphy",
    year = "1978",
    journal = "Journal of Glaciology",
    abstract = {Abstract The local variability in surface mass balance (net snow accumulation) up-glacier from "Byrd" station, Antarctica, is due to the combined effects of year-to-year "climate" variations and of the surface microrelief clue to snow drifts and sastrugi. These variabilities are consistent with the variability in surface mass balance obtained from core stratigraphy (Gow, 1968), and are used in a discussion of the difficulties encountered with the deep "Byrd" station core in detecting annual layering by the stable oxygen-isotope ratio and the microparticle concentration techniques. The recognition of annual layers by these techniques requires that the snows of certain seasons be present in the measured section, but near "Byrd" station the microrclief is such that summer snow layers are not horizontally continuous and may be absent from a given section. At other sites on ice sheets, where the microrelief is less (less wind activity) or where the surface mass balance is larger, or both, less difficulty is anticipated in using the stable oxygen-isotope ratio and micro-particle-concentration techniques to identify annual layers.},
    url = "https://doi.org/10.1017/s002214300001385x",
    doi = "10.1017/s002214300001385x",
    openalex = "W2587534313",
    references = "doi101017s0022143000013423, doi101017s002214300001844x, doi101017s0022143000020530, doi101017s0022143000021948, doi101029ar002p0127, doi101029ar016p0333, doi101029jz067i013p05163, doi1023071796130, doi103189s0022143000020530, gow1973climatological, thompson1975climatological"
}

Abstract The local variability in surface mass balance (net snow accumulation) up-glacier from "Byrd" station, Antarctica, is due to the combined effects of year-to-year "climate" variations and of the surface microrelief clue to snow drifts and sastrugi. These variabilities are consistent with the variability in surface mass balance obtained from core stratigraphy (Gow, 1968), and are used in a discussion of the difficulties encountered with the deep "Byrd" station core in detecting annual layering by the stable oxygen-isotope ratio and the microparticle concentration techniques. The recognition of annual layers by these techniques requires that the snows of certain seasons be present in the measured section, but near "Byrd" station the microrclief is such that summer snow layers are not horizontally continuous and may be absent from a given section. At other sites on ice sheets, where the microrelief is less (less wind activity) or where the surface mass balance is larger, or both, less difficulty is anticipated in using the stable oxygen-isotope ratio and micro-particle-concentration techniques to identify annual layers.

@article{doi103189s002214300001385x,
    author = "Whillans, I. M.",
    title = "Surface Mass-Balance Variability Near “Byrd” Station, Antarctica, and its Importance to Ice Core Stratigraphy",
    year = "1978",
    journal = "Journal of Glaciology",
    abstract = {Abstract The local variability in surface mass balance (net snow accumulation) up-glacier from "Byrd" station, Antarctica, is due to the combined effects of year-to-year "climate" variations and of the surface microrelief clue to snow drifts and sastrugi. These variabilities are consistent with the variability in surface mass balance obtained from core stratigraphy (Gow, 1968), and are used in a discussion of the difficulties encountered with the deep "Byrd" station core in detecting annual layering by the stable oxygen-isotope ratio and the microparticle concentration techniques. The recognition of annual layers by these techniques requires that the snows of certain seasons be present in the measured section, but near "Byrd" station the microrclief is such that summer snow layers are not horizontally continuous and may be absent from a given section. At other sites on ice sheets, where the microrelief is less (less wind activity) or where the surface mass balance is larger, or both, less difficulty is anticipated in using the stable oxygen-isotope ratio and micro-particle-concentration techniques to identify annual layers.},
    url = "https://doi.org/10.3189/s002214300001385x",
    doi = "10.3189/s002214300001385x",
    openalex = "W4242269813",
    references = "doi101017s0022143000020530"
}

@article{kyle1978compositions,
    author = "Kyle, Philip R. and Jezek, Peter A.",
    title = "Compositions of three tephra layers from the byrd station ice core, antarctica",
    year = "1978",
    journal = "Journal of Volcanology and Geothermal Research",
    url = "https://doi.org/10.1016/0377-0273(78)90014-8",
    doi = "10.1016/0377-0273(78)90014-8",
    number = "3-4",
    openalex = "W1964352595",
    pages = "225-232",
    volume = "4",
    references = "doi1010160012821x71901269, doi101017s0022143000013666, doi101017s0022143000021687, doi101017s0022143000021699, doi101017s0022143000021948, doi101017s0032247400063804, doi101086627339, doi102475ajs2589664, epstein1970antarctic, thompson1975climatological"
}

Abstract The flow of the Antarctic ice sheet near Byrd Station is modeled using surface net accumulation-rate data, surface strain-rate data, and core-hole tilting results. The model empirically allows for the progressive development of ice fabric and for values of the vertical strain-rate nearer to zero at depth, and adjusts the strain-rates according to the effect of the climatic warming at the beginning of the Holocene. The validity of the model is supported by the agreements between calculated bed form and that measured by radar sounding, and between calculated and measured present-day ice-sheet thinning-rates. The ice was about 200 m thicker before thinning. The depth-age relationship for the Byrd Station ice core shows that the climatic change represented by the oxygen isotopic ratio of the ice began some 5000 years sooner than in north Greenland (Hammer and others 1978), but ended at about the same time.

@article{doi101017s0022143000014611,
    author = "Whillans, I. M.",
    title = "Ice Flow along the Byrd Station Strain Network, Antarctica",
    year = "1979",
    journal = "Journal of Glaciology",
    abstract = "Abstract The flow of the Antarctic ice sheet near Byrd Station is modeled using surface net accumulation-rate data, surface strain-rate data, and core-hole tilting results. The model empirically allows for the progressive development of ice fabric and for values of the vertical strain-rate nearer to zero at depth, and adjusts the strain-rates according to the effect of the climatic warming at the beginning of the Holocene. The validity of the model is supported by the agreements between calculated bed form and that measured by radar sounding, and between calculated and measured present-day ice-sheet thinning-rates. The ice was about 200 m thicker before thinning. The depth-age relationship for the Byrd Station ice core shows that the climatic change represented by the oxygen isotopic ratio of the ice began some 5000 years sooner than in north Greenland (Hammer and others 1978), but ended at about the same time.",
    url = "https://doi.org/10.1017/s0022143000014611",
    doi = "10.1017/s0022143000014611",
    openalex = "W19515275",
    references = "gow1973climatological"
}

Abstract Extensive radio echo-sounding has mapped the part of West Antarctica between Byrd Station, the Whitmore Mountains, the Transantarctic Mountains, and the Ross Ice Shelf. The ice sheet in this area is dominated by five major sub-parallel ice streams (A–E), which are up to 100 km wide and extend inland from the grounding line of the Ross Ice Shelf for about 400 km. Their positions have been determined by crevassing seen on radio echo-sounding records, trimetrogon photographs, and Landsat imagery. The ice streams are characterized by their flat transverse cross-sections, while the intervening ice sheet exhibits domes and ridges. Ice flow lines are defined from the ice-surface contour pattern and the trend of the ice streams. It is apparent from this work that the flow line passing through Byrd Station joins ice stream D. The bedrock of the area is relatively smooth near the Ross Ice Shelf, becoming rougher near Byrd Station and especially so near the Whitmore Mountains. Bedrock troughs, which control the positions of the ice streams, are believed to have a tectonic origin. In this paper the role of the ice streams in the glaciological regime of West Antarctica is investigated from radio-echo data and estimates of balance velocity, basal shear stress, and basal temperatures.

@article{doi101017s0022143000014659,
    author = "Rose, K. E.",
    title = "Characteristics of Ice Flow in Marie Byrd Land, Antarctica",
    year = "1979",
    journal = "Journal of Glaciology",
    abstract = "Abstract Extensive radio echo-sounding has mapped the part of West Antarctica between Byrd Station, the Whitmore Mountains, the Transantarctic Mountains, and the Ross Ice Shelf. The ice sheet in this area is dominated by five major sub-parallel ice streams (A–E), which are up to 100 km wide and extend inland from the grounding line of the Ross Ice Shelf for about 400 km. Their positions have been determined by crevassing seen on radio echo-sounding records, trimetrogon photographs, and Landsat imagery. The ice streams are characterized by their flat transverse cross-sections, while the intervening ice sheet exhibits domes and ridges. Ice flow lines are defined from the ice-surface contour pattern and the trend of the ice streams. It is apparent from this work that the flow line passing through Byrd Station joins ice stream D. The bedrock of the area is relatively smooth near the Ross Ice Shelf, becoming rougher near Byrd Station and especially so near the Whitmore Mountains. Bedrock troughs, which control the positions of the ice streams, are believed to have a tectonic origin. In this paper the role of the ice streams in the glaciological regime of West Antarctica is investigated from radio-echo data and estimates of balance velocity, basal shear stress, and basal temperatures.",
    url = "https://doi.org/10.1017/s0022143000014659",
    doi = "10.1017/s0022143000014659",
    openalex = "W109693233"
}

Abstract The flow of the Antarctic ice sheet near Byrd Station is modeled using surface net accumulation-rate data, surface strain-rate data, and core-hole tilting results. The model empirically allows for the progressive development of ice fabric and for values of the vertical strain-rate nearer to zero at depth, and adjusts the strain-rates according to the effect of the climatic warming at the beginning of the Holocene. The validity of the model is supported by the agreements between calculated bed form and that measured by radar sounding, and between calculated and measured present-day ice-sheet thinning-rates. The ice was about 200 m thicker before thinning. The depth-age relationship for the Byrd Station ice core shows that the climatic change represented by the oxygen isotopic ratio of the ice began some 5000 years sooner than in north Greenland (Hammer and others 1978), but ended at about the same time.

@article{doi103189s0022143000014611,
    author = "Whillans, I. M.",
    title = "Ice Flow along the Byrd Station Strain Network, Antarctica",
    year = "1979",
    journal = "Journal of Glaciology",
    abstract = "Abstract The flow of the Antarctic ice sheet near Byrd Station is modeled using surface net accumulation-rate data, surface strain-rate data, and core-hole tilting results. The model empirically allows for the progressive development of ice fabric and for values of the vertical strain-rate nearer to zero at depth, and adjusts the strain-rates according to the effect of the climatic warming at the beginning of the Holocene. The validity of the model is supported by the agreements between calculated bed form and that measured by radar sounding, and between calculated and measured present-day ice-sheet thinning-rates. The ice was about 200 m thicker before thinning. The depth-age relationship for the Byrd Station ice core shows that the climatic change represented by the oxygen isotopic ratio of the ice began some 5000 years sooner than in north Greenland (Hammer and others 1978), but ended at about the same time.",
    url = "https://doi.org/10.3189/s0022143000014611",
    doi = "10.3189/s0022143000014611",
    openalex = "W4249938455",
    references = "gow1973climatological"
}

@misc{nakashima1981formulation1,
    author = "Nakashima, T. and Fox, S. W",
    title = "Formulation of peptides by single or multiple additions of ATP to suspensions of nucleoproteinoid microparticles",
    year = "1981",
    howpublished = "BioSystems, v. 14, p. 151-161",
    note = "talkorigins\_source = {true}; raw\_reference = {Nakashima, T., and Fox, S. W., 1981, Formulation of peptides by single or multiple additions of ATP to suspensions of nucleoproteinoid microparticles: BioSystems, v. 14, p. 151-161.}"
}

Analyses of ice cores taken from the Antarctic ice sheet can provide information on the environmental conditions under which the ice was formed. New results from measurements of gas content and stable isotope ratios in the Byrd station ice core are discussed and interpreted in terms of past iceflow changes. 165 selected ice samples from 32 different depth levels along the core were processed for total gas content V and stable isotope ratios. This large dataset is used to discuss the variability and significance of the values of V at different depths. The short term variations of V are mainly explained by heterogeneities of the pore volume when the firn pores close off. The general trends in the values of V with depth are then used to investigate the possibility of past changes in the ice sheet. They suggest near-steady flow during the past few tens of thousands of years and that a thickening of about 200 to 250 m occurred in this area of the ice sheet at the end of the last ice age. This thickening could be due to a change in the accumulation rate.

@article{doi101017s0260305500002901,
    author = "Raynaud, Dominique and Whillans, I. M.",
    title = "Air Content Of The Byrd Core And Past Changes In The West Antarctic Ice Sheet",
    year = "1982",
    journal = "Annals of Glaciology",
    abstract = "Analyses of ice cores taken from the Antarctic ice sheet can provide information on the environmental conditions under which the ice was formed. New results from measurements of gas content and stable isotope ratios in the Byrd station ice core are discussed and interpreted in terms of past iceflow changes. 165 selected ice samples from 32 different depth levels along the core were processed for total gas content V and stable isotope ratios. This large dataset is used to discuss the variability and significance of the values of V at different depths. The short term variations of V are mainly explained by heterogeneities of the pore volume when the firn pores close off. The general trends in the values of V with depth are then used to investigate the possibility of past changes in the ice sheet. They suggest near-steady flow during the past few tens of thousands of years and that a thickening of about 200 to 250 m occurred in this area of the ice sheet at the end of the last ice age. This thickening could be due to a change in the accumulation rate.",
    url = "https://doi.org/10.1017/s0260305500002901",
    doi = "10.1017/s0260305500002901",
    openalex = "W16765150"
}

Polar ice cores contain long and detailed records of paleoatmospheric composition, paleoclimate, and their evolution through time. By making a complete ionic balance in melted samples of ice, it is possible to evaluate the origin (identification of chemical compounds) and sources (continental, marine, volcanic, extraterrestrial) of soluble impurities contained in these ice cores. Once these are known, an attempt can be made to try and explain the cause of any observed changes. In this paper we present results of analyses of the major soluble impurities (H +, Na +, NH 4 +, K +, SO 4 −, NO 3 −, Cl −) made on bulk samples selected at approximately 50 m intervals down the length of an ice core from Byrd Station, Antarctica (80°01′S, 119°31′W, 1530 m). Most samples are in ionic balance, and it is therefore possible to suggest with which compounds the ionic impurities are linked. These compounds include an important contribution from both sea salts (NaCl and Na 2 SO 4) and strong acids (approximately equal amounts of HNO 3 and H 2 SO 4). The Cl/Na mole ratio is found to be quite stable throughout the core and hovers about the expected bulk sea water ratio. In general, the marine‐derived components at Byrd Station decreased by a factor of 2 between the Late Glacial Maximum and Holocene while the gas‐derived acid components decreased by a factor of only 1.5. Some possible causes of these variations are suggested.

@article{palais1985soluble,
    author = "Palais, Julie M. and Legrand, Michel",
    title = "Soluble impurities in the Byrd Station ice core, Antarctica: Their origin and sources",
    year = "1985",
    journal = "Journal of Geophysical Research: Oceans",
    abstract = "Polar ice cores contain long and detailed records of paleoatmospheric composition, paleoclimate, and their evolution through time. By making a complete ionic balance in melted samples of ice, it is possible to evaluate the origin (identification of chemical compounds) and sources (continental, marine, volcanic, extraterrestrial) of soluble impurities contained in these ice cores. Once these are known, an attempt can be made to try and explain the cause of any observed changes. In this paper we present results of analyses of the major soluble impurities (H +, Na +, NH 4 +, K +, SO 4 −, NO 3 −, Cl −) made on bulk samples selected at approximately 50 m intervals down the length of an ice core from Byrd Station, Antarctica (80°01′S, 119°31′W, 1530 m). Most samples are in ionic balance, and it is therefore possible to suggest with which compounds the ionic impurities are linked. These compounds include an important contribution from both sea salts (NaCl and Na 2 SO 4) and strong acids (approximately equal amounts of HNO 3 and H 2 SO 4). The Cl/Na mole ratio is found to be quite stable throughout the core and hovers about the expected bulk sea water ratio. In general, the marine‐derived components at Byrd Station decreased by a factor of 2 between the Late Glacial Maximum and Holocene while the gas‐derived acid components decreased by a factor of only 1.5. Some possible causes of these variations are suggested.",
    url = "https://doi.org/10.1029/jc090ic01p01143",
    doi = "10.1029/jc090ic01p01143",
    number = "C1",
    openalex = "W2091727916",
    pages = "1143-1154",
    volume = "90",
    references = "doi1010160012821x71901269, doi101017s0260305500002901, doi101029jc087ic04p03052, doi101029jc088ic10p06013, doi101038235429a0, doi101038280479a0, doi101038280644a0, doi101038293391a0, doi101098rstb19770103, doi103402tellusav11i49333"
}

Uniaxial and biaxial compression tests were carried out on ice samples from the 2040 m Vostok ice core. It is shown that the ice viscosity does not significantly change with depth. As a result the high impurity content in glacial ice does not seem to influence the mechanical behavior of the Vostok ice core. The measured enhancement factor, smaller than 1, is caused by the particular orientation of c -axes in this polar ice. It is deduced that the viscosity of Vostok ice for horizontal shear is high compared with that of other ice cores.

@article{doi101017s0260305500004316,
    author = "Pimienta, P. and Duval, P. and Lipenkov, V.",
    title = "Mechanical Behavior of Ice Along the 2040 m Vostok Core, Antarctica",
    year = "1988",
    journal = "Annals of Glaciology",
    abstract = "Uniaxial and biaxial compression tests were carried out on ice samples from the 2040 m Vostok ice core. It is shown that the ice viscosity does not significantly change with depth. As a result the high impurity content in glacial ice does not seem to influence the mechanical behavior of the Vostok ice core. The measured enhancement factor, smaller than 1, is caused by the particular orientation of c -axes in this polar ice. It is deduced that the viscosity of Vostok ice for horizontal shear is high compared with that of other ice cores.",
    url = "https://doi.org/10.1017/s0260305500004316",
    doi = "10.1017/s0260305500004316",
    openalex = "W1672523318",
    references = "palais1985soluble"
}

The first ice-core record of both the Holocene and Wisconsin/Würm Late Glacial Stage (LGS) from the subtropics has been extracted from three ice cores to bedrock from the Dunde ice cap on the north-central Qinghai-Tibetan Plateau. Ice thicknesses at the ice-cap summit average 138 m, the bedrock surface is relatively flat, surface and basal temperatures are −7.3 and −4.7°C, respectively and the ice cap exhibits radial flow away from the summit dome. These records reveal a major change in the climate of the plateau ∼10 000 years ago and suggest that LGS conditions were colder, wetter and dustier than Holocene conditions. This is inferred from the more negative δ 18 O ratios, increased dust content, decreased soluble aerosol concentrations, and reduced ice-crystal sizes, which characterize the LGS part of the cores. Total β radioactivity from shallow ice cores indicates that over the last 24 years the average accumulation rate has been ∼400 mm a −1 at the summit. The ice cores have been dated using a combination of annual layers in the insoluble dust and δ 18 O in the upper sections of core, visible dust layers which are annual, and ice-flow modeling. The oxygen-isotope record which serves as a temperature proxy indicates that the last 60 years have been the warmest in the entire record.

@article{doi101017s0260305500008776,
    author = "Thompson, Lonnie G. and Mosley‐Thompson, Ellen and Davis, M. E. and Bolzan, John F. and Dai, J. and Klein, L. and Gundestrup, N. and Yao, Tandong and Wu, X. and Xie, Zhouqing",
    title = "Glacial Stage Ice-Core Records from the Subtropical Dunde Ice Cap, China",
    year = "1990",
    journal = "Annals of Glaciology",
    abstract = "The first ice-core record of both the Holocene and Wisconsin/Würm Late Glacial Stage (LGS) from the subtropics has been extracted from three ice cores to bedrock from the Dunde ice cap on the north-central Qinghai-Tibetan Plateau. Ice thicknesses at the ice-cap summit average 138 m, the bedrock surface is relatively flat, surface and basal temperatures are −7.3 and −4.7°C, respectively and the ice cap exhibits radial flow away from the summit dome. These records reveal a major change in the climate of the plateau ∼10 000 years ago and suggest that LGS conditions were colder, wetter and dustier than Holocene conditions. This is inferred from the more negative δ 18 O ratios, increased dust content, decreased soluble aerosol concentrations, and reduced ice-crystal sizes, which characterize the LGS part of the cores. Total β radioactivity from shallow ice cores indicates that over the last 24 years the average accumulation rate has been ∼400 mm a −1 at the summit. The ice cores have been dated using a combination of annual layers in the insoluble dust and δ 18 O in the upper sections of core, visible dust layers which are annual, and ice-flow modeling. The oxygen-isotope record which serves as a temperature proxy indicates that the last 60 years have been the warmest in the entire record.",
    url = "https://doi.org/10.1017/s0260305500008776",
    doi = "10.1017/s0260305500008776",
    openalex = "W1641377888",
    references = "angelis1987aerosol, doi101007bf00435818, doi1010160031018286901197, doi101017s0022143000030288, doi101029jd093id08p09341, doi101038235429a0, doi101038266508a0, doi101038336568a0, doi101126science2394839504, doi101126science2464929474"
}

The first ice-core record of both the Holocene and Wisconsin/Würm Late Glacial Stage (LGS) from the subtropics has been extracted from three ice cores to bedrock from the Dunde ice cap on the north-central Qinghai-Tibetan Plateau. Ice thicknesses at the ice-cap summit average 138 m, the bedrock surface is relatively flat, surface and basal temperatures are −7.3 and −4.7°C, respectively and the ice cap exhibits radial flow away from the summit dome. These records reveal a major change in the climate of the plateau ∼10 000 years ago and suggest that LGS conditions were colder, wetter and dustier than Holocene conditions. This is inferred from the more negative δ 18 O ratios, increased dust content, decreased soluble aerosol concentrations, and reduced ice-crystal sizes, which characterize the LGS part of the cores. Total β radioactivity from shallow ice cores indicates that over the last 24 years the average accumulation rate has been ∼400 mm a −1 at the summit. The ice cores have been dated using a combination of annual layers in the insoluble dust and δ 18 O in the upper sections of core, visible dust layers which are annual, and ice-flow modeling. The oxygen-isotope record which serves as a temperature proxy indicates that the last 60 years have been the warmest in the entire record.

@article{doi103189s0260305500008776,
    author = "Thompson, Lonnie G. and Mosley‐Thompson, Ellen and Davis, M. E. and Bolzan, John F. and Dai, J. and Klein, L. and Gundestrup, N. and Yao, Tandong and Wu, X. and Xie, Zhouqing",
    title = "Glacial Stage Ice-Core Records from the Subtropical Dunde Ice Cap, China",
    year = "1990",
    journal = "Annals of Glaciology",
    abstract = "The first ice-core record of both the Holocene and Wisconsin/Würm Late Glacial Stage (LGS) from the subtropics has been extracted from three ice cores to bedrock from the Dunde ice cap on the north-central Qinghai-Tibetan Plateau. Ice thicknesses at the ice-cap summit average 138 m, the bedrock surface is relatively flat, surface and basal temperatures are −7.3 and −4.7°C, respectively and the ice cap exhibits radial flow away from the summit dome. These records reveal a major change in the climate of the plateau ∼10 000 years ago and suggest that LGS conditions were colder, wetter and dustier than Holocene conditions. This is inferred from the more negative δ 18 O ratios, increased dust content, decreased soluble aerosol concentrations, and reduced ice-crystal sizes, which characterize the LGS part of the cores. Total β radioactivity from shallow ice cores indicates that over the last 24 years the average accumulation rate has been ∼400 mm a −1 at the summit. The ice cores have been dated using a combination of annual layers in the insoluble dust and δ 18 O in the upper sections of core, visible dust layers which are annual, and ice-flow modeling. The oxygen-isotope record which serves as a temperature proxy indicates that the last 60 years have been the warmest in the entire record.",
    url = "https://doi.org/10.3189/s0260305500008776",
    doi = "10.3189/s0260305500008776",
    openalex = "W4246535932",
    references = "angelis1987aerosol, doi1010079783642733338, doi1010160031018286901197, doi101017s0022143000030288, doi101029jd093id08p09341, doi101038235429a0, doi101038266508a0, doi101038336568a0, doi101126science2394839504, doi101126science2464929474"
}

A continuous ECM profile (strong acid concentration) has been measured along the 2191 m of ice core recovered at Byrd Station, Antarctica, in 1968. The ECM profile reveals continuous and systematic seasonal changes which are used for dating the ice core back to 50 000 bp. Hammer and others: ECM stratigraphic dating of Byrd Station ice core, Antarctica

@article{hammer1994electrical,
    author = "Hammer, C.U. and clausen, H.B. and Langway, C.C.",
    title = "Electrical conductivity method (ECM) stratigraphic dating of the Byrd Station ice core, Antarctica",
    year = "1994",
    journal = "Annals of Glaciology",
    abstract = "A continuous ECM profile (strong acid concentration) has been measured along the 2191 m of ice core recovered at Byrd Station, Antarctica, in 1968. The ECM profile reveals continuous and systematic seasonal changes which are used for dating the ice core back to 50 000 bp. Hammer and others: ECM stratigraphic dating of Byrd Station ice core, Antarctica",
    url = "https://doi.org/10.1017/s0260305500016323",
    doi = "10.1017/s0260305500016323",
    openalex = "W1966342721",
    pages = "115-120",
    volume = "20",
    references = "doi101017s0022143000015227, doi101038235429a0, doi101038280644a0, doi101038288230a0, doi101038316591a0, doi101038359311a0, doi101038362527a0, doi101111j160008891989tb00321x, doi101126science21845791273, doi103402tellusbv41i415100"
}

The size distribution of insoluble microparticles (dust) in the particle size interval 0.4–6.0 μm radius has been measured in more than 1400 samples from the Greenland Ice Core Project (GRIP) deep ice core from Summit, Greenland. The samples were taken from ice core segments representing 32 climatic periods including ice from the Eem interglacial and ice from below the Eemian ice. The mean dust volume distributions from the climatic periods are compared, and the relationship of total dust mass to the concentration of Ca 2+ and to the stable isotopic composition (δ 18 O) is investigated. The dust volume distributions are found to be lognormal in the size interval 0.4–2.0 μm with nearly identical shapes. Changes of the lognormal part of the volume distributions are found to be connected to the total dust mass in a systematic way. The total dust mass is correlated to the Ca 2+ concentration, and data do not show any enrichment in Ca 2+ from exposed continental shelves due to lower sea levels during the last glacial maximum. The total dust mass is strongly connected to δ 18 O. The volume distribution of the particles in the size interval 2.0–6.0 μm is found to be almost the same in most periods. The exceptions are the “cold” periods in the last part of the last glacial period, where the volume of these particles is higher than in most periods, and the periods from the Eemian and just above the Eemian where the volume of these particles is lower. The volume distributions of both the Eemian “warm” periods and the “cold” Eemian events are different from the distributions in ice from both below and above the Eemian ice. Climate changes appear to have modified the processes of production, transport, modification, and deposition of the dust aerosol in the same way over the last 120,000 years or more.

@article{doi10102997jc01490,
    author = "Steffensen, J. P.",
    title = "The size distribution of microparticles from selected segments of the Greenland Ice Core Project ice core representing different climatic periods",
    year = "1997",
    journal = "Journal of Geophysical Research Atmospheres",
    abstract = "The size distribution of insoluble microparticles (dust) in the particle size interval 0.4–6.0 μm radius has been measured in more than 1400 samples from the Greenland Ice Core Project (GRIP) deep ice core from Summit, Greenland. The samples were taken from ice core segments representing 32 climatic periods including ice from the Eem interglacial and ice from below the Eemian ice. The mean dust volume distributions from the climatic periods are compared, and the relationship of total dust mass to the concentration of Ca 2+ and to the stable isotopic composition (δ 18 O) is investigated. The dust volume distributions are found to be lognormal in the size interval 0.4–2.0 μm with nearly identical shapes. Changes of the lognormal part of the volume distributions are found to be connected to the total dust mass in a systematic way. The total dust mass is correlated to the Ca 2+ concentration, and data do not show any enrichment in Ca 2+ from exposed continental shelves due to lower sea levels during the last glacial maximum. The total dust mass is strongly connected to δ 18 O. The volume distribution of the particles in the size interval 2.0–6.0 μm is found to be almost the same in most periods. The exceptions are the “cold” periods in the last part of the last glacial period, where the volume of these particles is higher than in most periods, and the periods from the Eemian and just above the Eemian where the volume of these particles is lower. The volume distributions of both the Eemian “warm” periods and the “cold” Eemian events are different from the distributions in ice from both below and above the Eemian ice. Climate changes appear to have modified the processes of production, transport, modification, and deposition of the dust aerosol in the same way over the last 120,000 years or more.",
    url = "https://doi.org/10.1029/97jc01490",
    doi = "10.1029/97jc01490",
    openalex = "W2118349946"
}

Aerosol and fresh snow concentrations have been determined at three coastal Antarctic stations, Dumont d'Urville, Halley, and Neumayer. Model estimates suggest that dry deposition, including that caused by wind pumping, is only a minor contributor (of order 1%) to chemical fluxes at these sites with relatively high snow accumulation. Larger dry deposition fluxes are possible for very large aerosol particles, including sea‐salt aerosol. Measurements of surface snow on successive days provide experimental data that constrain the contribution of dry deposition to probably less than 10% of annual fluxes for all ions, although very high episodic fluxes of giant sea‐salt aerosol cannot be ruled out. Spatial variability, and frequent snow, fog and drift events, make it difficult to improve this quantification. Both theory and measurement suggest that fog deposition is also a minor contributor to the annual flux (probably <1%). Sublimation of surface snow and of blowing snow may increase snow concentrations by a few percent, with a larger role in summer, but should not affect fluxes. Wet deposition in falling snow appears to be by far the major contributor. However, the relationship between concentrations in snow and in simultaneously sampled aerosol at ground level was poor for most species. Scavenging ratios derived from these data are higher than those from the limited data previously available, but have huge uncertainties associated with them. Particularly at sites with frequent drifting snow, groundlevel aerosol measurements may be inappropriate for deriving scavenging ratios. Despite this, there is a general seasonal coincidence of high aerosol concentrations and high snow concentrations. We are also able to trace the chemistry of fresh snowfall to an ice core collected up to 2 years later. Although some major snowfall events may be missing, it seems that, as expected, there is no significant postdepositional modification of chemistry for aerosol species in the top meter of firn.

@article{doi10102997jd02613,
    author = "Wolff, Eric and Hall, Julie and Mulvaney, Robert and Pasteur, Elizabeth C. and Wagenbach, Dietmar and Legrand, Michel",
    title = "Relationship between chemistry of air, fresh snow and firn cores for aerosol species in coastal Antarctica",
    year = "1998",
    journal = "Journal of Geophysical Research Atmospheres",
    abstract = "Aerosol and fresh snow concentrations have been determined at three coastal Antarctic stations, Dumont d'Urville, Halley, and Neumayer. Model estimates suggest that dry deposition, including that caused by wind pumping, is only a minor contributor (of order 1\%) to chemical fluxes at these sites with relatively high snow accumulation. Larger dry deposition fluxes are possible for very large aerosol particles, including sea‐salt aerosol. Measurements of surface snow on successive days provide experimental data that constrain the contribution of dry deposition to probably less than 10\% of annual fluxes for all ions, although very high episodic fluxes of giant sea‐salt aerosol cannot be ruled out. Spatial variability, and frequent snow, fog and drift events, make it difficult to improve this quantification. Both theory and measurement suggest that fog deposition is also a minor contributor to the annual flux (probably <1\%). Sublimation of surface snow and of blowing snow may increase snow concentrations by a few percent, with a larger role in summer, but should not affect fluxes. Wet deposition in falling snow appears to be by far the major contributor. However, the relationship between concentrations in snow and in simultaneously sampled aerosol at ground level was poor for most species. Scavenging ratios derived from these data are higher than those from the limited data previously available, but have huge uncertainties associated with them. Particularly at sites with frequent drifting snow, groundlevel aerosol measurements may be inappropriate for deriving scavenging ratios. Despite this, there is a general seasonal coincidence of high aerosol concentrations and high snow concentrations. We are also able to trace the chemistry of fresh snowfall to an ice core collected up to 2 years later. Although some major snowfall events may be missing, it seems that, as expected, there is no significant postdepositional modification of chemistry for aerosol species in the top meter of firn.",
    url = "https://doi.org/10.1029/97jd02613",
    doi = "10.1029/97jd02613",
    openalex = "W2045948940"
}

A comparison is made of the Holocene records obtained from water isotope measurements along 11 ice cores from coastal and central sites in east Antarctica (Vostok, Dome B, Plateau Remote, Komsomolskaia, Dome C, Taylor Dome, Dominion Range, D47, KM105, and Law Dome) and west Antarctica (Byrd), with temporal resolution from 20 to 50 yr. The long-term trends possibly reflect local ice sheet elevation fluctuations superimposed on common climatic fluctuations. All the records confirm the widespread Antarctic early Holocene optimum between 11,500 and 9000 yr; in the Ross Sea sector, a secondary optimum is identified between 7000 and 5000 yr, whereas all eastern Antarctic sites show a late optimum between 6000 and 3000 yr. Superimposed on the long time trend, all the records exhibit 9 aperiodic millennial-scale oscillations. Climatic optima show a reduced pacing between warm events (typically 800 yr), whereas cooler periods are associated with less-frequent warm events (pacing >1200 yr).

@article{doi101006qres20002172,
    author = "Masson‐Delmotte, Valérie and Vimeux, Françoise and Jouzel, Jean and Morgan, Vin and Delmotte, Marc and Ciais, Philippe and Hammer, C. U. and Johnsen, S. J. and Lipenkov, V. and Mosley‐Thompson, Ellen and Petit, Jean‐Robert and Steig, Eric J. and Stiévenard, M. and Vaikmäe, Rein",
    title = "Holocene Climate Variability in Antarctica Based on 11 Ice-Core Isotopic Records",
    year = "2000",
    journal = "Quaternary Research",
    abstract = "A comparison is made of the Holocene records obtained from water isotope measurements along 11 ice cores from coastal and central sites in east Antarctica (Vostok, Dome B, Plateau Remote, Komsomolskaia, Dome C, Taylor Dome, Dominion Range, D47, KM105, and Law Dome) and west Antarctica (Byrd), with temporal resolution from 20 to 50 yr. The long-term trends possibly reflect local ice sheet elevation fluctuations superimposed on common climatic fluctuations. All the records confirm the widespread Antarctic early Holocene optimum between 11,500 and 9000 yr; in the Ross Sea sector, a secondary optimum is identified between 7000 and 5000 yr, whereas all eastern Antarctic sites show a late optimum between 6000 and 3000 yr. Superimposed on the long time trend, all the records exhibit 9 aperiodic millennial-scale oscillations. Climatic optima show a reduced pacing between warm events (typically 800 yr), whereas cooler periods are associated with less-frequent warm events (pacing >1200 yr).",
    url = "https://doi.org/10.1006/qres.2000.2172",
    doi = "10.1006/qres.2000.2172",
    openalex = "W2082051726",
    references = "hammer1994electrical"
}

Annually‐dated snowpit and ice core records from two areas of West Antarctica are used to investigate spatial accumulation patterns and to evaluate temporal accumulation rate/glaciochemical concentration and flux relationships. Mean accumulation rate gradients in Marie Byrd Land (11–23 gcm −2 yr −1 over 150 km, decreasing to the south) and Siple Dome (10–18 gcm −2 yr −1 over 60 km, decreasing to the south) are consistent for at least the last several decades, and demonstrate the influence of the offshore quasi‐permanent Amundsen Sea low pressure system on moisture flux into the region. Local and regional‐scale topography in both regions appears to affect orographic lifting, air mass trajectories, and accumulation distribution. Linear regression of mean annual soluble ion concentration and flux data vs. accumulation rates in both regions indicates that 1) concentrations are independent of and thus not a rescaling of accumulation rate time‐series, and 2) chemical flux to the ice sheet surface is mainly via wet deposition, and changes in atmospheric concentration play a significant role. We therefore suggest that, in the absence of detailed air/snow transfer models, ice core chemical concentration and not flux time‐series provide a better estimate of past aerosol loading in West Antarctica.

@article{doi1010292000gl011499,
    author = "Kreutz, K. J. and Mayewski, Paul A. and Meeker, L. David and Twickler, Mark S. and Whitlow, Sallie I.",
    title = "The effect of spatial and temporal accumulation rate variability in west Antarctica on soluble ion deposition",
    year = "2000",
    journal = "Geophysical Research Letters",
    abstract = "Annually‐dated snowpit and ice core records from two areas of West Antarctica are used to investigate spatial accumulation patterns and to evaluate temporal accumulation rate/glaciochemical concentration and flux relationships. Mean accumulation rate gradients in Marie Byrd Land (11–23 gcm −2 yr −1 over 150 km, decreasing to the south) and Siple Dome (10–18 gcm −2 yr −1 over 60 km, decreasing to the south) are consistent for at least the last several decades, and demonstrate the influence of the offshore quasi‐permanent Amundsen Sea low pressure system on moisture flux into the region. Local and regional‐scale topography in both regions appears to affect orographic lifting, air mass trajectories, and accumulation distribution. Linear regression of mean annual soluble ion concentration and flux data vs. accumulation rates in both regions indicates that 1) concentrations are independent of and thus not a rescaling of accumulation rate time‐series, and 2) chemical flux to the ice sheet surface is mainly via wet deposition, and changes in atmospheric concentration play a significant role. We therefore suggest that, in the absence of detailed air/snow transfer models, ice core chemical concentration and not flux time‐series provide a better estimate of past aerosol loading in West Antarctica.",
    url = "https://doi.org/10.1029/2000gl011499",
    doi = "10.1029/2000gl011499",
    openalex = "W1982312776",
    references = "doi101017s002214300001385x, doi101017s0022143000034845, doi101017s0954102099000140, doi1010291999jd901069, doi10102996jd01769, doi10102997jd02613, doi101029rg017i008p01983, doi101051jphyscol1987111, doi1011751520044219990120933ronsmb20co2, doi1011751520044220000131406eaardo20co2, doi103189172756500781833449"
}

Extensive archives of volcanic history are available from ice cores recovered from the Antarctic and Greenland ice sheets that receive and preserve sulfuric acid fallout from explosive volcanic eruptions. The continuous, detailed (average 1.2 samples per year) sulfate measurements of a 200‐m ice core from a remote East Antarctica site (Plateau Remote) provide a record of Southern Hemisphere volcanism over the last 4100 years. This extends the volcanic record beyond the last 1000 years covered by previous Antarctic ice cores. An average of 1.3 eruptions per century is recorded in East Antarctic snow during the last 4100 years. The record shows that on average eruptions have been more frequent and more explosive during the most recent 2000 years than in the previous 2100 years. Intervals up to 500 years are observed in which few explosive volcanic signals are detected. These periods include 2000–1500 B.C. (no eruptions), 500–1 B.C. (two eruptions), and 700–1200 A.D. (two eruptions). This new Plateau Remote volcanic record is compared with those from previous Antarctic ice cores covering the last 1000 years. In terms of dates for volcanic events, the new record is in excellent agreement with the earlier records. However, significant discrepancies are found between these records in relative signal magnitude (volcanic flux) of several well‐known events. The discrepancies among the records may be explained by the differences in the glaciology at the ice core sites, analytical techniques used for sulfate and sulfuric acid measurement, and the selection of detection thresholds for volcanic signals. Comparison with Greenland ice core volcanic records indicates that during the last millennium, nine large, low‐latitude eruptions contributed significant amounts of volcanic aerosols to the atmosphere of both hemispheres, potentially affecting global climate. In contrast, only one or possibly two such eruptions are found in the first millennium A.D.

@article{doi1010292000jd900254,
    author = "Cole‐Dai, Jihong and Mosley‐Thompson, Ellen and Wight, Shawn P. and Thompson, Lonnie G.",
    title = "A 4100‐year record of explosive volcanism from an East Antarctica ice core",
    year = "2000",
    journal = "Journal of Geophysical Research Atmospheres",
    abstract = "Extensive archives of volcanic history are available from ice cores recovered from the Antarctic and Greenland ice sheets that receive and preserve sulfuric acid fallout from explosive volcanic eruptions. The continuous, detailed (average 1.2 samples per year) sulfate measurements of a 200‐m ice core from a remote East Antarctica site (Plateau Remote) provide a record of Southern Hemisphere volcanism over the last 4100 years. This extends the volcanic record beyond the last 1000 years covered by previous Antarctic ice cores. An average of 1.3 eruptions per century is recorded in East Antarctic snow during the last 4100 years. The record shows that on average eruptions have been more frequent and more explosive during the most recent 2000 years than in the previous 2100 years. Intervals up to 500 years are observed in which few explosive volcanic signals are detected. These periods include 2000–1500 B.C. (no eruptions), 500–1 B.C. (two eruptions), and 700–1200 A.D. (two eruptions). This new Plateau Remote volcanic record is compared with those from previous Antarctic ice cores covering the last 1000 years. In terms of dates for volcanic events, the new record is in excellent agreement with the earlier records. However, significant discrepancies are found between these records in relative signal magnitude (volcanic flux) of several well‐known events. The discrepancies among the records may be explained by the differences in the glaciology at the ice core sites, analytical techniques used for sulfate and sulfuric acid measurement, and the selection of detection thresholds for volcanic signals. Comparison with Greenland ice core volcanic records indicates that during the last millennium, nine large, low‐latitude eruptions contributed significant amounts of volcanic aerosols to the atmosphere of both hemispheres, potentially affecting global climate. In contrast, only one or possibly two such eruptions are found in the first millennium A.D.",
    url = "https://doi.org/10.1029/2000jd900254",
    doi = "10.1029/2000jd900254",
    openalex = "W2073693306",
    references = "doi101029jd090id07p12901"
}

Geochemical data and geophysical measurements from a 554‐m ice‐core from Taylor Dome, East Antarctica, provide the basis for climate reconstruction in the western Ross Embayment through the entire Wisconsinan and Holocene. In comparison with ice cores from central East and West Antarctica, Taylor Dome shows greater variance of temperature, snow accumulation, and aerosol concentrations, reflecting significant variability in atmospheric circulation and air mass moisture content. Extreme aridity during the last glacial maximum at Taylor Dome reflects both colder temperatures and a shift in atmospheric circulation patterns associated with the advance of the Ross Sea ice sheet and accounts for regional alpine glacier retreats and high lake levels in the Dry Valleys. Inferred relationships between spatial accumulation gradients and ice sheet configuration indicate that advance of the Ross Sea ice sheet began in late marine isotope stage 5 or early stage 4. Precise dating of the Taylor Dome core achieved by trace‐gas correlation with central Greenland ice cores shows that abrupt deglacial warming at Taylor Dome was near‐synchronous with the ∼14.6 ka warming in central Greenland and lags the general warming trend in other Antarctic ice cores by at least 3000 years. Deglacial warming was following by a warm interval and transient cooling between 14.6 and 11.7 ka, synchronous with the Bølling/Allerød warming and Younger Dryas cooling events in central Greenland, and out of phase with the Antarctic Cold Reversal recorded in the Byrd (West Antarctica) ice core. Rapid climate changes during marine isotope stages 4 and 3 at Taylor Dome are similar in character to, and may be in phase with, the Northern Hemisphere stadial–interstadial (Dansgaard–Oeschger) events. Results from Taylor Dome illustrate the importance of obtaining ice cores from multiple Antarctic sites, to provide wide spatial coverage of past climate and ice dynamics.

@article{doi101111j04353676200000122x,
    author = "Steig, Eric J. and Morse, D. L. and Waddington, Edwin D. and Stuiver, Minze and Grootes, Pieter Meiert and Mayewski, Paul A. and Twickler, Mark S. and Whitlow, Sallie I.",
    title = "Wisconsinan and holocene climate history from an ice core at taylor dome, western ross embayment, antarctica",
    year = "2000",
    journal = "Geografiska Annaler Series A Physical Geography",
    abstract = "Geochemical data and geophysical measurements from a 554‐m ice‐core from Taylor Dome, East Antarctica, provide the basis for climate reconstruction in the western Ross Embayment through the entire Wisconsinan and Holocene. In comparison with ice cores from central East and West Antarctica, Taylor Dome shows greater variance of temperature, snow accumulation, and aerosol concentrations, reflecting significant variability in atmospheric circulation and air mass moisture content. Extreme aridity during the last glacial maximum at Taylor Dome reflects both colder temperatures and a shift in atmospheric circulation patterns associated with the advance of the Ross Sea ice sheet and accounts for regional alpine glacier retreats and high lake levels in the Dry Valleys. Inferred relationships between spatial accumulation gradients and ice sheet configuration indicate that advance of the Ross Sea ice sheet began in late marine isotope stage 5 or early stage 4. Precise dating of the Taylor Dome core achieved by trace‐gas correlation with central Greenland ice cores shows that abrupt deglacial warming at Taylor Dome was near‐synchronous with the ∼14.6 ka warming in central Greenland and lags the general warming trend in other Antarctic ice cores by at least 3000 years. Deglacial warming was following by a warm interval and transient cooling between 14.6 and 11.7 ka, synchronous with the Bølling/Allerød warming and Younger Dryas cooling events in central Greenland, and out of phase with the Antarctic Cold Reversal recorded in the Byrd (West Antarctica) ice core. Rapid climate changes during marine isotope stages 4 and 3 at Taylor Dome are similar in character to, and may be in phase with, the Northern Hemisphere stadial–interstadial (Dansgaard–Oeschger) events. Results from Taylor Dome illustrate the importance of obtaining ice cores from multiple Antarctic sites, to provide wide spatial coverage of past climate and ice dynamics.",
    url = "https://doi.org/10.1111/j.0435-3676.2000.00122.x",
    doi = "10.1111/j.0435-3676.2000.00122.x",
    openalex = "W2094502958",
    references = "doi101017s0022143000030288, doi101029rg026i001p00149, hammer1994electrical"
}

Abstract The European Programme for Ice Coring in Antarctica includes a comprehensive pre-site survey on the inland ice plateau of Dronning Maud Land, Antarctica. The German glaciological programme during the 1997/98 field season was carried out along a 1200 km traverse on Amundsenisen and involved sampling the snow cover in pits and by shallow firn cores. This paper focuses on the accumulation studies. The cores were dated by dielectric-profiling and continuous-flow analysis. Distinct volcanogenic peaks and seasonal signals in the profiles served to establish a depth time-scale. The eruptions of Krakatoa, Tambora, an unknown volcano, Kuwae and El Chichon are well-documented in the ice. Variations of the accumulation rates over different times were inferred from the depth time-scales. A composite record of accumulation rates for the last 200 years was produced by stacking 12 annually resolved records. According to this, accumulation rates decreased in the 19th century and increased in the 20th century. The recent values are by no means extraordinary, as they do not exceed the values at the beginning of the 19th century. Variations in accumulation rates are most probably linked to temperature variations indicated in δ 18 O records from Amundsenisen.

@article{doi103189172756400781820705,
    author = "Oerter, H. and Wilhelms, Frank and Jung‐Rothenhäusler, Frederik and Göktas, Fidan and Miller, Heinrich and Graf, Walter H. and Sommer, Stefan",
    title = "Accumulation rates in Dronning Maud Land, Antarctica, as revealed by dielectric-profiling measurements of shallow firn cores",
    year = "2000",
    journal = "Annals of Glaciology",
    abstract = "Abstract The European Programme for Ice Coring in Antarctica includes a comprehensive pre-site survey on the inland ice plateau of Dronning Maud Land, Antarctica. The German glaciological programme during the 1997/98 field season was carried out along a 1200 km traverse on Amundsenisen and involved sampling the snow cover in pits and by shallow firn cores. This paper focuses on the accumulation studies. The cores were dated by dielectric-profiling and continuous-flow analysis. Distinct volcanogenic peaks and seasonal signals in the profiles served to establish a depth time-scale. The eruptions of Krakatoa, Tambora, an unknown volcano, Kuwae and El Chichon are well-documented in the ice. Variations of the accumulation rates over different times were inferred from the depth time-scales. A composite record of accumulation rates for the last 200 years was produced by stacking 12 annually resolved records. According to this, accumulation rates decreased in the 19th century and increased in the 20th century. The recent values are by no means extraordinary, as they do not exceed the values at the beginning of the 19th century. Variations in accumulation rates are most probably linked to temperature variations indicated in δ 18 O records from Amundsenisen.",
    url = "https://doi.org/10.3189/172756400781820705",
    doi = "10.3189/172756400781820705",
    openalex = "W1972100610"
}

Abstract Continuous, detailed isotope (δD and δ 18 O) profiles were obtained from eight snow pits dug in the vicinity of Vostok station, Antarctica, during the period 1984– 2000. In addition, snow samples taken along the 1km long accumulation-stake profile were measured to determine spatial variability in isotope composition of recent snow. the stacked δD time series spanning the last 55 years shows only weak correlation with the mean annual air temperature recorded at Vostok station. Significant oscillations of both snow accumulation and snow isotope composition with the periods 2.5, 5, 20 and, possibly, ~10 2 years observed at single points are interpreted in terms of drift of snow-accumulation waves of various scales on the surface of the ice sheet.

@article{doi103189172756402781816726,
    author = "Ekaykin, Alexey and Lipenkov, V. and Barkov, Narcisse I. and Petit, J. R. and Masson‐Delmotte, Valérie",
    title = "Spatial and temporal variability in isotope composition of recent snow in the vicinity of Vostok station, Antarctica: implications for ice-core record interpretation",
    year = "2002",
    journal = "Annals of Glaciology",
    abstract = "Abstract Continuous, detailed isotope (δD and δ 18 O) profiles were obtained from eight snow pits dug in the vicinity of Vostok station, Antarctica, during the period 1984– 2000. In addition, snow samples taken along the 1km long accumulation-stake profile were measured to determine spatial variability in isotope composition of recent snow. the stacked δD time series spanning the last 55 years shows only weak correlation with the mean annual air temperature recorded at Vostok station. Significant oscillations of both snow accumulation and snow isotope composition with the periods 2.5, 5, 20 and, possibly, \textasciitilde 10 2 years observed at single points are interpreted in terms of drift of snow-accumulation waves of various scales on the surface of the ice sheet.",
    url = "https://doi.org/10.3189/172756402781816726",
    doi = "10.3189/172756402781816726",
    openalex = "W2054799696",
    references = "doi101017s0022143000013423"
}

Volcanic ash, or tephra layers, are found in the Taylor Dome, Siple Dome A, and Siple Dome B ice cores. Significant shard concentrations are found at a number of depths in all three cores. Electron and ion microprobe analyses indicate that the geochemical composition of most layers is basaltic, basanitic, or trachytic, and the geochemical signatures of the layers suggest derivation from the Pleiades volcanic center, Mt. Melbourne volcano, or small mafic centers, probably in the Royal Society Range area. Presence of tephra layers suggests an episode of previously unrecognized Antarctic volcanic activity between 1776 and 1805 A.D., from at least two volcanic centers. A strong geochemical correlation (D = 3.49 and 3.97 with a value of 4 considered identical) is observed between tephra layers at depth of 79.2 m in the Taylor Dome ice core, and layers between 97.2 and 97.7 m depth in the Siple B core. This correlation, and the highly accurate depth‐age scale of the Siple B core suggest that the age of this horizon in the Taylor Dome ice core presented by Steig et al. [1998a, 2000] should be revised downward, to the younger age of 675 ± 25 years before 1995. This revised chronology is consistent with vertical strain measurements presented by Hawley et al. [2003].

@article{doi1010292002jb002056,
    author = "Dunbar, Nelia and Zielinski, Gregory A. and Voisins, Daniel T.",
    title = "Tephra layers in the Siple Dome and Taylor Dome ice cores, Antarctica: Sources and correlations",
    year = "2003",
    journal = "Journal of Geophysical Research Atmospheres",
    abstract = "Volcanic ash, or tephra layers, are found in the Taylor Dome, Siple Dome A, and Siple Dome B ice cores. Significant shard concentrations are found at a number of depths in all three cores. Electron and ion microprobe analyses indicate that the geochemical composition of most layers is basaltic, basanitic, or trachytic, and the geochemical signatures of the layers suggest derivation from the Pleiades volcanic center, Mt. Melbourne volcano, or small mafic centers, probably in the Royal Society Range area. Presence of tephra layers suggests an episode of previously unrecognized Antarctic volcanic activity between 1776 and 1805 A.D., from at least two volcanic centers. A strong geochemical correlation (D = 3.49 and 3.97 with a value of 4 considered identical) is observed between tephra layers at depth of 79.2 m in the Taylor Dome ice core, and layers between 97.2 and 97.7 m depth in the Siple B core. This correlation, and the highly accurate depth‐age scale of the Siple B core suggest that the age of this horizon in the Taylor Dome ice core presented by Steig et al. [1998a, 2000] should be revised downward, to the younger age of 675 ± 25 years before 1995. This revised chronology is consistent with vertical strain measurements presented by Hawley et al. [2003].",
    url = "https://doi.org/10.1029/2002jb002056",
    doi = "10.1029/2002jb002056",
    openalex = "W2036264079",
    references = "kyle1978compositions, kyle1981tephra"
}

Interpretation of the chemical layers measured in ice cores requires knowledge of processes occurring after their deposition on the ice sheet. We present evidence for the diffusion of soluble ions in the top 350 m of the Dome C ice core, Antarctica, that helps in explaining the unexpectedly broad volcanic peaks observed at depth. A windowed‐differencing operation applied to chemical time series indicates a damping of the signals over the past 11,000 years, independent of minor climatic variation, for sulfate and chloride, but not sodium. This implies a diffusive process is transporting both sulfate and chloride ions while the sodium ions remain fixed. We estimate the effective diffusivity in the core to be 4.7 × 10 −8 m 2 yr −1 for sulfate and 2.0 × 10 −7 m 2 yr −1 for chloride. These values are not high enough to significantly disrupt chemical interpretation in this section of core, but could be significant for older ice. The temperature of this section of ice (−53°C) implies that the predominantly acidic sulfate (and possibly chloride ions) will exist in the liquid phase while the sodium may be solid. We propose and develop two new mechanisms that could explain the observed solute movement. One involves the diffusion of solute through a connected vein network driven by liquid concentration imbalances instigated by the process of grain growth. The other considers a system of discontinuous veins where grain growth increases connectivity between isolated vein clusters allowing the spread of solute. In both mechanisms, the effective diffusivity is governed indirectly by grain growth rate; this may be a significant factor controlling effective diffusion in other cores.

@article{doi1010292002jd002538,
    author = "Barnes, Piers R. F. and Wolff, Eric and Mader, H. M. and Udisti, R. and Castellano, E. and Röthlisberger, Regine",
    title = "Evolution of chemical peak shapes in the Dome C, Antarctica, ice core",
    year = "2003",
    journal = "Journal of Geophysical Research Atmospheres",
    abstract = "Interpretation of the chemical layers measured in ice cores requires knowledge of processes occurring after their deposition on the ice sheet. We present evidence for the diffusion of soluble ions in the top 350 m of the Dome C ice core, Antarctica, that helps in explaining the unexpectedly broad volcanic peaks observed at depth. A windowed‐differencing operation applied to chemical time series indicates a damping of the signals over the past 11,000 years, independent of minor climatic variation, for sulfate and chloride, but not sodium. This implies a diffusive process is transporting both sulfate and chloride ions while the sodium ions remain fixed. We estimate the effective diffusivity in the core to be 4.7 × 10 −8 m 2 yr −1 for sulfate and 2.0 × 10 −7 m 2 yr −1 for chloride. These values are not high enough to significantly disrupt chemical interpretation in this section of core, but could be significant for older ice. The temperature of this section of ice (−53°C) implies that the predominantly acidic sulfate (and possibly chloride ions) will exist in the liquid phase while the sodium may be solid. We propose and develop two new mechanisms that could explain the observed solute movement. One involves the diffusion of solute through a connected vein network driven by liquid concentration imbalances instigated by the process of grain growth. The other considers a system of discontinuous veins where grain growth increases connectivity between isolated vein clusters allowing the spread of solute. In both mechanisms, the effective diffusivity is governed indirectly by grain growth rate; this may be a significant factor controlling effective diffusion in other cores.",
    url = "https://doi.org/10.1029/2002jd002538",
    doi = "10.1029/2002jd002538",
    openalex = "W2095002819",
    references = "doi1010160012821x80901703"
}

Abstract Sixteen high-resolution ice-core records from West Antarctica and South Pole are used to examine the spatial and temporal distribution of sulfate for the last 200 years. The preservation of seasonal layers throughout the length of each record results in a dating accuracy of better than 1 year based on known global-scale volcanic events. A dual transport source for West Antarctic sea-salt (ss) SO 4 2– and excess (xs) SO 4 2– is observed: lower-tropospheric for areas below 1000m elevation and mid-/upper-tropospheric/stratospheric for areas located above 1000 m. Our xsSO 4 2– records with volcanic peaks removed do not display any evidence of an anthropogenic impact on West Antarctic SO 4 2– concentrations but do reveal that a major climate transition takes place over West Antarctica at ∼1940. Global-scale volcanic eruptions appear as significant peaks in the robust-spline residual xsSO 4 2– records from sites located above 1000m elevation but do not appear in the residual records from sites located below 1000 m.

@article{doi103189172756404781814113,
    author = "Dixon, Daniel and Mayewski, Paul A. and Kaspari, S. and Sneed, Sharon B. and Handley, M.",
    title = "A 200 year sub-annual record of sulfate in West Antarctica, from 16 ice cores",
    year = "2004",
    journal = "Annals of Glaciology",
    abstract = "Abstract Sixteen high-resolution ice-core records from West Antarctica and South Pole are used to examine the spatial and temporal distribution of sulfate for the last 200 years. The preservation of seasonal layers throughout the length of each record results in a dating accuracy of better than 1 year based on known global-scale volcanic events. A dual transport source for West Antarctic sea-salt (ss) SO 4 2– and excess (xs) SO 4 2– is observed: lower-tropospheric for areas below 1000m elevation and mid-/upper-tropospheric/stratospheric for areas located above 1000 m. Our xsSO 4 2– records with volcanic peaks removed do not display any evidence of an anthropogenic impact on West Antarctic SO 4 2– concentrations but do reveal that a major climate transition takes place over West Antarctica at ∼1940. Global-scale volcanic eruptions appear as significant peaks in the robust-spline residual xsSO 4 2– records from sites located above 1000m elevation but do not appear in the residual records from sites located below 1000 m.",
    url = "https://doi.org/10.3189/172756404781814113",
    doi = "10.3189/172756404781814113",
    openalex = "W2066325978",
    references = "doi1010292000gl011499"
}

Abstract Thirteen annually resolved accumulation-rate records covering the last ~200 years from the Pine Island–Thwaites and Ross drainage systems and the South Pole are used to examine climate variability over West Antarctica. Accumulation is controlled spatially by the topography of the ice sheet, and temporally by changes in moisture transport and cyclonic activity. A comparison of mean accumulation since 1970 at each site to the long-term mean indicates an increase in accumulation for sites located in the western sector of the Pine Island–Thwaites drainage system. Accumulation is negatively associated with the Southern Oscillation Index (SOI) for sites near the ice divide, and periods of sustained negative SOI (1940–42, 1991–95) correspond to above-mean accumulation at most sites. Correlations of the accumulation-rate records with sea-level pressure (SLP) and the SOI suggest that accumulation near the ice divide and in the Ross drainage system may be associated with the mid-latitudes. The post-1970 increase in accumulation coupled with strong SLP–accumulation-rate correlations near the coast suggests recent intensification of cyclonic activity in the Pine Island– Thwaites drainage system.

@article{doi103189172756404781814447,
    author = "Kaspari, S. and Mayewski, Paul A. and Dixon, Daniel A. and Spikes, V. B. and Sneed, Sharon B. and Handley, Michael and Hamilton, G. S.",
    title = "Climate variability in West Antarctica derived from annual accumulation-rate records from ITASE firn/ice cores",
    year = "2004",
    journal = "Annals of Glaciology",
    abstract = "Abstract Thirteen annually resolved accumulation-rate records covering the last \textasciitilde 200 years from the Pine Island–Thwaites and Ross drainage systems and the South Pole are used to examine climate variability over West Antarctica. Accumulation is controlled spatially by the topography of the ice sheet, and temporally by changes in moisture transport and cyclonic activity. A comparison of mean accumulation since 1970 at each site to the long-term mean indicates an increase in accumulation for sites located in the western sector of the Pine Island–Thwaites drainage system. Accumulation is negatively associated with the Southern Oscillation Index (SOI) for sites near the ice divide, and periods of sustained negative SOI (1940–42, 1991–95) correspond to above-mean accumulation at most sites. Correlations of the accumulation-rate records with sea-level pressure (SLP) and the SOI suggest that accumulation near the ice divide and in the Ross drainage system may be associated with the mid-latitudes. The post-1970 increase in accumulation coupled with strong SLP–accumulation-rate correlations near the coast suggests recent intensification of cyclonic activity in the Pine Island– Thwaites drainage system.",
    url = "https://doi.org/10.3189/172756404781814447",
    doi = "10.3189/172756404781814447",
    openalex = "W1976316576",
    references = "doi101017s0022143000013423, doi1010292000gl011499, doi101029jc087ic06p04301"
}

A detailed history of Holocene volcanism was reconstructed using the sulfate record of the European Project for Ice Coring in Antarctica Dome C (EDC96) ice core. This first complete Holocene volcanic record from an Antarctic core provides a reliable database to compare with long records from Antarctic and Greenland ice cores. A threshold method based on statistical treatment of the lognormal sulfate flux distribution was used to differentiate volcanic sulfate spikes from sulfate background concentrations. Ninety‐six eruptions were identified in the EDC96 ice core during the Holocene, with a mean of 7.9 events per millennium. The frequency distribution (events per millennium) showed that the last 2000 years were a period of enhanced volcanic activity. EDC96 volcanic signatures for the last millennium are in good agreement with those recorded in other Antarctic ice cores. For older periods, comparison is in some cases less reliable, mainly because of dating uncertainties. Sulfate depositional fluxes of individual volcanic events vary greatly among the different cores. A volcanic flux normalization (volcanic flux/Tambora flux ratio) was used to evaluate the relative intensity of the same event recorded at different sites in the last millennium. Normalized flux variability for the same event showed the highest value in the 1100–1500 AD period. This pattern could mirror changes in regional transport linked to climatic variations such as slight warming stages in the Southern Hemisphere (Southern Hemisphere Medieval Warming–like period?).

@article{doi1010292004jd005259,
    author = "Castellano, E. and Becagli, Silvia and Hansson, Margareta and Hutterli, M. A. and Petit, J. R. and Rampino, Michael R. and Severi, Mirko and Steffensen, J. P. and Traversi, Rita and Udisti, R.",
    title = "Holocene volcanic history as recorded in the sulfate stratigraphy of the European Project for Ice Coring in Antarctica Dome C (EDC96) ice core",
    year = "2005",
    journal = "Journal of Geophysical Research Atmospheres",
    abstract = "A detailed history of Holocene volcanism was reconstructed using the sulfate record of the European Project for Ice Coring in Antarctica Dome C (EDC96) ice core. This first complete Holocene volcanic record from an Antarctic core provides a reliable database to compare with long records from Antarctic and Greenland ice cores. A threshold method based on statistical treatment of the lognormal sulfate flux distribution was used to differentiate volcanic sulfate spikes from sulfate background concentrations. Ninety‐six eruptions were identified in the EDC96 ice core during the Holocene, with a mean of 7.9 events per millennium. The frequency distribution (events per millennium) showed that the last 2000 years were a period of enhanced volcanic activity. EDC96 volcanic signatures for the last millennium are in good agreement with those recorded in other Antarctic ice cores. For older periods, comparison is in some cases less reliable, mainly because of dating uncertainties. Sulfate depositional fluxes of individual volcanic events vary greatly among the different cores. A volcanic flux normalization (volcanic flux/Tambora flux ratio) was used to evaluate the relative intensity of the same event recorded at different sites in the last millennium. Normalized flux variability for the same event showed the highest value in the 1100–1500 AD period. This pattern could mirror changes in regional transport linked to climatic variations such as slight warming stages in the Southern Hemisphere (Southern Hemisphere Medieval Warming–like period?).",
    url = "https://doi.org/10.1029/2004jd005259",
    doi = "10.1029/2004jd005259",
    openalex = "W2040346799",
    references = "doi101029jc087ic06p04301"
}

Abstract We investigate and quantify the variability of snow accumulation rate around a medium-depth firn core (160 m) drilled in east Dronning Maud Land, Antarctica (75°00′ S, 15°00’ E; 3470 m h.a.e. (ellipsoidal height)). We present accumulation data from five snow pits and five shallow (20 m) firn cores distributed within a 3.5–7 km distance, retrieved during the 2000/01 Nordic EPICA (European Project for Ice Coring in Antarctica) traverse. Snow accumulation rates estimated for shorter periods show higher spatial variance than for longer periods. Accumulation variability as recorded from the firn cores and snow pits cannot explain all the variation in the ion and isotope time series; other depositional and post-depositional processes need to be accounted for. Through simple statistical analysis we show that there are differences in sensitivity to these processes between the analyzed species. Oxygen isotopes and sulphate are more conservative in their post-depositional behaviour than the more volatile acids, such as nitrate and to some degree chloride and methanesulphonic acid. We discuss the possible causes for the accumulation variability and the implications for the interpretation of ice-core records.

@article{doi103189172756505781829232,
    author = "Karlöf, Lars and Isaksson, Elisabeth and Winther, Jan‐Gunnar and Gundestrup, N. and Meijer, Harro A. J. and Mulvaney, Robert and Pourchet, M. and Hofstede, Coen and Lappegard, Gaute and Pettersson, Rickard and van den Broeke, M. R. and van de Wal, Roderik S. W.",
    title = "Accumulation variability over a small area in east Dronning Maud Land, Antarctica, as determined from shallow firn cores and snow pits: some implications for ice-core records",
    year = "2005",
    journal = "Journal of Glaciology",
    abstract = "Abstract We investigate and quantify the variability of snow accumulation rate around a medium-depth firn core (160 m) drilled in east Dronning Maud Land, Antarctica (75°00′ S, 15°00’ E; 3470 m h.a.e. (ellipsoidal height)). We present accumulation data from five snow pits and five shallow (20 m) firn cores distributed within a 3.5–7 km distance, retrieved during the 2000/01 Nordic EPICA (European Project for Ice Coring in Antarctica) traverse. Snow accumulation rates estimated for shorter periods show higher spatial variance than for longer periods. Accumulation variability as recorded from the firn cores and snow pits cannot explain all the variation in the ion and isotope time series; other depositional and post-depositional processes need to be accounted for. Through simple statistical analysis we show that there are differences in sensitivity to these processes between the analyzed species. Oxygen isotopes and sulphate are more conservative in their post-depositional behaviour than the more volatile acids, such as nitrate and to some degree chloride and methanesulphonic acid. We discuss the possible causes for the accumulation variability and the implications for the interpretation of ice-core records.",
    url = "https://doi.org/10.3189/172756505781829232",
    doi = "10.3189/172756505781829232",
    openalex = "W2138853565",
    references = "doi101017cbo9780511524967, doi101017s0022143000002021, doi101017s002214300001385x, doi101017s0022143000015227, doi101017s0260305500005942, doi10102997jd01394, doi101111j215334901964tb00181x, doi1011751520046920020593117mbotea20co2, doi103189172756400781820705, doi103402tellusav16i48993, doi105860choice355090"
}

Air mass trajectories in the Southern Hemisphere provide a mechanism for transport to and deposition of volcanic products on the Antarctic ice sheet from local volcanoes and from tropical and subtropical volcanic centers. This study extends the detailed record of Antarctic, South American, and equatorial volcanism over the last 12,000 years using continuous glaciochemical series developed from the Siple Dome A (SDMA) ice core, West Antarctica. The largest volcanic sulfate spike (280 μg/L) occurs at 5881 B.C.E. Other large signals with unknown sources are observed around 325 B.C.E. (270 μg/L) and 2818 B.C.E. (191 μg/L). Ages of several large equatorial or Southern Hemisphere volcanic eruptions are synchronous with many sulfate peaks detected in the SDMA volcanic ice chemistry record. The microprobe “fingerprinting” of glass shards in the SDMA core points to the following Antarctic volcanic centers as sources of tephra found in the SDMA core: Balenny Island, Pleiades, Mount Berlin, Mount Takahe, and Mount Melbourne as well as Mount Hudson and possibly Mount Burney volcanoes of South America. Identified volcanic sources provide an insight into the poorly resolved transport history of volcanic products from source volcanoes to the West Antarctic ice sheet.

@article{doi1010292005jd006072,
    author = "Kurbatov, Andrei V. and Zielinski, Gregory A. and Dunbar, Nelia and Mayewski, Paul A. and Meyerson, E. A. and Sneed, Sharon B. and Taylor, K. C.",
    title = "A 12,000 year record of explosive volcanism in the Siple Dome Ice Core, West Antarctica",
    year = "2006",
    journal = "Journal of Geophysical Research Atmospheres",
    abstract = "Air mass trajectories in the Southern Hemisphere provide a mechanism for transport to and deposition of volcanic products on the Antarctic ice sheet from local volcanoes and from tropical and subtropical volcanic centers. This study extends the detailed record of Antarctic, South American, and equatorial volcanism over the last 12,000 years using continuous glaciochemical series developed from the Siple Dome A (SDMA) ice core, West Antarctica. The largest volcanic sulfate spike (280 μg/L) occurs at 5881 B.C.E. Other large signals with unknown sources are observed around 325 B.C.E. (270 μg/L) and 2818 B.C.E. (191 μg/L). Ages of several large equatorial or Southern Hemisphere volcanic eruptions are synchronous with many sulfate peaks detected in the SDMA volcanic ice chemistry record. The microprobe “fingerprinting” of glass shards in the SDMA core points to the following Antarctic volcanic centers as sources of tephra found in the SDMA core: Balenny Island, Pleiades, Mount Berlin, Mount Takahe, and Mount Melbourne as well as Mount Hudson and possibly Mount Burney volcanoes of South America. Identified volcanic sources provide an insight into the poorly resolved transport history of volcanic products from source volcanoes to the West Antarctic ice sheet.",
    url = "https://doi.org/10.1029/2005jd006072",
    doi = "10.1029/2005jd006072",
    openalex = "W2147027563",
    references = "doi1010292000gl011499, kyle1981tephra"
}

We report new century‐scale ice core records of hydrogen peroxide (H 2 O 2), a major atmospheric oxidant, from 23 locations across the West Antarctic Ice Sheet (WAIS) and use the spatial variability of (multi‐) annual mean H 2 O 2 concentrations in snow and firn to investigate the sensitivity of ice core H 2 O 2 preservation to mean annual temperature and accumulation rate. In agreement with the ice‐air equilibrium partitioning, H 2 O 2 uptake in near‐surface firn was found to be greatest at low temperatures, while postdepositional losses from degassing increase as accumulation rates decrease. This resulted in almost complete loss of H 2 O 2 at warm (>−25°C), low‐accumulation sites (94% deviations from the ice‐air equilibrium at high‐accumulation sites (>30 cm yr −1), but close‐to‐equilibrium values on the East Antarctic Plateau, where it is dry (0.6, p 30 cm yr −1) are most suitable for detection of temporal changes in atmospheric concentration, although a long‐term H 2 O 2 record will be well preserved under the current environment at the WAIS Divide core site.

@article{doi1010292005jd006816,
    author = "Frey, M. M. and Bales, Roger C. and McConnell, Joseph R.",
    title = "Climate sensitivity of the century‐scale hydrogen peroxide (H 2 O 2) record preserved in 23 ice cores from West Antarctica",
    year = "2006",
    journal = "Journal of Geophysical Research Atmospheres",
    abstract = "We report new century‐scale ice core records of hydrogen peroxide (H 2 O 2), a major atmospheric oxidant, from 23 locations across the West Antarctic Ice Sheet (WAIS) and use the spatial variability of (multi‐) annual mean H 2 O 2 concentrations in snow and firn to investigate the sensitivity of ice core H 2 O 2 preservation to mean annual temperature and accumulation rate. In agreement with the ice‐air equilibrium partitioning, H 2 O 2 uptake in near‐surface firn was found to be greatest at low temperatures, while postdepositional losses from degassing increase as accumulation rates decrease. This resulted in almost complete loss of H 2 O 2 at warm (>−25°C), low‐accumulation sites (94\% deviations from the ice‐air equilibrium at high‐accumulation sites (>30 cm yr −1), but close‐to‐equilibrium values on the East Antarctic Plateau, where it is dry (0.6, p 30 cm yr −1) are most suitable for detection of temporal changes in atmospheric concentration, although a long‐term H 2 O 2 record will be well preserved under the current environment at the WAIS Divide core site.",
    url = "https://doi.org/10.1029/2005jd006816",
    doi = "10.1029/2005jd006816",
    openalex = "W2086806785",
    references = "doi1010292000gl011499"
}

Abstract We use an airborne‐radar method, verified with ice‐core accumulation records, to determine the spatiotemporal variations of snow accumulation over Thwaites Glacier, West Antarctica between 1980 and 2009. We also present a regional evaluation of modeled accumulation in Antarctica. Comparisons between radar‐derived measurements and model outputs show that three global models capture the interannual variability well (r > 0.9), but a high‐resolution regional model (RACMO2) has better absolute accuracy and captures the observed spatial variability (r = 0.86). Neither the measured nor modeled accumulation records over Thwaites Glacier show any trend since 1980. Although an increase in accumulation may potentially accompany the observed warming in the region, the projected trend is too small to detect over the 30 year record.

@article{doi101002grl50706,
    author = "Medley, Brooke and Joughin, Ian and Das, Sarah B. and Steig, Eric J. and Conway, H. and Gogineni, S. and Criscitiello, Alison S. and McConnell, Joseph R. and Smith, B. E. and van den Broeke, M. R. and Lenaerts, Jan T. M. and Bromwich, David H. and Nicolas, Julien P.",
    title = "Airborne‐radar and ice‐core observations of annual snow accumulation over Thwaites Glacier, West Antarctica confirm the spatiotemporal variability of global and regional atmospheric models",
    year = "2013",
    journal = "Geophysical Research Letters",
    abstract = "Abstract We use an airborne‐radar method, verified with ice‐core accumulation records, to determine the spatiotemporal variations of snow accumulation over Thwaites Glacier, West Antarctica between 1980 and 2009. We also present a regional evaluation of modeled accumulation in Antarctica. Comparisons between radar‐derived measurements and model outputs show that three global models capture the interannual variability well (r > 0.9), but a high‐resolution regional model (RACMO2) has better absolute accuracy and captures the observed spatial variability (r = 0.86). Neither the measured nor modeled accumulation records over Thwaites Glacier show any trend since 1980. Although an increase in accumulation may potentially accompany the observed warming in the region, the projected trend is too small to detect over the 30 year record.",
    url = "https://doi.org/10.1002/grl.50706",
    doi = "10.1002/grl.50706",
    openalex = "W2140351612",
    references = "doi103189172756404781814393"
}

Abstract. The spatial and temporal distribution of surface mass balance (SMB) and δ18O were investigated in the first comprehensive study of a set of 76 firn cores retrieved by various expeditions during the past 3 decades in Dronning Maud Land, East Antarctica. The large number of cores was used to calculate stacked records of SMB and δ18O, which considerably increased the signal-to-noise ratio compared to earlier studies and facilitated the detection of climatic signals. Considerable differences between cores from the interior plateau and the coastal cores were found. The δ18O of both the plateau and the ice shelf cores exhibit a slight positive trend over the second half of the 20th century. In the corresponding period, the SMB has a negative trend in the ice shelf cores, but increases on the plateau. Comparison with meteorological data from Neumayer Station revealed that for the ice shelf regions, atmospheric dynamic effects are more important than thermodynamics while on the plateau; the temporal variations of SMB and δ18O occur mostly in parallel, and thus can be explained by thermodynamic effects. The Southern Annular Mode (SAM) has exhibited a positive trend since the mid-1960s, which is assumed to lead to a cooling of East Antarctica. This is not confirmed by the firn core data in our data set. Changes in the atmospheric circulation that result in a changed seasonal distribution of precipitation/accumulation could partly explain the observed features in the ice shelf cores.

@article{doi105194tc99252015,
    author = "Altnau, S. and Schlosser, Elisabeth and Isaksson, Elisabeth and Divine, Dmitry",
    title = "Climatic signals from 76 shallow firn cores in Dronning Maud Land, East Antarctica",
    year = "2015",
    journal = "˜The œcryosphere",
    abstract = "Abstract. The spatial and temporal distribution of surface mass balance (SMB) and δ18O were investigated in the first comprehensive study of a set of 76 firn cores retrieved by various expeditions during the past 3 decades in Dronning Maud Land, East Antarctica. The large number of cores was used to calculate stacked records of SMB and δ18O, which considerably increased the signal-to-noise ratio compared to earlier studies and facilitated the detection of climatic signals. Considerable differences between cores from the interior plateau and the coastal cores were found. The δ18O of both the plateau and the ice shelf cores exhibit a slight positive trend over the second half of the 20th century. In the corresponding period, the SMB has a negative trend in the ice shelf cores, but increases on the plateau. Comparison with meteorological data from Neumayer Station revealed that for the ice shelf regions, atmospheric dynamic effects are more important than thermodynamics while on the plateau; the temporal variations of SMB and δ18O occur mostly in parallel, and thus can be explained by thermodynamic effects. The Southern Annular Mode (SAM) has exhibited a positive trend since the mid-1960s, which is assumed to lead to a cooling of East Antarctica. This is not confirmed by the firn core data in our data set. Changes in the atmospheric circulation that result in a changed seasonal distribution of precipitation/accumulation could partly explain the observed features in the ice shelf cores.",
    url = "https://doi.org/10.5194/tc-9-925-2015",
    doi = "10.5194/tc-9-925-2015",
    openalex = "W2051710176",
    references = "doi103189172756505781829232, doi1031891998aog271231238"
}

Abstract. Ice cores provide temporal records of surface mass balance (SMB). Coastal areas of Antarctica have relatively high and variable SMB, but are under-represented in records spanning more than 100 years. Here we present SMB reconstruction from a 120 m-long ice core drilled in 2012 on the Derwael Ice Rise, coastal Dronning Maud Land, East Antarctica. Water stable isotope (δ18O and δD) stratigraphy is supplemented by discontinuous major ion profiles and continuous electrical conductivity measurements. The base of the ice core is dated to AD 1759 ± 16, providing a climate proxy for the past ∼ 250 years. The core's annual layer thickness history is combined with its gravimetric density profile to reconstruct the site's SMB history, corrected for the influence of ice deformation. The mean SMB for the core's entire history is 0.47 ± 0.02 m water equivalent (w.e.) a−1. The time series of reconstructed annual SMB shows high variability, but a general increase beginning in the 20th century. This increase is particularly marked during the last 50 years (1962–2011), which yields mean SMB of 0.61 ± 0.01 m w.e. a−1. This trend is compared with other reported SMB data in Antarctica, generally showing a high spatial variability. Output of the fully coupled Community Earth System Model (CESM) suggests that, although atmospheric circulation is the main factor influencing SMB, variability in sea surface temperatures and sea ice cover in the precipitation source region also explain part of the variability in SMB. Local snow redistribution can also influence interannual variability but is unlikely to influence long-term trends significantly. This is the first record from a coastal ice core in East Antarctica to show an increase in SMB beginning in the early 20th century and particularly marked during the last 50 years.

@article{doi105194tc1025012016,
    author = "Philippe, Morgane and Tison, Jean‐Louis and Fjøsne, Karen and Hubbard, Bryn and Kjær, Helle Astrid and Lenaerts, Jan T. M. and Drews, Reinhard and Sheldon, Simon G. and Bondt, Kevin De and Claeys, Philippe and Pattyn, Frank",
    title = "Ice core evidence for a 20th century increase in surface mass balance in coastal Dronning Maud Land, East Antarctica",
    year = "2016",
    journal = "˜The œcryosphere",
    abstract = "Abstract. Ice cores provide temporal records of surface mass balance (SMB). Coastal areas of Antarctica have relatively high and variable SMB, but are under-represented in records spanning more than 100 years. Here we present SMB reconstruction from a 120 m-long ice core drilled in 2012 on the Derwael Ice Rise, coastal Dronning Maud Land, East Antarctica. Water stable isotope (δ18O and δD) stratigraphy is supplemented by discontinuous major ion profiles and continuous electrical conductivity measurements. The base of the ice core is dated to AD 1759 ± 16, providing a climate proxy for the past ∼ 250 years. The core's annual layer thickness history is combined with its gravimetric density profile to reconstruct the site's SMB history, corrected for the influence of ice deformation. The mean SMB for the core's entire history is 0.47 ± 0.02 m water equivalent (w.e.) a−1. The time series of reconstructed annual SMB shows high variability, but a general increase beginning in the 20th century. This increase is particularly marked during the last 50 years (1962–2011), which yields mean SMB of 0.61 ± 0.01 m w.e. a−1. This trend is compared with other reported SMB data in Antarctica, generally showing a high spatial variability. Output of the fully coupled Community Earth System Model (CESM) suggests that, although atmospheric circulation is the main factor influencing SMB, variability in sea surface temperatures and sea ice cover in the precipitation source region also explain part of the variability in SMB. Local snow redistribution can also influence interannual variability but is unlikely to influence long-term trends significantly. This is the first record from a coastal ice core in East Antarctica to show an increase in SMB beginning in the early 20th century and particularly marked during the last 50 years.",
    url = "https://doi.org/10.5194/tc-10-2501-2016",
    doi = "10.5194/tc-10-2501-2016",
    openalex = "W2536097380",
    references = "doi103189172756505781829232"
}

Abstract. Three shallow firn cores were retrieved in the austral summers of 2011/12 and 2013/14 on the ice rises Kupol Ciolkovskogo (KC), Kupol Moskovskij (KM), and Blåskimen Island (BI), all part of Fimbul Ice Shelf (FIS) in western Dronning Maud Land (DML), Antarctica. The cores were dated back to 1958 (KC), 1995 (KM), and 1996 (BI) by annual layer counting using high-resolution oxygen isotope (δ18O) data, and by identifying volcanic horizons using non-sea-salt sulfate (nssSO42−) data. The water stable isotope records show that the atmospheric signature of the annual snow accumulation cycle is well preserved in the firn column, especially at KM and BI. We are able to determine the annual surface mass balance (SMB), as well as the mean SMB values between identified volcanic horizons. Average SMB at the KM and BI sites (0.68 and 0.70 mw. e. yr−1) was higher than at the KC site (0.24 mw. e. yr−1), and there was greater temporal variability as well. Trends in the SMB and δ18O records from the KC core over the period of 1958–2012 agree well with other previously investigated cores in the area, thus the KC site could be considered the most representative of the climate of the region. Cores from KM and BI appear to be more affected by local meteorological conditions and surface topography. Our results suggest that the ice rises are suitable sites for the retrieval of longer firn and ice cores, but that BI has the best preserved seasonal cycles of the three records and is thus the most optimal site for high-resolution studies of temporal variability of the climate signal. Deuterium excess data suggest a possible effect of seasonal moisture transport changes on the annual isotopic signal. In agreement with previous studies, large-scale atmospheric circulation patterns most likely provide the dominant influence on water stable isotope ratios preserved at the core sites.

@article{doi105194tc1027632016,
    author = "Vega, Carmen P. and Schlosser, Elisabeth and Divine, Dmitry and Kohler, Jack and Martma, Tõnu and Eichler, Anja and Schwikowski, Margit and Isaksson, Elisabeth",
    title = "Surface mass balance and water stable isotopes derived from firn cores on three ice rises, Fimbul Ice Shelf, Antarctica",
    year = "2016",
    journal = "˜The œcryosphere",
    abstract = "Abstract. Three shallow firn cores were retrieved in the austral summers of 2011/12 and 2013/14 on the ice rises Kupol Ciolkovskogo (KC), Kupol Moskovskij (KM), and Blåskimen Island (BI), all part of Fimbul Ice Shelf (FIS) in western Dronning Maud Land (DML), Antarctica. The cores were dated back to 1958 (KC), 1995 (KM), and 1996 (BI) by annual layer counting using high-resolution oxygen isotope (δ18O) data, and by identifying volcanic horizons using non-sea-salt sulfate (nssSO42−) data. The water stable isotope records show that the atmospheric signature of the annual snow accumulation cycle is well preserved in the firn column, especially at KM and BI. We are able to determine the annual surface mass balance (SMB), as well as the mean SMB values between identified volcanic horizons. Average SMB at the KM and BI sites (0.68 and 0.70 mw. e. yr−1) was higher than at the KC site (0.24 mw. e. yr−1), and there was greater temporal variability as well. Trends in the SMB and δ18O records from the KC core over the period of 1958–2012 agree well with other previously investigated cores in the area, thus the KC site could be considered the most representative of the climate of the region. Cores from KM and BI appear to be more affected by local meteorological conditions and surface topography. Our results suggest that the ice rises are suitable sites for the retrieval of longer firn and ice cores, but that BI has the best preserved seasonal cycles of the three records and is thus the most optimal site for high-resolution studies of temporal variability of the climate signal. Deuterium excess data suggest a possible effect of seasonal moisture transport changes on the annual isotopic signal. In agreement with previous studies, large-scale atmospheric circulation patterns most likely provide the dominant influence on water stable isotope ratios preserved at the core sites.",
    url = "https://doi.org/10.5194/tc-10-2763-2016",
    doi = "10.5194/tc-10-2763-2016",
    openalex = "W2467597135",
    references = "doi1031891998aog271231238"
}

Abstract. Ice cores provide temporal records of snow accumulation, a crucial component of Antarctic mass balance. Coastal areas are particularly under-represented in such records, despite their relatively high and sensitive accumulation rates. Here we present records from a 120 m ice core drilled on Derwael Ice Rise, coastal Dronning Maud Land (DML), East Antarctica in 2012. We date the ice core bottom back to 1745 ± 2 AD. δ18O and δD stratigraphy is supplemented by discontinuous major ion profiles, and verified independently by electrical conductivity measurements (ECM) to detect volcanic horizons. The resulting annual layer history is combined with the core density profile to calculate accumulation history, corrected for the influence of ice deformation. The mean long-term accumulation is 0.425 ± 0.035 m water equivalent (w.e.) a−1 (average corrected value). Reconstructed annual accumulation rates show an increase from 1955 onward to a mean value of 0.61 ± 0.02 m w.e. a−1 between 1955 and 2012. This trend is compared to other reported accumulation data in Antarctica, generally showing a high spatial variability. Output of the fully coupled Community Earth System Model demonstrates that sea ice and atmospheric patterns largely explain the accumulation variability. This is the first and longest record from a coastal ice core in East Antarctica showing a steady increase during the 20th and 21st centuries, thereby supporting modelling predictions.

@article{doi105194tc201627,
    author = "Philippe, Morgane and Tison, Jean‐Louis and Fjøsne, Karen and Hubbard, Bryn and Kjær, Helle Astrid and Lenaerts, Jan T. M. and Sheldon, Simon G. and Bondt, Kevin De and Claeys, Philippe and Pattyn, Frank",
    title = "Ice core evidence for a recent increase in snow accumulation in coastal Dronning Maud Land, East Antarctica",
    year = "2016",
    abstract = "Abstract. Ice cores provide temporal records of snow accumulation, a crucial component of Antarctic mass balance. Coastal areas are particularly under-represented in such records, despite their relatively high and sensitive accumulation rates. Here we present records from a 120 m ice core drilled on Derwael Ice Rise, coastal Dronning Maud Land (DML), East Antarctica in 2012. We date the ice core bottom back to 1745 ± 2 AD. δ18O and δD stratigraphy is supplemented by discontinuous major ion profiles, and verified independently by electrical conductivity measurements (ECM) to detect volcanic horizons. The resulting annual layer history is combined with the core density profile to calculate accumulation history, corrected for the influence of ice deformation. The mean long-term accumulation is 0.425 ± 0.035 m water equivalent (w.e.) a−1 (average corrected value). Reconstructed annual accumulation rates show an increase from 1955 onward to a mean value of 0.61 ± 0.02 m w.e. a−1 between 1955 and 2012. This trend is compared to other reported accumulation data in Antarctica, generally showing a high spatial variability. Output of the fully coupled Community Earth System Model demonstrates that sea ice and atmospheric patterns largely explain the accumulation variability. This is the first and longest record from a coastal ice core in East Antarctica showing a steady increase during the 20th and 21st centuries, thereby supporting modelling predictions.",
    url = "https://doi.org/10.5194/tc-2016-27",
    doi = "10.5194/tc-2016-27",
    openalex = "W2291947052",
    references = "doi103189172756505781829232, doi103189s0022143000028367"
}

Abstract. We present a compilation of radio-echo sounding (RES) measurements of five radar systems (AWI, BAS, CReSIS, INGV and UTIG) around the EPICA Dome C (EDC) drill site, East Antarctica. The aim of our study is to investigate the differences of the various systems in their resolution of internal reflection horizons (IRHs) and bed topography, penetration depth and capacity of imaging the basal layer. We address the questions of the compatibility of existing radar data for common interpretation and the suitability of the individual systems for reconnaissance surveys. We find that the most distinct IRHs and IRH patterns can be identified and transferred between most data sets. Considerable differences between the RES systems exist in range resolution and depiction of the bottom-most region. Considering both aspects, which we judge as crucial factors in the search for old ice, the CReSIS and the UTIG systems are the most suitable ones. In addition to the RES data set comparison we calculate a synthetic radar trace from EDC density and conductivity profiles. We identify 10 common IRHs in the measured RES data and the synthetic trace. We then conduct a sensitivity study for which we remove certain peaks from the input conductivity profile. As a result the respective reflections disappear from the modeled radar trace. In this way, we establish a depth conversion of the measured travel times of the IRHs. Furthermore, we use these sensitivity studies to investigate the cause of observed reflections. The identified IRHs are assigned ages from the EDC's timescale. Due to the isochronous character of these conductivity-caused IRHs, they are a means to extend the Dome C age structure by tracing the IRHs along the RES profiles.

@article{doi105194tc116532017,
    author = "Winter, Anna and Steinhage, Daniel and Arnold, Emily and Blankenship, Donald D. and Cavitte, Marie G. P. and Corr, Hugh F. J. and Paden, John and Urbini, Stefano and Young, D. A. and Eisen, Olaf",
    title = "Comparison of measurements from different radio-echo sounding systems and synchronization with the ice core at Dome C, Antarctica",
    year = "2017",
    journal = "˜The œcryosphere",
    abstract = "Abstract. We present a compilation of radio-echo sounding (RES) measurements of five radar systems (AWI, BAS, CReSIS, INGV and UTIG) around the EPICA Dome C (EDC) drill site, East Antarctica. The aim of our study is to investigate the differences of the various systems in their resolution of internal reflection horizons (IRHs) and bed topography, penetration depth and capacity of imaging the basal layer. We address the questions of the compatibility of existing radar data for common interpretation and the suitability of the individual systems for reconnaissance surveys. We find that the most distinct IRHs and IRH patterns can be identified and transferred between most data sets. Considerable differences between the RES systems exist in range resolution and depiction of the bottom-most region. Considering both aspects, which we judge as crucial factors in the search for old ice, the CReSIS and the UTIG systems are the most suitable ones. In addition to the RES data set comparison we calculate a synthetic radar trace from EDC density and conductivity profiles. We identify 10 common IRHs in the measured RES data and the synthetic trace. We then conduct a sensitivity study for which we remove certain peaks from the input conductivity profile. As a result the respective reflections disappear from the modeled radar trace. In this way, we establish a depth conversion of the measured travel times of the IRHs. Furthermore, we use these sensitivity studies to investigate the cause of observed reflections. The identified IRHs are assigned ages from the EDC's timescale. Due to the isochronous character of these conductivity-caused IRHs, they are a means to extend the Dome C age structure by tracing the IRHs along the RES profiles.",
    url = "https://doi.org/10.5194/tc-11-653-2017",
    doi = "10.5194/tc-11-653-2017",
    openalex = "W2592168624",
    references = "doi1010291998jd200082"
}

Abstract. Major ions were analysed in firn and ice cores located at Fimbul Ice Shelf (FIS), Dronning Maud Land – DML, Antarctica. FIS is the largest ice shelf in the Haakon VII Sea, with an extent of approximately 36 500 km2. Three shallow firn cores (about 20 m deep) were retrieved in different ice rises, Kupol Ciolkovskogo (KC), Kupol Moskovskij (KM), and Blåskimen Island (BI), while a 100 m long core (S100) was drilled near the FIS edge. These sites are distributed over the entire FIS area so that they provide a variety of elevation (50–400 m a.s.l.) and distance (3–42 km) to the sea. Sea-salt species (mainly Na+ and Cl−) generally dominate the precipitation chemistry in the study region. We associate a significant sixfold increase in median sea-salt concentrations, observed in the S100 core after the 1950s, to an enhanced exposure of the S100 site to primary sea-salt aerosol due to a shorter distance from the S100 site to the ice front, and to enhanced sea-salt aerosol production from blowing salty snow over sea ice, most likely related to the calving of Trolltunga occurred during the 1960s. This increase in sea-salt concentrations is synchronous with a shift in non-sea-salt sulfate (nssSO42−) toward negative values, suggesting a possible contribution of fractionated aerosol to the sea-salt load in the S100 core most likely originating from salty snow found on sea ice. In contrast, there is no evidence of a significant contribution of fractionated sea salt to the ice-rises sites, where the signal would be most likely masked by the large inputs of biogenic sulfate estimated for these sites. In summary, these results suggest that the S100 core contains a sea-salt record dominated by the proximity of the site to the ocean, and processes of sea ice formation in the neighbouring waters. In contrast, the ice-rises firn cores register a larger-scale signal of atmospheric flow conditions and a less efficient transport of sea-salt aerosols to these sites. These findings are a contribution to the understanding of the mechanisms behind sea-salt aerosol production, transport and deposition at coastal Antarctic sites, and the improvement of the current Antarctic sea ice reconstructions based on sea-salt chemical proxies obtained from ice cores.

@article{doi105194tc1216812018,
    author = "Vega, Carmen P. and Isaksson, Elisabeth and Schlosser, Elisabeth and Divine, Dmitry and Martma, Tõnu and Mulvaney, Robert and Eichler, Anja and Schwikowski, Margit",
    title = "Variability of sea salts in ice and firn cores from Fimbul Ice Shelf, Dronning Maud Land, Antarctica",
    year = "2018",
    journal = "˜The œcryosphere",
    abstract = "Abstract. Major ions were analysed in firn and ice cores located at Fimbul Ice Shelf (FIS), Dronning Maud Land – DML, Antarctica. FIS is the largest ice shelf in the Haakon VII Sea, with an extent of approximately 36 500 km2. Three shallow firn cores (about 20 m deep) were retrieved in different ice rises, Kupol Ciolkovskogo (KC), Kupol Moskovskij (KM), and Blåskimen Island (BI), while a 100 m long core (S100) was drilled near the FIS edge. These sites are distributed over the entire FIS area so that they provide a variety of elevation (50–400 m a.s.l.) and distance (3–42 km) to the sea. Sea-salt species (mainly Na+ and Cl−) generally dominate the precipitation chemistry in the study region. We associate a significant sixfold increase in median sea-salt concentrations, observed in the S100 core after the 1950s, to an enhanced exposure of the S100 site to primary sea-salt aerosol due to a shorter distance from the S100 site to the ice front, and to enhanced sea-salt aerosol production from blowing salty snow over sea ice, most likely related to the calving of Trolltunga occurred during the 1960s. This increase in sea-salt concentrations is synchronous with a shift in non-sea-salt sulfate (nssSO42−) toward negative values, suggesting a possible contribution of fractionated aerosol to the sea-salt load in the S100 core most likely originating from salty snow found on sea ice. In contrast, there is no evidence of a significant contribution of fractionated sea salt to the ice-rises sites, where the signal would be most likely masked by the large inputs of biogenic sulfate estimated for these sites. In summary, these results suggest that the S100 core contains a sea-salt record dominated by the proximity of the site to the ocean, and processes of sea ice formation in the neighbouring waters. In contrast, the ice-rises firn cores register a larger-scale signal of atmospheric flow conditions and a less efficient transport of sea-salt aerosols to these sites. These findings are a contribution to the understanding of the mechanisms behind sea-salt aerosol production, transport and deposition at coastal Antarctic sites, and the improvement of the current Antarctic sea ice reconstructions based on sea-salt chemical proxies obtained from ice cores.",
    url = "https://doi.org/10.5194/tc-12-1681-2018",
    doi = "10.5194/tc-12-1681-2018",
    openalex = "W2803295041",
    references = "doi1031891998aog271231238"
}

Major explosive volcanic eruptions may significantly alter the global atmosphere for about 2–3 years. During that period, volcanic products (mainly H2SO4) with high residence time, stored in the stratosphere or, for shorter times, in the troposphere are gradually deposited onto polar ice caps. Antarctic snow may thus record acidic signals providing a history of past volcanic events. The high resolution sulphate concentration profile along a 197 m long ice core drilled at GV7 (Northern Victoria land) was obtained by Ion Chromatography on around 3500 discrete samples. The relatively high accumulation rate (241 ± 13 mm we yr −1) and the 5-cm sampling resolution allowed a preliminary counted age scale. The obtained stratigraphy covers roughly the last millennium and 24 major volcanic eruptions were identified, dated, and tentatively ascribed to a source volcano. The deposition flux of volcanic sulphate was calculated for each signature and the results were compared with data from other Antarctic ice cores at regional and continental scale. Our results show that the regional variability is of the same order of magnitude as the continental one.

@article{doi103390geosciences10010038,
    author = "Nardin, Raffaello and Amore, Alessandra and Becagli, Silvia and Caiazzo, Laura and Frezzotti, Massimo and Severi, Mirko and Stenni, Barbara and Traversi, Rita",
    title = "Volcanic Fluxes Over the Last Millennium as Recorded in the Gv7 Ice Core (Northern Victoria Land, Antarctica)",
    year = "2020",
    journal = "Geosciences",
    abstract = "Major explosive volcanic eruptions may significantly alter the global atmosphere for about 2–3 years. During that period, volcanic products (mainly H2SO4) with high residence time, stored in the stratosphere or, for shorter times, in the troposphere are gradually deposited onto polar ice caps. Antarctic snow may thus record acidic signals providing a history of past volcanic events. The high resolution sulphate concentration profile along a 197 m long ice core drilled at GV7 (Northern Victoria land) was obtained by Ion Chromatography on around 3500 discrete samples. The relatively high accumulation rate (241 ± 13 mm we yr −1) and the 5-cm sampling resolution allowed a preliminary counted age scale. The obtained stratigraphy covers roughly the last millennium and 24 major volcanic eruptions were identified, dated, and tentatively ascribed to a source volcano. The deposition flux of volcanic sulphate was calculated for each signature and the results were compared with data from other Antarctic ice cores at regional and continental scale. Our results show that the regional variability is of the same order of magnitude as the continental one.",
    url = "https://doi.org/10.3390/geosciences10010038",
    doi = "10.3390/geosciences10010038",
    openalex = "W3000505241",
    references = "doi101029jd090id07p12901"
}

Provenance records from sediments deposited offshore of the West Antarctic Ice Sheet (WAIS) can help identify past major ice retreat, thus constraining ice‐sheet models projecting future sea‐level rise. Interpretations from such records are, however, hampered by the ice obscuring Antarctica's geology. Here, we explore central West Antarctica's subglacial geology using basal debris from within the Byrd ice core, drilled to the bed in 1968. Sand grain microtextures and a high kaolinite content (∼38–42%) reveal the debris consists predominantly of eroded sedimentary detritus, likely deposited initially in a warm, pre‐Oligocene, subaerial environment. Detrital hornblende 40 Ar/ 39 Ar ages suggest proximal late Cenozoic subglacial volcanism. The debris has a distinct provenance signature, with: common Permian‐Early Jurassic mineral grains; absent early Ross Orogeny grains; a high kaolinite content; and high 143 Nd/ 144 Nd and low 87 Sr/ 86 Sr ratios. Detecting this “fingerprint” in Antarctic sedimentary records could imply major WAIS retreat, revealing the WAIS's sensitivity to future warming.

@article{marschalek2024byrd,
    author = "Marschalek, J. W. and Blard, P.‐H. and Sarigulyan, E. and Ehrmann, W. and Hemming, S. R. and Thomson, S. N. and Hillenbrand, C.‐D. and Licht, K. and Tison, J.‐L. and Ardoin, L. and Fripiat, F. and Allen, C. S. and Marrocchi, Y. and Siegert, M. J. and van de Flierdt, T.",
    title = "Byrd Ice Core Debris Constrains the Sediment Provenance Signature of Central West Antarctica",
    year = "2024",
    journal = "Geophysical Research Letters",
    abstract = "Provenance records from sediments deposited offshore of the West Antarctic Ice Sheet (WAIS) can help identify past major ice retreat, thus constraining ice‐sheet models projecting future sea‐level rise. Interpretations from such records are, however, hampered by the ice obscuring Antarctica's geology. Here, we explore central West Antarctica's subglacial geology using basal debris from within the Byrd ice core, drilled to the bed in 1968. Sand grain microtextures and a high kaolinite content (∼38–42\%) reveal the debris consists predominantly of eroded sedimentary detritus, likely deposited initially in a warm, pre‐Oligocene, subaerial environment. Detrital hornblende 40 Ar/ 39 Ar ages suggest proximal late Cenozoic subglacial volcanism. The debris has a distinct provenance signature, with: common Permian‐Early Jurassic mineral grains; absent early Ross Orogeny grains; a high kaolinite content; and high 143 Nd/ 144 Nd and low 87 Sr/ 86 Sr ratios. Detecting this “fingerprint” in Antarctic sedimentary records could imply major WAIS retreat, revealing the WAIS's sensitivity to future warming.",
    url = "https://doi.org/10.1029/2023gl106958",
    doi = "10.1029/2023gl106958",
    number = "5",
    openalex = "W4392624073",
    volume = "51",
    references = "doi1010160012821x80901259, doi101016jchemgeo201204021, doi101016jgsf201804001, doi101016s0009254100001984, doi101016s0009254183800266, doi1010292007gc001805, doi101038nature17145, doi101126science1154339, doi101126science1235798, doi101126science2915501109"
}