Reconnaissance of chemical and isotopic firn properties on top of Berkner Island, Antarctica

The ice cap on Berkner Island is grounded on bedrock within the Filchner-Ronne Ice Shelf and is, therefore, expected to be a well-suited place to retrieve long-term ice-core records reflecting the environmental situation of the Weddell Sea region. Shallow firn cores were drilled to 11 m at the two main summits of Berkner Island and analysed in high depth resolution for electrical d.c. conductivity(ECM), stable isotopes, chloride, sulphate, nitrate and methane-sulphonate (MSA).From the annual layering ofδD and non-sea-salt (nss) sulphate, a mean annual snow accumulation of 26.6 cm water at the north dome and 17.4cm water at the south domeare obtained. As a result of ineffective wind scouring indicated by a relatively lownear-surface snow density, regular annual cycles are found for all species at least in the upper 4-5 m. Post-depositional changes are responsible for a substantial decrease o[the seasonalδD and nitrate amplitude as well as for considerable migration of the MSA signal operating below a depth of 3-4 m. The mean chemical and isotopic firn properties at the south dome correspond to the situation on the Filchner-Ronne Ice Shelf at a comparable distance to the coast, whereas the north dome is found to be much more influenced by maritime air masses. Persistent high sea-salt levels in winter snow at Berkner Island heavily obscure the determination of nss sulphate probably due to sulphate fractionation in the Antarctic sea-salt aerosol. Estimated time-scale spredict ages at 400 m depth to be ~2000 years for the north and ~3000 years for the south dome. Pleistocene ice is expected in the bottom 200 and 300 m, respectively.

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Spatial and seasonal variations of the snow chemistry at the central Filchner-Ronne Ice Shelf, Antarctica

Annals of Glaciology ◽

10.1017/s026030550001658x ◽

1994 ◽

Vol 20 ◽

pp. 283-290 ◽

Cited By ~ 2

Author(s):

Andreas Minikin ◽

Dietmar Wagenbach ◽

Wolfgang Graf ◽

Josef Kipfstuhl

Keyword(s):

Sea Water ◽

Ice Cores ◽

Weddell Sea ◽

Sea Salt ◽

Ice Shelf ◽

Sulphur Compounds ◽

Annual Cycles ◽

Episodic Events ◽

Time Period ◽

Winter Time

The chemical stratigraphy of the surface firn of the central Filchner- Ronne Ice Shelf was determined in conjunction with stable isotopes from shallow firn cores and snow-pit samples collected at 1.1 widely distributed sites, and covering a time period of at least 20 years. The chemical analysis included ECM profiling and the determination of chloride, non-sea-salt (nss) sulphate, methanesulphonate (MSA), nitrate and, partly, sodium and bromide. Throughout the investigated area, winter time nss sulphate levels are found to be substantially negative, indicating that the sulphate to sodium ratio in airborne sea-salt particles is depleted by a factor of 5, approximately, in relation to the bulk sea-water ratio. While winter firn layers appear to be marked by episodic events of large sea-salt inputs, pronounced annual cycles with maxima in summer firn layers are commonly observed for the ECM signal and for nss sulphate, nitrate and MSA at all sites. For MSA, however, this phase relation is almost reversed for depths greater than 3-4m.The mean impurity levels consistently are strongly depleted with increasing distance from the ice edge by about 30% / 100 km for sea salt, 25% / 100 km for MSA and only 10%/ 100 km for nss sulphate. However, no substantial trend is observed for nitrate. It is concluded, therefore, that the sea-salt and the biogenic sulphur compounds deposited on the Filchner-Ronne Ice Shelf mainly originate from the adjacent Weddell Sea.Further important implications of the continental effects are: (a) an atmospheric residence time of nss sulphate apparently exceeding that of MSA probably due to the supplementary sulphate production on the ice shelf from biogenic SO2, and (b) a substantial limitation of the potential of deep ice cores already drilled on the Filchner- Ronne Ice Shelf in extracting reliable net temporal changes of sea-salt and biogenic sulphur species.

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Spatial and seasonal variations of the snow chemistry at the central Filchner-Ronne Ice Shelf, Antarctica

Annals of Glaciology ◽

10.3189/1994aog20-1-283-290 ◽

1994 ◽

Vol 20 ◽

pp. 283-290 ◽

Cited By ~ 5

Author(s):

Andreas Minikin ◽

Dietmar Wagenbach ◽

Wolfgang Graf ◽

Josef Kipfstuhl

Keyword(s):

Sea Water ◽

Ice Cores ◽

Weddell Sea ◽

Sea Salt ◽

Ice Shelf ◽

Sulphur Compounds ◽

Annual Cycles ◽

Episodic Events ◽

Time Period ◽

Winter Time

The chemical stratigraphy of the surface firn of the central Filchner- Ronne Ice Shelf was determined in conjunction with stable isotopes from shallow firn cores and snow-pit samples collected at 1.1 widely distributed sites, and covering a time period of at least 20 years. The chemical analysis included ECM profiling and the determination of chloride, non-sea-salt (nss) sulphate, methanesulphonate (MSA), nitrate and, partly, sodium and bromide. Throughout the investigated area, winter time nss sulphate levels are found to be substantially negative, indicating that the sulphate to sodium ratio in airborne sea-salt particles is depleted by a factor of 5, approximately, in relation to the bulk sea-water ratio. While winter firn layers appear to be marked by episodic events of large sea-salt inputs, pronounced annual cycles with maxima in summer firn layers are commonly observed for the ECM signal and for nss sulphate, nitrate and MSA at all sites. For MSA, however, this phase relation is almost reversed for depths greater than 3-4m.The mean impurity levels consistently are strongly depleted with increasing distance from the ice edge by about 30% / 100 km for sea salt, 25% / 100 km for MSA and only 10%/ 100 km for nss sulphate. However, no substantial trend is observed for nitrate. It is concluded, therefore, that the sea-salt and the biogenic sulphur compounds deposited on the Filchner-Ronne Ice Shelf mainly originate from the adjacent Weddell Sea.Further important implications of the continental effects are: (a) an atmospheric residence time of nss sulphate apparently exceeding that of MSA probably due to the supplementary sulphate production on the ice shelf from biogenic SO2, and (b) a substantial limitation of the potential of deep ice cores already drilled on the Filchner- Ronne Ice Shelf in extracting reliable net temporal changes of sea-salt and biogenic sulphur species.

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Comprehensive 1000 year climatic history from an intermediate-depth ice core from the south dome of Berkner Island, Antarctica: methods, dating and first results

Annals of Glaciology ◽

10.3189/172756404781814104 ◽

2004 ◽

Vol 39 ◽

pp. 146-154 ◽

Cited By ~ 12

Author(s):

Urs Ruth ◽

Dietmar Wagenbach ◽

Robert Mulvaney ◽

Hans Oerter ◽

Wolfgang Graf ◽

...

Keyword(s):

Major Ions ◽

Accumulation Rate ◽

Ice Core ◽

Regional Scale ◽

Temporal Variations ◽

Sea Salt ◽

The South ◽

Austral Spring ◽

The Core ◽

The North

AbstractA 181 m deep ice core drilled in 1994/95 on the south dome of Berkner Island, Antarctica, was analyzed for stable isotopes, major ions and microparticle concentrations. Samples for ion chromatography were prepared by using a novel technique of filling decontaminated sample from a device for continuous ice-core melting directly into the sample vials. The core was dated through identification of volcanic horizons and interpolative layer counting. The core, together with a similar core from the north dome, reveals a 1000 year history of relatively stable climate. Temporal variations in the two cores deviate from each other owing to changing patterns of regional-scale circulation; the best correspondence between them is found for MSA–. δ18O, accumulation rate and a sea-salt proxy show only negligible correlation, which suggests a complex meteorological setting. Increasing annual accumulation is observed for the last 100 years. A period of increased sea-salt concentrations started around AD 1405, as has also been observed in other cores. Microparticle concentrations are on average 1220 particles (>1.0 μm diameter) mL–1; they are enhanced from AD 1200 to 1350, possibly because of a higher atmospheric mineral dust load or because local volcanic activity was stronger than previously thought. Microparticles and NH4+ show marked but multiple and very irregular sub-annual peaks; long-term stacking of 1 year data intervals yields seasonal maxima in austral spring or mid-summer, respectively. Post-depositional redistribution was observed for MSA, NO3– and F– at volcanic horizons.

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A 40 Year Record in an Ice Core from the Dunde Ice Cap, China (Abstract)

Annals of Glaciology ◽

10.1017/s0260305500004675 ◽

1988 ◽

Vol 10 ◽

pp. 221 ◽

Cited By ~ 1

Author(s):

Wu Xiaoling ◽

Lonnie G. Thompson

Keyword(s):

Oxygen Isotope ◽

Ice Core ◽

Field Work ◽

Tibet Plateau ◽

Ice Thickness ◽

Ice Cap ◽

Pulse Radar ◽

The North ◽

Isotope Profile ◽

Isotope Content

A cooperative glacio-climatological ice-core drilling and analysis program, administered by LIGC and BPRC, has been carried out since 1984. The major objective of this study is to extract from the Dunde ice cap records of the general environmental conditions, which include drought, volcanic activity, moisture sources, glacier net balance and possibly temperature over the last 3000 years. In 1984 a group of 18 Chinese scientists and an American scientist spent 6 weeks on the Dunde ice cap. The central objective of their research was to evaluate the potential of the ice cap to yield a lengthy ice-core climate record. Results of the 1984 field work and 1985 laboratory analysis are submitted here. The Dunde ice cap (38°96′N, 96°24.5′E) is located in the north-eastern section of the Tibet plateau, China. Its length is 10.9 km; the width varies from 2.5 to 7.5 km. The total area of the ice cap is 57 km2. A 16 m core was drilled at the first site, located on a flat part of the ice cap, 5150 m a.s.l. A 10.2 m ice core was drilled at the ice cap summit (5300 m). A series of shallow cores and 2 m pits were excavated at each of the two sites and in the lower section of the ice cap. A mono-pulse radar unit was used to determine ice thickness. The ice thickness ranged between 94 and 167 m, with an average thickness of 140 m. Using a thermistor cable, minimum temperatures of −9.1° and −9.5 °C were measured in the 16 m hole and 10.2 m hole respectively. Microparticle analysis of the ice core from the Dunde ice cap revealed a very high dust content, on average 16 × 105 particles (≥0.63 to ≤16 μ in diameter) per ml of sample, i.e. 3−4 times higher than the microparticle content in the Quelccaya ice cap, Peru, and 100 times higher than in the core from Byrd Station, Antarctica. Oxygen-isotope content ranged between −12 and −14 per mil. Initially it was anticipated that the oxygen-isotope content would produce a more negative value in the Dunde ice cap. More work is required to explain the mechanism controlling δ18o variation in the ice core from the Dunde ice cap. The microparticles, oxygen-isotope content, conductivity, and tritium measurements, together with stratigraphy, temperature and density, are presented in the figures. The 40 year net-balance record reconstructed from the ice-core and oxygen-isotope profile is in good agreement with data from precipitation and major temperature trends obtained for the last 30 years from Delingha meteorological station, which is located 160 km south-east of the ice cap.

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Part I: The Ogive Banding

Journal of Glaciology ◽

10.3189/s002214300001683x ◽

1954 ◽

Vol 2 (16) ◽

pp. 423-428

Keyword(s):

The South ◽

Outlet Glacier ◽

North West ◽

South Eastern ◽

Ice Cap ◽

The North

AbstractMorsárjökull is a small outlet glacier of Vatnajökull, Iceland. Two outlet streams from the ice cap unite at the foot of a precipitous step and carry a well-developed medial moraine; the north-west glacier stream is fed by a steep ice fall, the south-eastern one has been fed only by avalanches since 1938.The movement of the glacier was measured and showed that the alternate dark and light ogives were one year’s movement apart. Their characteristics are described and tentative suggestions concerning their mode of origin are proposed.

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A reinterpretation of sea-salt records in Greenland and Antarctic ice cores?

Annals of Glaciology ◽

10.3189/172756404781814681 ◽

2004 ◽

Vol 39 ◽

pp. 276-282 ◽

Cited By ~ 16

Author(s):

Andrew M. Rankin ◽

Eric W. Wolff ◽

Robert Mulvaney

Keyword(s):

Sea Ice ◽

Ice Core ◽

Open Water ◽

Weddell Sea ◽

Sea Salt ◽

Sea Salt Aerosol ◽

Ice Surface ◽

Frost Flowers ◽

Ice Production ◽

Ice Core Records

AbstractIt has recently been shown that much sea-salt aerosol around the coast of Antarctica is generated not from open water, but from the surface of newly formed sea ice. Previous interpretations of ice-core records have disregarded the sea-ice surface as a source of sea salt. The majority of sea-salt aerosol at Halley research station originates from frost flowers rather than open water, and the seasonal cycle of sea salt in aerosol at Halley appears to be controlled by ice production in the Weddell Sea, as well as variations in wind speed. Frost flowers are also an important source of aerosol at Siple Dome, suggesting that variations in sea-salt concentrations in the core, and other cores drilled in similar locations, may be reflecting changes in sea-ice production rather than changes in transportation patterns. For Greenland cores, and those from low-accumulation inland sites in Antarctica, it is not simple to calculate the proportion of sea salt originating from frost flowers rather than open water. However, modelling studies suggest that a sea-ice surface source contributed much of the flux of sea salt to these sites in glacial periods, suggesting that interpretations of ice-core records from these locations should also be revisited.

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Aspects of the Glaciology of Meighen Island, Northwest Territories, Canada

Journal of Glaciology ◽

10.1017/s0022143000018396 ◽

1965 ◽

Vol 5 (40) ◽

pp. 399-410 ◽

Cited By ~ 17

Author(s):

K. C. Arnold

Keyword(s):

Snow Accumulation ◽

The Arctic ◽

North Coast ◽

Ice Cap ◽

The North ◽

Four Seasons ◽

Northern Half ◽

Northern Edge ◽

Summer Temperatures ◽

Made In

Abstract Meighen Island lies in the centre of the north coast of the Queen Elizabeth Islands and fronts on the Arctic Ocean. An ice cap of about 76 km.2 covers about one-tenth of the island. Its greatest thickness of 150 m. occurs under the summit, near the south end, which was 268 m. above sea-level in 1960. The northern half of the ice cap is less than 30 m. thick; and the total volume is of the order of 2,000 × 106 m.3. Precipitation is low in the northern Queen Elizabeth Islands, and Meighen Island lies in an area where summer temperatures are lowest. In the winters of 1959–60, 1960–61 and 1961–62, the snow accumulation was 12.6, 18.2 and 14.1 cm. of water equivalent. Some snowfall remained on the higher part of the ice cap in the cold summer of 1961; but the ice cap diminished in volume in each year; by 36 × 106, 72 × 106, 22 × 106 and 91 × 106 m.3 in the 1959, 1960, 1961 and 1962 ablation seasons. If the conditions of these four seasons were maintained the ice cap would disappear in about 100 yr. However, a radio-carbon dating of a saxifrage exposed by the retreat of the ice from a small nunatak near the northern edge gave a date of less than 100 yr., and it appears that the existence of the ice cap might be sensitively related to recent climatic change. Careful surveys were made in 1959, 1960 and 1961 in an attempt to detect movement in the ice cap. Unequivocal evidence is not available from these surveys; but the stake network has been maintained and another survey has recently been completed.

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Glaciological Reconnaissance of the Sukkertoppen Ice Cap, South-West Greenland

Journal of Glaciology ◽

10.1017/s0022143000028392 ◽

1963 ◽

Vol 4 (36) ◽

pp. 813-816 ◽

Cited By ~ 8

Author(s):

C. Bull

Keyword(s):

Snow Accumulation ◽

The South ◽

West Greenland ◽

Ice Cap ◽

South West ◽

Eastern Edge

AbstractGravity studies indicate that the Sukkertoppen ice cap is about 400 m. thick. The annual snow accumulation increases westwards from about 13 g. cm.−2near the eastern edge of the ice cap to about 34 g. cm.−2near Mount Atter, in the south-west. Probably all of the ice cap is “temperate”.

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Studies of Englacial Profiles in the Lake Hazen Area of Northern Ellesmere Island

Journal of Glaciology ◽

10.3189/s002214300002373x ◽

1960 ◽

Vol 3 (27) ◽

pp. 610-625

Author(s):

G. Hattersley-Smith

Keyword(s):

Crystal Structure ◽

Budget Deficit ◽

Ice Core ◽

Ellesmere Island ◽

Equilibrium Line ◽

Mean Annual Temperature ◽

The Past ◽

Ice Cap ◽

The North ◽

The Mean

AbstractGlaciological research on the ice cap to the north of Lake Hazen in northern Ellesmere Island was one of the main objectives of the Canadian I.G.Y. expedition to this area in 1957–1958. The method of nourishment of this ice cap and of Gilman Glacier, one of its southward-flowing outlets, was studied in pit and bore hole profiles above and below the equilibrium line, which was found at an elevation of about 1,200 m. Between an elevation of about 1,450 and 2,000 m. accumulation is by firn formation, while between about 1,280 and 1,450 m. interfingering of firn and superimposed ice occurs. At 1,800 m. the mean annual accumulation over the past twenty years is estimated as 12.8 g. cm.–2. On Gilman Glacier below the equilibrium line variations in density and crystal structure in an ice core to a depth of 25 m. are seen to depend on the proportion of firn to superimposed ice formed during accumulation. These variations correspond to past changes in the position of the equilibrium line. Englacial temperature measurements indicate a mean annual temperature of about –18.5° C. at an elevation of 1 ,040 m. A budget deficit for Gilman Glacier during two years of observations may be related to the increased summer melting of the last 20 years, deduced from pit studies at 1,800 m.

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