The changes in isotope composition and accumulation of snow at Vostok station, East Antarctica, over the past 200 years

AbstractHigh-resolution records of isotope composition (δD) and accumulation of snow have been obtained from 10–12m deep snow pits dug in the vicinity of Vostok station during the 1979/80 and 1999/2000 Antarctic field seasons. We employ meteorological, balloon-sounding and snow-stake data to interpret the isotope record in terms of past temperature changes. Our reconstruction suggests that snow accumulation rate and the near-surface air temperature at Vostok have varied during the past 200 years between 15 and 30 kg m–2 a–1, and between –56 and –55˚C, respectively, with a slight general tendency to increase from the past to the present. Both parameters reveal a 50 year periodicity that correlates with the Pacific Decadal Oscillation index, implying a climatic teleconnection between central Antarctica and the tropical Pacific.

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Spatial and temporal variability in isotope composition of recent snow in the vicinity of Vostok station, Antarctica: implications for ice-core record interpretation

Annals of Glaciology ◽

10.3189/172756402781816726 ◽

2002 ◽

Vol 35 ◽

pp. 181-186 ◽

Cited By ~ 74

Author(s):

Alexey A. Ekaykin ◽

Vladimir Ya. Lipenkov ◽

Narcisse I. Barkov ◽

Jean Robert Petit ◽

Valerie Masson-Delmotte

Keyword(s):

Isotope Composition ◽

Ice Core ◽

Snow Accumulation ◽

Spatial And Temporal Variability ◽

Weak Correlation ◽

Ice Core Record ◽

Vostok Station ◽

The Mean ◽

Mean Annual Air Temperature ◽

Snow Samples

AbstractContinuous, detailed isotope (δD and δ18O) 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, ~102 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.

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Systematic underestimation of snow accumulation rate by stake measurements in central Antarctica

10.5194/egusphere-egu2020-9891 ◽

2020 ◽

Author(s):

Alexey Ekaykin ◽

Natalia Tebenkova ◽

Vladimir Lipenkov ◽

Arina Veres ◽

Kirill Tchikhatchev ◽

...

Keyword(s):

Density Profile ◽

Accumulation Rate ◽

Snow Accumulation ◽

Geodetic Data ◽

Reliable Estimate ◽

Snow Surface ◽

Snow Density ◽

Snow Layer ◽

Vostok Station

<p>We demonstrate that the accumulation-stake measurements in central Antarctica systematically underestimate the value of the snow build-up due to the compaction of snow layer between the stake base and the snow surface. We have developed two methods to define the corresponding correction to the snow build-up measurements at the stake farm near Vostok station. The first method is based on "Sorge's law" to calculate the rate of thinning of the snow layers using the vertical snow density profile. The second method consists of direct instrumental measurements of this thinning in the field. We have also involved the data of other two independent methods to estimate the snow accumulation rate in the vicinity of Vostok - first, geodetic data on the rate of snow layer sinking and, second, glaciological data from snow pits. The most reliable estimate of the snow accumulation rate in this region is 2.26&#177;0.10 g cm-2 year-1, that is 8&#177;4 % higher than initial (not corrected) value from the accumulation-stake measurements.</p>

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New insights into the climatic signal from firn cores at the northern Antarctic Peninsula

10.5194/tc-2016-298 ◽

2017 ◽

Author(s):

Francisco Fernandoy ◽

Dieter Tetzner ◽

Hanno Meyer ◽

Guisella Gacitúa ◽

Kirstin Hoffmann ◽

...

Keyword(s):

Sea Ice ◽

Antarctic Peninsula ◽

Isotope Composition ◽

Accumulation Rate ◽

Regional Scale ◽

Inversion Layer ◽

Lower Troposphere ◽

High Temporal Resolution ◽

Near Surface ◽

The Antarctic

Abstract. The Antarctic Peninsula is one of the most challenging regions of Antarctica from a climatological perspective, owing to the recent atmospheric and oceanic warming. The steep topography and a lack of long–term and in situ meteorological observations complicate extrapolation of existing climate models to the sub-regional scale. Here, we present new evidence from the northern Antarctic Peninsula to demonstrate how stable water isotopes of firn cores and recent precipitation samples can reveal climatic processes related to nearby oceanic and atmospheric conditions. A noticeable effect of the sea ice cover on local temperatures and atmospheric modes, in particular the Southern Annular Mode (SAM), is demonstrated. In years with large sea ice extension in winter (negative SAM anomaly), an inversion layer in the lower troposphere develops at the coastal zone. Therefore, an isotope–temperature relationship valid for all seasons cannot be concluded. The δ–T relationship rather depends on seasonal variability of oceanic conditions. Transitional seasons (autumn and spring) are both stable seasons with an isotope–temperature gradient of +0.69 ‰ °C−1. The firn stable isotope composition reveals that the near–surface temperature at the Antarctic Peninsula shows a decreasing trend (−0.33 °C y−1) between 2008 and 2014. Moreover, the deuterium excess (dexcess) has been demonstrated to be a reliable indicator of seasonal oceanic conditions, and therefore suitable to improve a firn age model based on seasonal dexcess variability. The annual accumulation rate in this region is highly variable, ranging between 1060 kg m−2 y−1 and 2470 kg m−2 y−1 from 2008 to 2014. The combination of isotopic and meteorological data is key for reconstructing recent climatic conditions with a high temporal resolution in polar regions where no direct observation exists

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Snow-accumulation rates and isotopic content (2H,3H) of near-surface firn from the Filchner-Ronne Ice Shelf, Antarctica

Annals of Glaciology ◽

10.1017/s0260305500016335 ◽

1994 ◽

Vol 20 ◽

pp. 121-128 ◽

Cited By ~ 1

Author(s):

W. Graf ◽

H. Moser ◽

O. Reinwarth ◽

J. Kipfstuhl ◽

H. Oerter ◽

...

Keyword(s):

Accumulation Rate ◽

Ice Cores ◽

Snow Accumulation ◽

Accumulation Rates ◽

Ice Shelf ◽

Near Surface ◽

Surface Data ◽

Chemical Profiles ◽

Ice Edge ◽

The Antarctic

The accumulation and distribution of the2H content of near-surface layers in the eastern part of the Ronne Ice Shelf were determined from 16 firn cores drilled to about 10 m depth during the Filchner IIIa and IV campaigns in 1990 and 1992, respectively. The cores were dated stratigraphically by seasonal δ2H variations in the firn. In addition,3H and high-resolution chemical profiles were used to assist in dating. Both the accumulation rate and the stable-isotope content decrease with increasing distance from the ice edge: the δ2H values range from about 195‰ at the ice edge to -25‰ at BAS sites 5 and 6, south of Henry Ice Rise, and the accumulation rates from about 210 to 90 kgm-2a-1. The δ2H values of the near-surface firn and the 10 m firn temperatures (Θ) at individual sites are very well correlated: dδ2H/dΘ = (10.3 ± 0.6)‰K-1; r = 0.97.The δ2H profiles of the two ice cores BI3 and BI5 drilled in 1990 and 1992 to 215 and 320 m depth, respectively, reflect the gradual depletion in2H in the firn upstream of the drill sites. Comparison with the surface data indicates that the ice above 142 m in core BIS and above 137 m in core BI3 was deposited on the ice shelf, whereas the deeper ice, down to 152.8 m depth, most probably originated from the margin of the Antarctic ice sheet.

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Spatial variability of snow isotopic composition and accumulation rate at the stake farm of Vostok station (Сentral Antarctica)

Arctic and Antarctic Research ◽

10.30758/0555-2648-2019-65-1-46-62 ◽

2019 ◽

Vol 65 (1) ◽

pp. 46-62 ◽

Cited By ~ 1

Author(s):

A. A. Ekaykin ◽

D. O. Vladimirova ◽

N. A. Tebenkova ◽

E. V. Brovkov ◽

A. N. Veres ◽

...

Keyword(s):

Spatial Distribution ◽

Spatial Variability ◽

Isotopic Composition ◽

Accumulation Rate ◽

Ice Sheet ◽

Ice Cores ◽

Snow Accumulation ◽

Geochemical Data ◽

Snow Surface ◽

Vostok Station

The knowledge of the spatial distribution of the snow accumulation rate and isotopic composition in different scales, from local to continental, over the Antarctic Ice Sheet is critically important for the interpretation of the paleoclimate data obtained from deep ice cores, for correct assessment of the ice sheet mass balance, etc. With this in mind, we have synthesized geodetic, glaciological and geochemical data collected in the vicinity of central Antarctic Vostok station in 1970–2017 in order to shed light on the processes governing the spatial distribution of snow isotopic composition and accumulation rate in the spatial scale from 100 to 1000 m. First, we have discovered that snow surface height and snow accumulation rate field are strongly affected by the influence of the logistic convoy route annually operating between Russian Antarctic stations Vostok and Progress. This influence is detectable up to 1 km leeward from the route. At the same time the isotopic composition of the upper 10 cm of the snow does not show any anomalies in the vicinity of the route. This is an unexpected result, because large anomalies of the ice sheet surface (e.g., megadunes) are known to affect the snow isotopic composition. Second, in the undisturbed part of the snow surface near Vostok station we have discovered quasi-periodic (with the wavelength of about 400 m) low-amplitude variations of the surface height that are covariant with the corresponding waves in snow accumulation and isotopic composition. We suggest that spatial variability of the snow isotopic composition is due to the different ratio of summer and winter precipitation deposited in different locations, as evident from a strong negative correlation between δD and dxs parameters. The results of this study may explain the nature of the low-frequency noise (with the time-scale from decades to centuries) observed in the climate records obtained from shallow and deep ice cores in central Antarctica.

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The Internal Multidecadal Variability of SST in the Pacific and Its Impact on Air Temperature and Rainfall over Land in the Northern Hemisphere

Atmosphere ◽

10.3390/atmos10030153 ◽

2019 ◽

Vol 10 (3) ◽

pp. 153

Author(s):

Hua Chen ◽

Donglin He ◽

Zhiwei Zhu

Keyword(s):

Northern Hemisphere ◽

Air Temperature ◽

Critical Role ◽

Surface Air Temperature ◽

Ensemble Empirical Mode Decomposition ◽

Near Surface ◽

Multidecadal Variability ◽

The North ◽

Mode Decomposition ◽

The Pacific

Based on the centennial-scale observations and re-analyses, this paper employs the ensemble empirical mode decomposition to separate the internal multidecadal variability (IMV) from the externally-forced variability of sea surface temperature (SST), and then defines new indices that represent the IMV of SST in the North Pacific (NPIMV) and South Pacific (SPIMV), respectively. The spatial structure of NPIMV/SPIMV shows remarkably positive SST anomaly only in the index-defined region; meanwhile, the temporal evolutions of NPIMV and SPIMV are uncorrelated, indicating their independence of each other. Both NPIMV and SPIMV play a critical role in the near-surface air temperature and rainfall over land in the Northern hemisphere, especially in the season when their intensity is the strongest. It is through teleconnection wave trains that NPIMV and SPIMV exert influences on remote regions. Results from another two rainfall datasets are found to be consistent in the majority of the Northern hemisphere in response to NPIMV/SPIMV, yet disagreement exists in certain regions due to large uncertainties of rainfall datasets.

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Dominant role of vertical air flows in the unprecedented warming on the Antarctic Peninsula in February 2020

Communications Earth & Environment ◽

10.1038/s43247-021-00203-w ◽

2021 ◽

Vol 2 (1) ◽

Author(s):

Min Xu ◽

Lejiang Yu ◽

Kaixin Liang ◽

Timo Vihma ◽

Deniz Bozkurt ◽

...

Keyword(s):

Pacific Ocean ◽

Antarctic Peninsula ◽

Dominant Role ◽

Austral Summer ◽

Surface Air Temperature ◽

Near Surface ◽

The Pacific ◽

The Pacific Ocean ◽

Air Flows ◽

The Antarctic

AbstractNear-surface air temperature at the Argentinian research base Esperanza on the northern tip of the Antarctic Peninsula reached 18.3 °C on 6 February 2020, which is the highest temperature ever recorded on the entire Antarctic continent. Here we use weather observations since 1973 together with the ERA5 reanalysis to investigate the circulation that shaped the 2020 event, and its context over the past decades. We find that, during the 2020 event, a high-pressure ridge over the 40°-100°W sector and a blocking high on the Drake Passage led to an anticyclonic circulation that brought warm and moist air from the Pacific Ocean to the Antarctic Peninsula. Vertical air flows in a foehn warming event dominated by sensible heat and radiation made the largest contribution to the abrupt warming. A further analysis with 196 extreme warm events in austral summer between 1973 and 2020 suggests that the mechanisms behind the 2020 event form one of the two most common clusters of the events, exhibiting that most of the extreme warm events at Esperanza station are linked to air masses originating over the Pacific Ocean.

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Ice-nucleating particle concentrations of the past: insights from a 600-year-old Greenland ice core

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-12459-2020 ◽

2020 ◽

Vol 20 (21) ◽

pp. 12459-12482 ◽

Cited By ~ 1

Author(s):

Jann Schrod ◽

Dominik Kleinhenz ◽

Maria Hörhold ◽

Tobias Erhardt ◽

Sarah Richter ◽

...

Keyword(s):

Accumulation Rate ◽

Deposition Velocity ◽

Ice Core ◽

Flow Analysis ◽

Correlation Coefficients ◽

Sem Analysis ◽

Snow Accumulation ◽

Radiative Properties ◽

The Past ◽

Special Events

Abstract. Ice-nucleating particles (INPs) affect the microphysics in cloud and precipitation processes. Hence, they modulate the radiative properties of clouds. However, atmospheric INP concentrations of the past are basically unknown. Here, we present INP measurements from an ice core in Greenland, which dates back to the year 1370. In total 135 samples were analyzed with the FRIDGE droplet freezing assay in the temperature range from −14 to −35 ∘C. The sampling frequency was set to 1 in 10 years from 1370 to 1960. From 1960 to 1990 the frequency was increased to one sample per year. Additionally, a few special events were probed, including volcanic episodes. The typical time coverage of a sample was on the order of a few months. Historical atmospheric INP concentrations were estimated with a conversion factor, which depends on the snow accumulation rate of the ice core, particle dry deposition velocity, and wet scavenging ratio. Typical atmospheric INP concentrations were on the order of 0.1 L−1 at −25 ∘C. The INP variability was found to be about 1–2 orders of magnitude. Yet, the short-term variability from samples over a seasonal cycle was considerably lower. INP concentrations were significantly correlated to some chemical tracers derived from continuous-flow analysis (CFA) and ion chromatography (IC) over a broad range of nucleation temperatures. The highest correlation coefficients were found for the particle concentration (spherical diameter dp > 1.2 µm). The correlation is higher for a time period of seasonal samples, where INP concentrations follow a clear annual pattern, highlighting the importance of the annual dust input in Greenland from East Asian deserts during spring. Scanning electron microscopy (SEM) analysis of selected samples found mineral dust to be the dominant particle fraction, verifying their significance as INPs. Overall, the concentrations compare reasonably well to present-day INP concentrations, albeit they are on the lower side. However, we found that the INP concentration at medium supercooled temperatures differed before and after 1960. Average INP concentrations at −23, −24, −25, −26, and −28 ∘C were significantly higher (and more variable) in the modern-day period, which could indicate a potential anthropogenic impact, e.g., from land-use change.

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Air Temperature and Snow Accumulation in the Antarctic Peninsula During the Past 50 Years (Abstract)

Annals of Glaciology ◽

10.3189/s0260305500006674 ◽

1988 ◽

Vol 11 ◽

pp. 207-207 ◽

Cited By ~ 2

Author(s):

David A. Peel ◽

Robert Mulvaney

Keyword(s):

Antarctic Peninsula ◽

Accumulation Rate ◽

Ice Sheet ◽

Ice Cores ◽

Snow Accumulation ◽

The West ◽

Climate Type ◽

The Past ◽

The Antarctic ◽

Noise Factors

Trends in climate affecting the West Antarctic ice sheet may be detected first in the Antarctic Peninsula region. Although the area contains the most comprehensive weather records for any part of Antarctica, reliable snow-accumulation data are lacking.Mainly as a result of the large snow-accumulation rate in the region (typically in the range 4.0–10.0 kg m−2 a−1), stratigraphie evidence of climate derived from ice cores can be resolved in much greater detail than is possible over most of the continent. Ice cores have been drilled at two sites, representing the extremes of climate type encountered in the region. A 133 m core has been obtained from Dolleman Island (70°35.2′S, 60°55.5′W) to represent the continental-type climate of the Weddell coast region, and an 87 m core has been obtained from the Palmer Land plateau (74°01′S, 70°38′W) to represent the more maritime regime of the west coast and central areas. Replicated cores were obtained at both sites in order to assess the contribution of local noise factors to the climatic signal preserved in the cores. Climatic trends during the period 1938–86 have been assessed on the basis of stable-isotope analysis of the top 47 m of the Palmer Land core and of the top 32 m of the Dolleman Island core.A statistical analysis of derived profiles of mean annual δ18O and accumulation rate indicates that the local noise factors at these sites are sufficiently small that data averaged over periods as short as 5 years should reveal climatic shifts at the level of 0.2% and 5% respectively. These changes are much smaller than trends that have actually occurred during the past 50 years.The most notable trend over the past 30 years is an increase of more than 30% in the snow-accumulation rate that has occurred in parallel with an overall temperature increase of 0.06°C/a during the same period. Increases of similar magnitude can be inferred from studies in East Antarctica, and may be related to a significant increase in precipitation rate that has been documented recently at mid-to high-latitude stations in the Northern Hemisphere. The finding may have relevance to studies of the possible consequences of a CO2-induced climate change. More extensive accumulation time series are now required from Antarctica, if satisfactory models of the long-term balance of the ice sheet are to be derived.

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Temperature history and accumulation timing for the snowpack at GISP2, central Greenland

Journal of Glaciology ◽

10.1017/s0022143000002318 ◽

1998 ◽

Vol 44 (146) ◽

pp. 21-30 ◽

Cited By ~ 13

Author(s):

C. A. Shuman ◽

R. B. Alley ◽

M. A. Fahnestock ◽

R. A. Bindschadler ◽

J. W. C. White ◽

...

Keyword(s):

High Resolution ◽

Stable Isotope ◽

Annual Variation ◽

Close Association ◽

Snow Accumulation ◽

Temperature History ◽

Near Surface ◽

Brightness Temperatures ◽

Isotope Record ◽

Temperature Proxy

AbstractPrevious research has documented a close association between high-resolution snow-pit profiles of hydrogen and oxygen stable-isotope ratios and multi-year Special Sensor Microwave/lmager (SSM/I) 37 GHz brightness temperature data in central Greenland. Comparison of the SSM/I data to profiles obtained during the 1989-91 field seasons indicated thatδD andδ18O data from the near-surface snow at the Greenland summit are a reliable, high-resolution temperature proxy. To test this new technique further, additional stable-isotope data were obtained from a 2 m snow pit constructed during late-June 1995 near the GISP2 site.This new profile, supported by pit stratigraphy and chemistry data, confirms the utility of comparing stable-isotope records with SSM/I brightness temperatures. The sub-annual variation of theδDrecord at the GISP2 site was determined using 15 match points, from approximately December 1991 through June 1995 and was guided in part by time-constrained hoar layers. The close association of these temperature proxies supports the assertion that snow accumulation occurs frequently through the year and that the isotope record initially contains temperature information from many times of the year. This is also independently confirmed by analysis of H2O2data. The slope of the multi-yearTvsδcorrelation was evaluated along with the sub-annual variation in the amount, rate and timing of accumulation. These new results are consistent with those from the previous study and they also demonstrate that the snow in this area initially contains temperature and chemical records with sub-annual resolution. This encourages confident interpretation of the paleoclimatic signal variations in the GISP2 and GRIP deep cores.

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