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

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±0.10 g cm-2 year-1, that is 8±4 % higher than initial (not corrected) value from the accumulation-stake measurements.</p>

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

2019 ◽  
Vol 65 (1) ◽  
pp. 46-62 ◽  
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.

Underestimation of Snow Accumulation Rate in Central Antarctica (Vostok Station) Derived from Stake Measurements

2020 ◽  
Vol 45 (2) ◽  
pp. 132-140
Author(s):  
A. A. Ekaykin ◽  
N. A. Teben’kova ◽  
V. Ya. Lipenkov ◽  
K. B. Tchikhatchev ◽  
A. N. Veres ◽  
...  
Keyword(s):  
Accumulation Rate ◽  
Snow Accumulation ◽  
Vostok Station

scholarly journals Spatial variability at shallow snow-layer depths in central Dronning Maud Land, East Antarctica

1999 ◽  
Vol 29 ◽  
pp. 10-16 ◽  
Author(s):  
Cecilia Richardson ◽  
Per Holmlund
Keyword(s):  
Spatial Variability ◽  
Accumulation Rate ◽  
Marked Change ◽  
Ice Cores ◽  
Snow Accumulation ◽  
East Antarctica ◽  
Snow Layer ◽  
Accumulation Pattern ◽  
Single Action ◽  
Dronning Maud Land

AbstractThe spatial variability in snow accumulation varies between different regions in Dronning Maud Land, East Antarctica. This pattern cannot easily be explained by the single action of parameters such as distance to open sea, surface elevation or slope. In 1996-97 we mapped snow-layer depths within the top 11 m of the snowpack with a ground-based radar along a 500 km traverse on the polar plateau in central Dronning Maud Land. The results showed that the general accumulation pattern could be described by three major characteristic sections: a pronounced trend of decreasing net accumulation with increasing altitude from 2400 to 2840 m a.s.l.; relatively high erosion rates and occurrence of areas with net erosion at 2840-3140 m a.s.l.; and a slight trend of decreasing net accumulation with increasing altitude from 3140 to 3450 m a.s.l. The spatial variability in snow-layer depths showed a marked change around 3080 m a.s.l., with high variability at lower elevations and low variability at higher elevations. We also determined the spatial representativeness of 11 firn cores drilled along the traverse. In general, the representativeness of the cores was high. However, the core with the lowest representativeness underestimated the mean accumulation rate around the coring site by 22%. This shows that snow-radar data on spatial snow distribution are important for the interpretation of accumulation rates obtained from firn and ice cores.

scholarly journals Non-climatic signal in ice core records: lessons from Antarctic megadunes

2016 ◽  
Vol 10 (3) ◽  
pp. 1217-1227 ◽  
Author(s):  
Alexey Ekaykin ◽  
Lutz Eberlein ◽  
Vladimir Lipenkov ◽  
Sergey Popov ◽  
Mirko Scheinert ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Isotopic Composition ◽  
Vertical Profile ◽  
Accumulation Rate ◽  
Climatic Variability ◽  
Ice Core ◽  
Ice Cores ◽  
Snow Accumulation ◽  
Vostok Station ◽  
Isotope Content

Abstract. We present the results of glaciological investigations in the megadune area located 30 km to the east of Vostok Station (central East Antarctica) implemented during the 58th, 59th and 60th Russian Antarctic Expedition (January 2013–2015). Snow accumulation rate and isotope content (δD, δ18O and δ17O) were measured along the 2 km profile across the megadune ridge accompanied by precise GPS altitude measurements and ground penetrating radar (GPR) survey. It is shown that the spatial variability of snow accumulation and isotope content covaries with the surface slope. The accumulation rate regularly changes by 1 order of magnitude within the distance < 1 km, with the reduced accumulation at the leeward slope of the dune and increased accumulation in the hollow between the dunes. At the same time, the accumulation rate averaged over the length of a dune wave (22 mm w.e.) corresponds well with the value obtained at Vostok Station, which suggests no additional wind-driven snow sublimation in the megadunes compared to the surrounding plateau. The snow isotopic composition is in negative correlation with the snow accumulation. Analysing dxs ∕ δD and 17O-excess ∕ δD slopes (where dxs  =  δD − 8 ⋅ δ18O and 17O-excess  =  ln(δ17O  ∕  1000 +  1) −0.528 ⋅ ln (δ18O ∕ 1000 + 1)), we conclude that the spatial variability of the snow isotopic composition in the megadune area could be explained by post-depositional snow modifications. Using the GPR data, we estimated the apparent dune drift velocity (4.6 ± 1.1 m yr−1). The full cycle of the dune drift is thus about 410 years. Since the spatial anomalies of snow accumulation and isotopic composition are supposed to drift with the dune, a core drilled in the megadune area would exhibit the non-climatic 410-year cycle of these two parameters. We simulated a vertical profile of snow isotopic composition with such a non-climatic variability, using the data on the dune size and velocity. This artificial profile is then compared with the real vertical profile of snow isotopic composition obtained from a core drilled in the megadune area. We note that the two profiles are very similar. The obtained results are discussed in terms of interpretation of data obtained from ice cores drilled beyond the megadune areas.

scholarly journals Constraints on snow accumulation and firn density in Greenland using GPS receivers

2015 ◽  
Vol 61 (225) ◽  
pp. 101-114 ◽  
Author(s):  
Kristine M. Larson ◽  
John Wahr ◽  
Peter Kuipers Munneke
Keyword(s):  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Vertical Displacement ◽  
Snow Accumulation ◽  
Vertical Position ◽  
Snow Surface ◽  
Snow Layer ◽  
Gps Antenna ◽  
Better Than

AbstractData from three continuously operating GPS sites located in the interior of the Greenland ice sheet are analyzed. Traditionally these kinds of GPS installations (where the GPS antenna is placed on a pole deployed into the firn) are used to estimate the local horizontal speed and direction of the ice sheet. However, these data are also sensitive to the vertical displacement of the pole as it moves through the firn layer. A new method developed to measure snow depth variations with reflected GPS signals is applied to these GPS data from Greenland. This method provides a constraint on the vertical distance between the GPS antenna and the surface snow layer. The vertical positions and snow surface heights are then used to assess output from surface accumulation and firn densification models, showing agreement better than 10% at the sites with the longest records. Comparisons between the GPS reflection method and in situ snow sensors at the Dye-2 site show good agreement, capturing the dramatic changes observed in Greenland during the 2012 summer melt season. The geocentric elevation of the snow surface can be inferred by subtracting the snow surface height estimates from the vertical position measurements. It should be possible to use those surface elevation estimates to help validate elevation results obtained from satellite altimetry.

scholarly journals Mechanical Instability of Snowcover with Saturated Layer

1985 ◽  
Vol 6 ◽  
pp. 292-294
Author(s):  
Yasuaki Nohguchi
Keyword(s):  
Elastic Deformation ◽  
Field Observations ◽  
Lateral Movement ◽  
Snow Surface ◽  
Mechanical Instability ◽  
Snow Density ◽  
Snow Layer ◽  
Saturated Layer ◽  
Water Saturated

If rain falls on a new snowcover, a water saturated layer is often clearly formed in it. A snowcover with a saturated layer is sometimes unstable; the snowcover is folded and dimples appear on the snow surface. The mechanism of this instability is discussed theoretically. As a result, we find that a snowcover with a saturated layer can be unstable owing to lateral movement of water along a saturated layer and elastic deformation of the snow layer directly under it. Then the wavelength of the instability depends on the snow density; this result is consistent with field observations.

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

2004 ◽  
Vol 39 ◽  
pp. 569-575 ◽  
Author(s):  
Alexei A. Ekaykin ◽  
Vladimir Ya. Lipenkov ◽  
Irina N. Kuzmina ◽  
Jean Robert Petit ◽  
Valérie MASSON-Delmotte ◽  
...  
Keyword(s):  
Isotope Composition ◽  
Accumulation Rate ◽  
Surface Air Temperature ◽  
Snow Accumulation ◽  
General Tendency ◽  
Near Surface ◽  
The Past ◽  
The Pacific ◽  
Isotope Record ◽  
Vostok Station

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.

scholarly journals High-resolution 900 year volcanic and climatic record from the Vostok area, East Antarctica

2014 ◽  
Vol 8 (3) ◽  
pp. 843-851 ◽  
Author(s):  
E. Y. Osipov ◽  
T. V. Khodzher ◽  
L. P. Golobokova ◽  
N. A. Onischuk ◽  
V. Y. Lipenkov ◽  
...  
Keyword(s):  
Atmospheric Transport ◽  
Accumulation Rate ◽  
Ice Cores ◽  
Snow Accumulation ◽  
East Antarctica ◽  
Low Latitude ◽  
Atmospheric Circulation Patterns ◽  
Circulation Patterns ◽  
Vostok Station ◽  
Climatic Record

Abstract. Ion chromatography measurements of 1730 snow and firn samples obtained from three short cores and one pit in the Vostok station area, East Antarctica, allowed for the production of the combined volcanic record of the last 900 years (AD 1093–2010). The resolution of the record is 2–3 samples per accumulation year. In total, 24 volcanic events have been identified, including seven well-known low-latitude eruptions (Pinatubo 1991, Agung 1963, Krakatoa 1883, Tambora 1815, Huanaputina 1600, Kuwae 1452, El Chichon 1259) found in most of the polar ice cores. In comparison with three other East Antarctic volcanic records (South Pole, Plateau Remote and Dome C), the Vostok record contains more events within the last 900 years. The differences between the records may be explained by local glaciological conditions, volcanic detection methodology, and, probably, differences in atmospheric circulation patterns. The strongest volcanic signal (both in sulfate concentration and flux) was attributed to the AD 1452 Kuwae eruption, similar to the Plateau Remote and Talos Dome records. The average snow accumulation rate calculated between volcanic stratigraphic horizons for the period AD 1260–2010 is 20.9 mm H2O. Positive (+13%) anomalies of snow accumulation were found for AD 1661–1815 and AD 1992–2010, and negative (−12%) for AD 1260–1601. We hypothesized that the changes in snow accumulation are associated with regional peculiarities in atmospheric transport.

scholarly journals Mechanical Instability of Snowcover with Saturated Layer

1985 ◽  
Vol 6 ◽  
pp. 292-294 ◽  
Author(s):  
Yasuaki Nohguchi
Keyword(s):  
Elastic Deformation ◽  
Field Observations ◽  
Lateral Movement ◽  
Snow Surface ◽  
Mechanical Instability ◽  
Snow Density ◽  
Snow Layer ◽  
Saturated Layer ◽  
Water Saturated

If rain falls on a new snowcover, a water saturated layer is often clearly formed in it. A snowcover with a saturated layer is sometimes unstable; the snowcover is folded and dimples appear on the snow surface. The mechanism of this instability is discussed theoretically. As a result, we find that a snowcover with a saturated layer can be unstable owing to lateral movement of water along a saturated layer and elastic deformation of the snow layer directly under it. Then the wavelength of the instability depends on the snow density; this result is consistent with field observations.

scholarly journals Non-climatic signal in ice core records: lessons from Antarctic mega-dunes

2015 ◽  
Vol 9 (6) ◽  
pp. 6909-6936
Author(s):  
A. Ekaykin ◽  
L. Eberlein ◽  
V. Lipenkov ◽  
S. Popov ◽  
M. Scheinert ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Isotopic Composition ◽  
Vertical Profile ◽  
Accumulation Rate ◽  
Ice Core ◽  
Ice Cores ◽  
Snow Accumulation ◽  
Vostok Station ◽  
Isotope Content ◽  
Dune Area

Abstract. We present the results of glaciological investigations in the mega-dune area located 30 km to the east from Vostok Station (central East Antarctica) implemented during the 58th, 59th and 60th Russian Antarctic Expedition (January 2013–January 2015). Snow accumulation rate and isotope content (δD, δ18O and δ17O) were measured along the 2 km profile across the mega-dune ridge accompanied by precise GPS altitude measurements and GPR survey. It is shown that the spatial variability of snow accumulation and isotope content covaries with the surface slope. The accumulation rate regularly changes by one order of magnitude within the distance < 1 km, with the reduced accumulation at the leeward slope of the dune and increased accumulation in the hollow between the dunes. At the same time, the accumulation rate averaged over the length of a dune wave (22 mm we) corresponds well with the value obtained at Vostok Station, which suggests no additional wind-driven snow sublimation in the mega-dunes compared to the surrounding plateau. The snow isotopic composition is in negative correlation with the snow accumulation. Analyzing dxs/δD and 17O-excess/δD slopes, we conclude that the spatial variability of the snow isotopic composition in the mega-dune area could be explained by post-depositional snow modifications. Using the GPR data, we estimated the apparent dune drift velocity (4.6 ± 1.1 m yr−1). The full cycle of the dune drift is thus about 410 years. Since the spatial anomalies of snow accumulation and isotopic composition are supposed to drift with the dune, an ice core drilled in the mega-dune area would exhibit the non-climatic 410 year cycle of these two parameters. We simulated a vertical profile of snow isotopic composition with such a non-climatic variability, using the data on the dune size and velocity. This artificial profile is then compared with the real vertical profile of snow isotopic composition obtained from a core drilled in the mega-dune area. We note that the two profiles are very similar. The obtained results are discussed in terms of interpretation of data obtained from ice cores drilled beyond the mega-dune areas.

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