First glaciological investigations at Ridge B, central East Antarctica

2021 ◽  
pp. 1-10
Author(s):  
Alexey A. Ekaykin ◽  
Alexey V. Bolshunov ◽  
Vladimir Ya. Lipenkov ◽  
Mirko Scheinert ◽  
Lutz Eberlein ◽  
...  
Keyword(s):  
East Antarctica ◽  
Snow Density ◽  
Deep Drilling ◽  
Surface Mass ◽  
Annual Variations ◽  
First Results ◽  
Vostok Station ◽  
Water Stable Isotope ◽  
Isotope Content ◽  
Firn Core

Abstract The region of Ridge B in central East Antarctica is one of the last unexplored parts of the continent and, at the same time, ranks among the most promising places to search for Earth's oldest ice. In January 2020, we carried out the first scientific traverse from Russia's Vostok Station to the topographical dome of Ridge B (Dome B, 3807 m above sea level, 79.02°S, 93.69°E). The glaciological programme included continuous snow-radar profiling and geodetic positioning along the traverse's route, installation of snow stakes, measurements of snow density, collection of samples for stable water isotope and chemical analyses and drilling of a 20 m firn core. The first results of the traverse show that the surface mass balance at Dome B (2.28 g cm−2 year−1) is among the lowest in Antarctica. The firn temperature below the layer of annual variations is −58.1 ± 0.2°C. A very low value of heavy water stable isotope content (-58.2‰ for oxygen-18) was discovered at a distance of 170 km from Vostok Station. This work is the first step towards a comprehensive reconnaissance study of the Ridge B area aimed at locating the best site for future deep drilling for the oldest Antarctic ice.

scholarly journals Climate dependent contrast in surface mass balance in East Antarctica over the past 216 ka

2016 ◽  
Vol 62 (236) ◽  
pp. 1037-1048 ◽  
Author(s):  
F. PARRENIN ◽  
S. FUJITA ◽  
A. ABE-OUCHI ◽  
K. KAWAMURA ◽  
V. MASSON-DELMOTTE ◽  
...  
Keyword(s):  
Mass Balance ◽  
Ice Core ◽  
Ice Cores ◽  
East Antarctica ◽  
Surface Mass Balance ◽  
Last Interglacial ◽  
Surface Mass ◽  
The Past ◽  
Water Stable Isotope ◽  
Global Mean Sea Level

ABSTRACTDocumenting past changes in the East Antarctic surface mass balance is important to improve ice core chronologies and to constrain the ice-sheet contribution to global mean sea-level change. Here we reconstruct past changes in the ratio of surface mass balance (SMB ratio) between the EPICA Dome C (EDC) and Dome Fuji (DF) East Antarctica ice core sites, based on a precise volcanic synchronization of the two ice cores and on corrections for the vertical thinning of layers. During the past 216 000 a, this SMB ratio, denoted SMBEDC/SMBDF, varied between 0.7 and 1.1, being small during cold periods and large during warm periods. Our results therefore reveal larger amplitudes of changes in SMB at EDC compared with DF, consistent with previous results showing larger amplitudes of changes in water stable isotopes and estimated surface temperature at EDC compared with DF. Within the last glacial inception (Marine Isotope Stages, MIS-5c and MIS-5d), the SMB ratio deviates by up to 0.2 from what is expected based on differences in water stable isotope records. Moreover, the SMB ratio is constant throughout the late parts of the current and last interglacial periods, despite contrasting isotopic trends.

scholarly journals Reconstruction of historical surface mass balance, 1984–2017 from GreenTrACS multi-offset ground-penetrating radar

2020 ◽  
pp. 1-10
Author(s):  
Tate G. Meehan ◽  
H. P. Marshall ◽  
John H. Bradford ◽  
Robert L. Hawley ◽  
Thomas B. Overly ◽  
...  
Keyword(s):  
Mass Balance ◽  
Ground Penetrating Radar ◽  
Greenland Ice Sheet ◽  
Snow Accumulation ◽  
Surface Mass Balance ◽  
Snow Density ◽  
Surface Mass ◽  
Age Model ◽  
Ground Penetrating ◽  
Good Agreement

Abstract We present continuous estimates of snow and firn density, layer depth and accumulation from a multi-channel, multi-offset, ground-penetrating radar traverse. Our method uses the electromagnetic velocity, estimated from waveform travel-times measured at common-midpoints between sources and receivers. Previously, common-midpoint radar experiments on ice sheets have been limited to point observations. We completed radar velocity analysis in the upper ~2 m to estimate the surface and average snow density of the Greenland Ice Sheet. We parameterized the Herron and Langway (1980) firn density and age model using the radar-derived snow density, radar-derived surface mass balance (2015–2017) and reanalysis-derived temperature data. We applied structure-oriented filtering to the radar image along constant age horizons and increased the depth at which horizons could be reliably interpreted. We reconstructed the historical instantaneous surface mass balance, which we averaged into annual and multidecadal products along a 78 km traverse for the period 1984–2017. We found good agreement between our physically constrained parameterization and a firn core collected from the dry snow accumulation zone, and gained insights into the spatial correlation of surface snow density.

scholarly journals Stable-isotope time series and precipitation origin from firn-core and snow samples, Altai glaciers, Siberia

2005 ◽  
Vol 51 (175) ◽  
pp. 637-654 ◽  
Author(s):  
Vladimir B. Aizen ◽  
Elena Aizen ◽  
Koji Fujita ◽  
Stanislav A. Nikitin ◽  
Karl J. Kreutz ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Clustering Analysis ◽  
Meteoric Water ◽  
Drainage Basin ◽  
The Arctic ◽  
Deuterium Excess ◽  
Closed Drainage ◽  
Water Stable Isotope ◽  
Firn Core ◽  
Snow Samples

AbstractIn the summers of 2001 and 2002, glacio-climatological research was performed at 4110–4120 m a.s.l. on the Belukha snow/firn plateau, Siberian Altai. Hundreds of samples from snow pits and a 21 m snow/firn core were collected to establish the annual/seasonal/monthly depth–accumulation scale, based on stable-isotope records, stratigraphic analyses and meteorological and synoptic data. The fluctuations of water stable-isotope records show well-preserved seasonal variations. The δ18O and δD relationships in precipitation, snow pits and the snow/firn core have the same slope to the covariance as that of the global meteoric water line. The origins of precipitation nourishing the Belukha plateau were determined based on clustering analysis of δ18O and d-excess records and examination of synoptic atmospheric patterns. Calibration and validation of the developed clusters occurred at event and monthly timescales with about 15% uncertainty. Two distinct moisture sources were shown: oceanic sources with d-excess <12‰, and the Aral–Caspian closed drainage basin sources with d-excess >12‰. Two-thirds of the annual accumulation was from oceanic precipitation, of which more than half had isotopic ratios corresponding to moisture evaporated over the Atlantic Ocean. Precipitation from the Arctic/Pacific Ocean had the lowest deuterium excess, contributing one-tenth to annual accumulation.

scholarly journals Surface mass balance and water stable isotopes derived from firn cores on three ice rises, Fimbul Ice Shelf, Antarctica

2016 ◽  
Vol 10 (6) ◽  
pp. 2763-2777 ◽  
Author(s):  
Carmen P. Vega ◽  
Elisabeth Schlosser ◽  
Dmitry V. Divine ◽  
Jack Kohler ◽  
Tõnu Martma ◽  
...  
Keyword(s):  
High Resolution ◽  
Stable Isotope ◽  
Mass Balance ◽  
Temporal Variability ◽  
Ice Cores ◽  
Surface Mass Balance ◽  
Ice Shelf ◽  
Climate Signal ◽  
Surface Mass ◽  
Water Stable Isotope

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.

scholarly journals Challenges associated with the climatic interpretation of water stable isotope records from a highly resolved firn core from Adélie Land, coastal Antarctica

2019 ◽  
Vol 13 (4) ◽  
pp. 1297-1324 ◽  
Author(s):  
Sentia Goursaud ◽  
Valérie Masson-Delmotte ◽  
Vincent Favier ◽  
Suzanne Preunkert ◽  
Michel Legrand ◽  
...  
Keyword(s):  
Deuterium Excess ◽  
Austral Spring ◽  
High Accumulation ◽  
Sea Ice Extent ◽  
Air Masses ◽  
Terre Adélie ◽  
Water Stable Isotope ◽  
Process Studies ◽  
Autumn And Winter ◽  
Firn Core

Abstract. A new 21.3 m firn core was drilled in 2015 at a coastal Antarctic high-accumulation site in Adélie Land (66.78∘ S; 139.56∘ E, 602 m a.s.l.), named Terre Adélie 192A (TA192A). The mean isotopic values (-19.3‰±3.1 ‰ for δ18O and 5.4 ‰±2.2 ‰ for deuterium excess) are consistent with other coastal Antarctic values. No significant isotope–temperature relationship can be evidenced at any timescale. This rules out a simple interpretation in terms of local temperature. An observed asymmetry in the δ18O seasonal cycle may be explained by the precipitation of air masses coming from the eastern and western sectors in autumn and winter, recorded in the d-excess signal showing outstanding values in austral spring versus autumn. Significant positive trends are observed in the annual d-excess record and local sea ice extent (135–145∘ E) over the period 1998–2014. However, process studies focusing on resulting isotopic compositions and particularly the deuterium excess–δ18O relationship, evidenced as a potential fingerprint of moisture origins, as well as the collection of more isotopic measurements in Adélie Land are needed for an accurate interpretation of our signals.

scholarly journals Blowing snow detection from ground-based ceilometers: application to East Antarctica

2017 ◽  
Vol 11 (6) ◽  
pp. 2755-2772 ◽  
Author(s):  
Alexandra Gossart ◽  
Niels Souverijns ◽  
Irina V. Gorodetskaya ◽  
Stef Lhermitte ◽  
Jan T. M. Lenaerts ◽  
...  
Keyword(s):  
Wind Speed ◽  
Numerical Models ◽  
East Antarctica ◽  
Added Value ◽  
Polar Regions ◽  
Blowing Snow ◽  
Surface Mass ◽  
Direct Observations ◽  
Synoptic Conditions ◽  
Fresh Snow

Abstract. Blowing snow impacts Antarctic ice sheet surface mass balance by snow redistribution and sublimation. However, numerical models poorly represent blowing snow processes, while direct observations are limited in space and time. Satellite retrieval of blowing snow is hindered by clouds and only the strongest events are considered. Here, we develop a blowing snow detection (BSD) algorithm for ground-based remote-sensing ceilometers in polar regions and apply it to ceilometers at Neumayer III and Princess Elisabeth (PE) stations, East Antarctica. The algorithm is able to detect (heavy) blowing snow layers reaching 30 m height. Results show that 78 % of the detected events are in agreement with visual observations at Neumayer III station. The BSD algorithm detects heavy blowing snow 36 % of the time at Neumayer (2011–2015) and 13 % at PE station (2010–2016). Blowing snow occurrence peaks during the austral winter and shows around 5 % interannual variability. The BSD algorithm is capable of detecting blowing snow both lifted from the ground and occurring during precipitation, which is an added value since results indicate that 92 % of the blowing snow is during synoptic events, often combined with precipitation. Analysis of atmospheric meteorological variables shows that blowing snow occurrence strongly depends on fresh snow availability in addition to wind speed. This finding challenges the commonly used parametrizations, where the threshold for snow particles to be lifted is a function of wind speed only. Blowing snow occurs predominantly during storms and overcast conditions, shortly after precipitation events, and can reach up to 1300 m a. g. l.  in the case of heavy mixed events (precipitation and blowing snow together). These results suggest that synoptic conditions play an important role in generating blowing snow events and that fresh snow availability should be considered in determining the blowing snow onset.

scholarly journals A Mobile, Multichannel, UWB Radar for Potential Ice Core Drill Site Identification in East Antarctica: Development and First Results

2020 ◽  
Vol 13 ◽  
pp. 4836-4847
Author(s):  
Fernando Rodriguez-Morales ◽  
David Braaten ◽  
Hoang Trong Mai ◽  
John Paden ◽  
Prasad Gogineni ◽  
...  
Keyword(s):  
Ice Core ◽  
East Antarctica ◽  
Uwb Radar ◽  
Drill Site ◽  
First Results ◽  
Site Identification

scholarly journals Temporal and spatial variability of surface mass balance at Dome Fuji, East Antarctica, by the stake method from 1995 to 2006

2008 ◽  
Vol 54 (184) ◽  
pp. 107-116 ◽  
Author(s):  
Takao Kameda ◽  
Hideaki Motoyama ◽  
Shuji Fujita ◽  
Shuhei Takahashi
Keyword(s):  
Mass Balance ◽  
Ice Core ◽  
Snow Accumulation ◽  
East Antarctica ◽  
Surface Mass Balance ◽  
Surface Mass ◽  
Frequency Distributions ◽  
Temporal And Spatial Variability ◽  
The Antarctic ◽  
Height Data

AbstractThe surface mass balance (SMB) at Dome Fuji, East Antarctica, was estimated using 36 bamboo stakes (grid of 6 × 6, placed at 20 m intervals) from 1995 to 2006. The heights of the stake tops from the snow surface were measured at 0.5 cm resolution twice monthly in 1995, 1996, 1997 and 2003, and once a year for the rest of the study period. To account for snow settling, the average snow density at the stake base during the measurements was used for converting the stake-height data to SMB. The annual SMB from 1995 to 2006 at Dome Fuji was 27.3 ± 1.5 kg m−2 a−1. This result agrees well with the annual SMB from AD 1260 to 1993 (26.4 kg m−2 a−1) estimated from volcanic signals in the Dome Fuji ice core. Over the period 1995–2006, there were 37 (8.6% of the measurements) negative or zero annual SMB results. Variation in the multi-year averages of annual SMB decreased with the square root of the number of observation years, and 10 years of observations of a single stake allowed the estimation of annual SMB at ±10% accuracy. The frequency distributions of annual and monthly SMB were examined. The findings clarify the complex behavior of the annual and monthly SMB at Dome Fuji, which will be common phenomena in areas of low snow accumulation of the interior of the Antarctic ice sheet.

scholarly journals Snowfall and Water Stable Isotope Variability in East Antarctica Controlled by Warm Synoptic Events

2020 ◽  
Vol 125 (17) ◽  
Author(s):  
Aymeric P. M. Servettaz ◽  
Anais J. Orsi ◽  
Mark A. J. Curran ◽  
Andrew D. Moy ◽  
Amaelle Landais ◽  
...  
Keyword(s):  
Stable Isotope ◽  
East Antarctica ◽  
Water Stable Isotope

scholarly journals Density measurements in ice boreholes using neutron scattering

2003 ◽  
Vol 49 (167) ◽  
pp. 599-604 ◽  
Author(s):  
Elizabeth M. Morris ◽  
J. David Cooper
Keyword(s):  
Neutron Scattering ◽  
Count Rate ◽  
Fast Neutrons ◽  
Potential Contribution ◽  
Snow Density ◽  
Hydrogen Atoms ◽  
Density Profiles ◽  
Annual Variations ◽  
Neutron Probe ◽  
Calibration Equations

AbstractThis paper describes the use of a neutron probe to measure detailed stratigraphy in ice and snow. The Wallingford neutron probe, developed for measurement of soil moisture, consists of an annular radioactive source of fast neutrons around the centre of a cylindrical detector for slow (thermal) neutrons. In snow and ice, the fast neutrons lose energy by scattering from hydrogen atoms, and the number of slow neutrons arriving at the detector (the count rate) is related to the density of the medium. Calibration equations for count rate as a function of snow density and borehole diameter have been derived. Snow-density profiles from boreholes obtained using the probe show that, despite the smoothing produced by the neutron-scattering process, annual variations in density can be resolved. The potential contribution of the neutron probe to improvements in mass-balance monitoring is discussed.

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