scholarly journals Ground-based measurements of spatial and temporal variability of snow accumulation in East Antarctica

2008 ◽  
Vol 46 (2) ◽  
Author(s):  
Olaf Eisen ◽  
Massimo Frezzotti ◽  
Christophe Genthon ◽  
Elisabeth Isaksson ◽  
Olivier Magand ◽  
...  
2005 ◽  
Vol 51 (172) ◽  
pp. 113-124 ◽  
Author(s):  
Massimo Frezzotti ◽  
Michel Pourchet ◽  
Onelio Flora ◽  
Stefano Gandolfi ◽  
Michel Gay ◽  
...  

AbstractRecent snow accumulation rate is a key quantity for ice-core and mass-balance studies. Several accumulation measurement methods (stake farm, fin core, snow-radar profiling, surface morphology, remote sensing) were used, compared and integrated at eight sites along a transect from Terra Nova Bay to Dome C, East Antarctica, to provide information about the spatial and temporal variability of snow accumulation. Thirty-nine cores were dated by identifying tritium/b marker levels (1965_66) and non-sea-salt (nss) SO42_ spikes of the Tambora (Indonesia) volcanic event (1816) in order to provide information on temporal variability. Cores were linked by snow radar and global positioning system surveys to provide detailed information on spatial variability in snow accumulation. Stake-farm and ice-core accumulation rates are observed to differ significantly, but isochrones (snow radar) correlate well with ice-core derived accumulation. The accumulation/ablation pattern from stake measurements suggests that the annual local noise (metre scale) in snow accumulation can approach 2 years of ablation and more than four times the average annual accumulation, with no accumulation or ablation for a 5 year period in up to 40% of cases. The spatial variability of snow accumulation at the kilometre scale is one order of magnitude higher than temporal variability at the multi-decadal/secular scale. Stake measurements and firn cores at Dome C confirm an approximate 30% increase in accumulation over the last two centuries, with respect to the average over the last 5000 years


2011 ◽  
Vol 5 (4) ◽  
pp. 2061-2114 ◽  
Author(s):  
S. Fujita ◽  
P. Holmlund ◽  
I. Andersson ◽  
I. Brown ◽  
H. Enomoto ◽  
...  

Abstract. To better understand the spatio-temporal variability of the glaciological environment in Dronning Maud Land (DML), East Antarctica, investigations were carried out along the 2800-km-long Japanese-Swedish IPY 2007/2008 traverse. The route covers ice sheet ridges and two deep ice coring sites at Dome Fuji and EPICA DML. The surface mass balance (SMB) distribution was derived based on analysis of isochrones within snow pits, firn cores and subsurface radar signals. The SMB averaged over various time scales in the Holocene was determined. This was then compared with various glaciological data. We find that the large-scale distribution of the SMB depends on the surface elevation, continentality and interactions between ice sheet ridges and the prevailing counterclockwise windfield in DML. A different SMB is found for the windward and leeward sides of the ridges. Local-scale variability in the SMB is essentially governed by bedrock topography which determines the local surface topography. In the eastern part of DML, the accumulation rate in the second half of the 20th century is found to be higher by 15 % compared to averages over longer periods of 722 a or 7.9 ka before AD 2008. A similar trend has been reported for many inland plateau sites in East Antarctica.


2012 ◽  
Vol 6 (6) ◽  
pp. 1345-1358 ◽  
Author(s):  
D. Verfaillie ◽  
M. Fily ◽  
E. Le Meur ◽  
O. Magand ◽  
B. Jourdain ◽  
...  

Abstract. The mass balance of ice sheets is an intensively studied topic in the context of global change and sea-level rise. However – particularly in Antarctica – obtaining mass balance estimates remains difficult due to various logistical problems. In the framework of the TASTE-IDEA (Trans-Antarctic Scientific Traverses Expeditions – Ice Divide of East Antarctica) program, an International Polar Year project, continuous ground penetrating radar (GPR) measurements were carried out during a traverse in Adelie Land (East Antarctica) during the 2008–2009 austral summer between the Italian–French Dome C (DC) polar plateau site and French Dumont D'Urville (DdU) coastal station. The aim of this study was to process and interpret GPR data in terms of snow accumulation, to analyse its spatial and temporal variability and compare it with historical data and modelling. The focus was on the last 300 yr, from the pre-industrial period to recent times. Beta-radioactivity counting and gamma spectrometry were applied to cores at the LGGE laboratory, providing a depth–age calibration for radar measurements. Over the 600 km of usable GPR data, depth and snow accumulation were determined with the help of three distinct layers visible on the radargrams (≈ 1730, 1799 and 1941 AD). Preliminary results reveal a gradual increase in accumulation towards the coast (from ≈ 3 cm w.e. a−1 at Dome C to ≈ 17 cm w.e. a−1 at the end of the transect) and previously undocumented undulating structures between 300 and 600 km from DC. Results agree fairly well with data from previous studies and modelling. Drawing final conclusions on temporal variations is difficult because of the margin of error introduced by density estimation. This study should have various applications, including model validation.


2012 ◽  
Vol 6 (4) ◽  
pp. 2855-2889 ◽  
Author(s):  
D. Verfaillie ◽  
M. Fily ◽  
E. Le Meur ◽  
O. Magand ◽  
B. Jourdain ◽  
...  

Abstract. Polar ice sheets mass balance is a timely topic intensively studied in the context of global change and sea-level rise. However, obtaining mass balance estimates in Antarctica in particular, remains difficult due to various logistical problems. In the framework of the TASTE-IDEA program, labeled as an International Polar Year project, continuous Ground Penetrating Radar (GPR) measurements were carried out during a traverse realised in Adelie Land (East Antarctica) during the 2008–2009 austral summer between the Italo-French Dome C (DC) polar plateau site and French Dumont D'Urville (DdU) coastal station. The aim of this study was to process and interpret GPR data in terms of snow accumulation, to analyse its spatial and temporal variability along the DC-DdU traverse and compare it with historical data and modeling. The emphasis has been put on the last 300 yr, from the pre-industrial to recent time period. Beta-radioactivity counting and gamma spectrometry were studied in cores at LGGE laboratory, providing a depth-age calibration for radar measurements. Over the 600 km of usable GPR data, depth and snow accumulation were determined with the help of three distinct layers visible on the radargrams (≈1730, 1799 and 1941 AD). Preliminary results reveal a gradual accumulation increase towards the coast and the occurrence of previously undocumented undulating structures between 300 and 600 km from DC. Results agree fairly well with data from previous studies and modeling. Concluding on temporal variations is difficult because of the margin of error introduced by density estimation. This study should have various applications such as for model validation.


2004 ◽  
Vol 50 (168) ◽  
pp. 137-146 ◽  
Author(s):  
Fidan Traufetter ◽  
Hans Oerter ◽  
Hubertus Fischer ◽  
Rolf Weller ◽  
Heinz Miller

AbstractIn the framework of the European Project for Ice Coring in Antarctica (EPICA), a comprehensive glaciological pre-site survey has been carried out on Amundsenisen, Dronning Maud Land, East Antarctica, in the past decade. Within this survey, four intermediate-depth ice cores and 13 snow pits were analyzed for their ionic composition and interpreted with respect to the spatial and temporal variability of volcanic sulphate deposition. The comparison of the non-sea-salt (nss)-sulphate peaks that are related to the well-known eruptions of Pinatubo and Cerro Hudson in AD 1991 revealed sulphate depositions of comparable size (15.8±3.4 kg km–2) in 11 snow pits. There is a tendency to higher annual concentrations for smaller snow-accumulation rates. The combination of seasonal sodium and annually resolved nss-sulphate records allowed the establishment of a time-scale derived by annual-layer counting over the last 2000 years and thus a detailed chronology of annual volcanic sulphate deposition. Using a robust outlier detection algorithm, 49 volcanic eruptions were identified between AD 165 and 1997. The dating uncertainty is ±3 years between AD 1997 and 1601, around ±5 years between AD 1601 and 1257, and increasing to ±24 years at AD 165, improving the accuracy of the volcanic chronology during the penultimate millennium considerably.


2011 ◽  
Vol 5 (4) ◽  
pp. 1057-1081 ◽  
Author(s):  
S. Fujita ◽  
P. Holmlund ◽  
I. Andersson ◽  
I. Brown ◽  
H. Enomoto ◽  
...  

Abstract. To better understand the spatio-temporal variability of the glaciological environment in Dronning Maud Land (DML), East Antarctica, a 2800-km-long Japanese-Swedish traverse was carried out. The route includes ice divides between two ice-coring sites at Dome Fuji and EPICA DML. We determined the surface mass balance (SMB) averaged over various time scales in the late Holocene based on studies of snow pits and firn cores, in addition to radar data. We find that the large-scale distribution of the SMB depends on the surface elevation and continentality, and that the SMB differs between the windward and leeward sides of ice divides for strong-wind events. We suggest that the SMB is highly influenced by interactions between the large-scale surface topography of ice divides and the wind field of strong-wind events that are often associated with high-precipitation events. Local variations in the SMB are governed by the local surface topography, which is influenced by the bedrock topography. In the eastern part of DML, the accumulation rate in the second half of the 20th century is found to be higher by ~15 % than averages over longer periods of 722 a or 7.9 ka before AD 2008. A similar increasing trend has been reported for many inland plateau sites in Antarctica with the exception of several sites on the leeward side of the ice divides.


2021 ◽  
Author(s):  
Alexander Raphael Groos ◽  
Christoph Mayer ◽  
Astrid Lambrecht ◽  
Sabrina Erlwein ◽  
Margit Schwikowski

<p>The Karakoram is an extensively glacierised mountain range in the western part of High Mountain Asia and constitutes an important source of fresh water for millions of people in the Indus Basin. Over the last years, the Karakoram has attracted increasing attention due to an anomalous glacier stability, which contrasts the progressing ice mass loss across the Himalaya. Decreasing summer temperatures and increasing winter precipitation have been proposed as potential causes for the anomaly. However, the lack of snow accumulation studies and long-term meteorological measurements above 3,000 m a.s.l. hampers the corroboration of this hypothesis. To quantify the spatial and temporal variability of snow accumulation in the central Karakoram, we followed the track of a Canadian research expedition from 1986. We reinvestigated eight sites between ca. 4,400 and 5,200 m a.s.l. in the connected accumulation zone of the Biafo and Hispar glaciers in 2019. Density measurements were performed in each snow pit down to the summer horizon of the previous year to quantify the elevation-dependent amount of annually accumulated snow. In addition, snow samples were collected from three selected pits for the analysis of rare earth elements and stable water isotopes to constrain the origin and seasonality of the deposited snow. Finally, we compared our recent measurements with the 30-year-old results from the Canadian research expedition as well as independent meteorological data.  In doing so we aim to evaluate the hypothesised increase in winter precipitation in this region.</p>


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