scholarly journals How does the ice sheet surface mass balance relate to snowfall? Insights from a ground-based precipitation radar in East Antarctica

2017 ◽  
Author(s):  
Niels Souverijns ◽  
Alexandra Gossart ◽  
Irina V. Gorodetskaya ◽  
Stef Lhermitte ◽  
Alexander Mangold ◽  
...  
Keyword(s):  
Mass Balance ◽  
Ice Sheet ◽  
Local Scale ◽  
East Antarctica ◽  
Surface Mass Balance ◽  
Clear Understanding ◽  
Surface Mass ◽  
Drifting Snow ◽  
Dronning Maud Land ◽  
Good Proxy

Abstract. Local surface mass balance (SMB) measurements are crucial for understanding changes in the total mass of the Antarctic Ice Sheet, including its contribution to sea level rise. Despite continuous attempts to decipher mechanisms controlling the local SMB, a clear understanding of the separate components is still lacking, while snowfall measurements are almost absent. In this study, the different terms are quantified at the Princess Elisabeth (PE) station in Dronning Maud Land, East Antarctica. Furthermore, the relation between snowfall and accumulation at the surface is investigated. To achieve this, a unique collocated set of remote sensing instrumentation (Micro Rain Radar, ceilometer, Automatic Weather Station, among others) was established operating for an unprecedented time period of 37 months. Snowfall originates mainly from moist and warm air advected from lower latitudes associated with cyclone activity. However, snowfall events are much more common than accumulation events. During 38 % of the snowfall cases observed, the freshly-fallen snow is ablated by the wind during the course of the event. Generally, snow storms of longer duration have a higher chance to attain for accumulation at the local scale, while shorter events usually attain for ablation (on average 17 and 12 hours respectively). As such, SMB records cannot be considered a good proxy for snowfall at the local scale. Accumulation and ablation also occur during non-snowfall conditions. A large part of the accumulation at the station takes place when preceding snowfall events were occurring in upstream coastal areas. This fresh snow is easily picked up and transported in shallow drifting snow layers to more inland locations, even when wind speed is relatively low (

scholarly journals How does the ice sheet surface mass balance relate to snowfall? Insights from a ground-based precipitation radar in East Antarctica

2018 ◽  
Vol 12 (6) ◽  
pp. 1987-2003 ◽  
Author(s):  
Niels Souverijns ◽  
Alexandra Gossart ◽  
Irina V. Gorodetskaya ◽  
Stef Lhermitte ◽  
Alexander Mangold ◽  
...  
Keyword(s):  
Mass Balance ◽  
Ice Sheet ◽  
East Antarctica ◽  
Surface Mass Balance ◽  
Clear Understanding ◽  
Surface Mass ◽  
Wind Speeds ◽  
Drifting Snow ◽  
Set Up ◽  
The Antarctic

Abstract. Local surface mass balance (SMB) measurements are crucial for understanding changes in the total mass of the Antarctic Ice Sheet, including its contribution to sea level rise. Despite continuous attempts to decipher mechanisms controlling the local and regional SMB, a clear understanding of the separate components is still lacking, while snowfall measurements are almost absent. In this study, the different terms of the SMB are quantified at the Princess Elisabeth (PE) station in Dronning Maud Land, East Antarctica. Furthermore, the relationship between snowfall and accumulation at the surface is investigated. To achieve this, a unique collocated set of ground-based and in situ remote sensing instrumentation (Micro Rain Radar, ceilometer, automatic weather station, among others) was set up and operated for a time period of 37 months. Snowfall originates mainly from moist and warm air advected from lower latitudes associated with cyclone activity. However, snowfall events are not always associated with accumulation. During 38 % of the observed snowfall cases, the freshly fallen snow is ablated by the wind during the course of the event. Generally, snow storms of longer duration and larger spatial extent have a higher chance of resulting in accumulation on a local scale, while shorter events usually result in ablation (on average 17 and 12 h respectively). A large part of the accumulation at the station takes place when preceding snowfall events were occurring in synoptic upstream areas. This fresh snow is easily picked up and transported in shallow drifting snow layers over tens of kilometres, even when wind speeds are relatively low (< 7 ms−1). Ablation events are mainly related to katabatic winds originating from the Antarctic plateau and the mountain ranges in the south. These dry winds are able to remove snow and lead to a decrease in the local SMB. This work highlights that the local SMB is strongly influenced by synoptic upstream conditions.

scholarly journals Surface and snowdrift sublimation at Princess Elisabeth station, East Antarctica

2012 ◽  
Vol 6 (4) ◽  
pp. 841-857 ◽  
Author(s):  
W. Thiery ◽  
I. V. Gorodetskaya ◽  
R. Bintanja ◽  
N. P. M. Van Lipzig ◽  
M. R. Van den Broeke ◽  
...  
Keyword(s):  
Mass Balance ◽  
East Antarctica ◽  
Lower Probability ◽  
Research Station ◽  
Surface Mass Balance ◽  
Surface Mass ◽  
Drifting Snow ◽  
Dronning Maud Land ◽  
Meteorological Observations ◽  
Strong Winds

Abstract. In the near-coastal regions of Antarctica, a significant fraction of the snow precipitating onto the surface is removed again through sublimation – either directly from the surface or from drifting snow particles. Meteorological observations from an Automatic Weather Station (AWS) near the Belgian research station Princess Elisabeth in Dronning Maud Land, East-Antarctica, are used to study surface and snowdrift sublimation and to assess their impacts on both the surface mass balance and the surface energy balance during 2009 and 2010. Comparison to three other AWSs in Dronning Maud Land with 11 to 13 yr of observations shows that sublimation has a significant influence on the surface mass balance at katabatic locations by removing 10–23% of their total precipitation, but at the same time reveals anomalously low surface and snowdrift sublimation rates at Princess Elisabeth (17 mm w.e. yr−1 compared to 42 mm w.e. yr−1 at Svea Cross and 52 mm w.e. yr−1 at Wasa/Aboa). This anomaly is attributed to local topography, which shields the station from strong katabatic influence, and, therefore, on the one hand allows for a strong surface inversion to persist throughout most of the year and on the other hand causes a lower probability of occurrence of intermediately strong winds. This wind speed class turns out to contribute most to the total snowdrift sublimation mass flux, given its ability to lift a high number of particles while still allowing for considerable undersaturation.

scholarly journals Surface and snowdrift sublimation at Princess Elisabeth station, East Antarctica

2012 ◽  
Vol 6 (2) ◽  
pp. 1491-1530
Author(s):  
W. Thiery ◽  
I. V. Gorodetskaya ◽  
R. Bintanja ◽  
N. P. M. van Lipzig ◽  
M. R. van den Broeke ◽  
...  
Keyword(s):  
Mass Balance ◽  
East Antarctica ◽  
Lower Probability ◽  
Research Station ◽  
Surface Mass Balance ◽  
Surface Mass ◽  
Drifting Snow ◽  
Dronning Maud Land ◽  
Meteorological Observations ◽  
Strong Winds

Abstract. In the near-coastal regions of Antarctica, a significant fraction of the snow precipitating onto the surface is removed again through sublimation – either directly from the surface or from drifting snow particles. Meteorological observations from an Automatic Weather Station (AWS) near the Belgian research station Princess Elisabeth in Dronning Maud Land, East-Antarctica, are used to study surface and snowdrift sublimation and to assess their impacts on both the surface mass balance and the surface energy balance. Comparison to three other AWSs in Dronning Maud Land shows that sublimation has a significant influence on the surface mass balance at katabatic locations by removing 10–23 % of their total precipitation, but at the same time reveals anomalously low surface and snowdrift sublimation rates at Princess Elisabeth (18 mm w.e. yr–1 compared to 42 mm w.e. yr–1 at Svea Cross and 52 mm w.e. yr–1 at Wasa/Aboa). This anomaly is attributed to local topography, which shields the station from strong katabatic influence, and therefore on the one hand allows for a strong surface inversion to persist throughout most of the year and on the other hand causes a lower probability of occurrence of intermediately strong winds. These wind speed classes turn out to contribute most to the total snowdrift sublimation mass flux, given their ability to lift a high number of particles while still allowing for considerable undersaturation.

scholarly journals Estimation of the Antarctic surface mass balance using MAR (1979–2015) and identification of dominant processes

2018 ◽  
Author(s):  
Cécile Agosta ◽  
Charles Amory ◽  
Christoph Kittel ◽  
Anais Orsi ◽  
Vincent Favier ◽  
...  
Keyword(s):  
Mass Balance ◽  
Climate Models ◽  
Regional Climate ◽  
Ice Sheet ◽  
Snow Accumulation ◽  
Surface Mass Balance ◽  
Ice Dynamics ◽  
Surface Mass ◽  
Drifting Snow ◽  
The Antarctic

Abstract. The Antarctic ice sheet mass balance is a major component of the sea level budget and results from the difference of two fluxes of a similar magnitude: ice flow discharging in the ocean and net snow accumulation on the ice sheet surface, i.e. the surface mass balance (SMB). Separately modelling ice dynamics and surface mass balance is the only way to project future trends. In addition, mass balance studies frequently use regional climate models (RCMs) outputs as an alternative to observed fields because SMB observations are particularly scarce on the ice sheet. Here we evaluate new simulations of the polar RCM MAR forced by three reanalyses, ERA-Interim, JRA-55 and MERRA2, for the period 1979–2015, and we compare our results to the last outputs of the RCM RACMO2 forced by ERA-Interim. We show that MAR and RACMO2 perform similarly well in simulating coast to plateau SMB gradients, and we find no significant differences in their simulated SMB when integrated over the ice sheet or its major basins. More importantly, we outline and quantify missing processes in both RCMs. Along stake transects, we show that both models accumulate too much snow on crests, and not enough snow in valleys, as a result of erosion-deposition processes not included in MAR, where the drifting snow module has been switched off, and probably underestimated in RACMO2 by a factor of three. As a consequence, the amount of drifting snow sublimating in the atmospheric boundary layer remains a potentially large mass sink needed to be better constrained. Moreover, MAR generally simulates larger SMB and snowfall amounts than RACMO2 inland, whereas snowfall rates are significantly lower in MAR than in RACMO2 at the ice sheet margins. This divergent behaviour at the margins results from differences in model parameterisations, as MAR explicitly advects precipitating particles through the atmospheric layers and sublimates snowflakes in the undersaturated katabatic layer, whereas in RACMO2 precipitation is added to the surface without advection through the atmosphere. Consequently, we corroborate a recent study concluding that sublimation of precipitation in the low-level atmospheric layers is a significant mass sink for the Antarctic SMB, as it may represent ∼ 240 ± 25 Gt yr-1 of difference in snowfall between RACMO2 and MAR for the period 1979–2015, which is 10 % of the simulated snowfall loaded on the ice sheet and more than twice the surface snow sublimation as currently simulated by MAR.

scholarly journals Climate variables along a traverse line in Dronning Maud Land, East Antarctica

1999 ◽  
Vol 45 (150) ◽  
pp. 295-302 ◽  
Author(s):  
Michiel R. van den Broeke ◽  
Jan-Gunnar Winther ◽  
Elisabeth Isaksson ◽  
Jean Francis Pinglot ◽  
Lars Karlöf ◽  
...  
Keyword(s):  
Potential Temperature ◽  
Ice Sheet ◽  
High Elevation ◽  
Cold Climate ◽  
East Antarctica ◽  
Katabatic Wind ◽  
Near Surface ◽  
Surface Mass ◽  
Drifting Snow ◽  
Dronning Maud Land

AbstractTemperature, density and accumulation data were obtained from shallow firn cores, drilled during an overland traverse through a previously unknown part of Dronning Maud Land, East Antarctica. The traverse area is characterised by high mountains that obstruct the ice flow, resulting in a sudden transition from the polar plateau to the coastal region. The spatial variations of potential temperature, near-surface firn density and accumulation suggest that katabatic winds are active in this region. Proxy wind data derived from firn-density profiles confirm that annual mean wind speed is strongly related to the magnitude of the surface slope. The high elevation of the ice sheet south of the mountains makes for a dry, cold climate, in which mass loss owing to sublimation is small and erosion of snow by the wind has a potentially large impact on the surface mass balance. A simple katabatic-wind model is used to explain the variations of accumulation along the traverse line in terms of divergence/convergence of the local transport of drifting snow. The resulting wind- and snowdrift patterns are closely connected to the topography of the ice sheet: ridges are especially sensitive to erosion, while ice streams and other depressions act as collectors of drifting snow.

scholarly journals A new approach to estimate ice dynamic rates using satellite observations in East Antarctica

2016 ◽  
Author(s):  
Bianca Kallenberg ◽  
Paul Tregoning ◽  
Janosch F. Hoffmann ◽  
Rhys Hawkins ◽  
Anthony Purcell ◽  
...  
Keyword(s):  
Mass Balance ◽  
Satellite Altimetry ◽  
Ice Sheet ◽  
East Antarctica ◽  
Surface Mass Balance ◽  
Antarctic Ice Sheet ◽  
Surface Mass ◽  
Elevation Changes ◽  
Ice Sheet Mass Balance ◽  
The Antarctic

Abstract. Mass balance changes of the Antarctic ice sheet are of significant interest due to its sensitivity to climatic changes and its contribution to changes in global sea level. While regional climate models successfully estimate mass input due to snowfall, it remains difficult to estimate the amount of mass loss due to ice dynamic processes. It's often been assumed that changes in ice dynamic rates only need to be considered when assessing long term ice sheet mass balance; however, two decades of satellite altimetry observations reveal that the Antarctic ice sheet changes unexpectedly and much more dynamically than previously expected. Despite available estimates on ice dynamic rates obtained from radar altimetry, information about changes in ice dynamic rates are still limited, especially in East Antarctica. Without understanding ice dynamic rates it is not possible to properly assess changes in ice sheet mass balance, surface elevation or to develop ice sheet models. In this study we investigate the possibility of estimating ice dynamic rates by removing modelled rates of surface mass balance, firn compaction and bedrock uplift from satellite altimetry and gravity observations. With similar rates of ice discharge acquired from two different satellite missions we show that it is possible to obtain an approximation of ice dynamic rates by combining altimetry and gravity observations. Thus, surface elevation changes due to surface mass balance, firn compaction and ice dynamic rates can be modelled and correlate with observed elevation changes from satellite altimetry.

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

2015 ◽  
Vol 11 (1) ◽  
pp. 377-405 ◽  
Author(s):  
F. Parrenin ◽  
S. Fujita ◽  
A. Abe-Ouchi ◽  
K. Kawamura ◽  
V. Masson-Delmotte ◽  
...  
Keyword(s):  
Mass Balance ◽  
Ice Core ◽  
Ice Sheet ◽  
Ice Cores ◽  
Atmospheric Modeling ◽  
East Antarctica ◽  
Surface Mass Balance ◽  
Last Interglacial ◽  
Surface Mass ◽  
The Past

Abstract. Documenting 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. Here we reconstruct the 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 synchronisation of the two ice cores and on corrections for the vertical thinning of layers. During the past 216 000 years, this SMB ratio, denoted SMBEDC/SMBDF, varied between 0.7 and 1.1, decreasing during cold periods and increasing during warm periods. While past climatic changes have been depicted as homogeneous along the East Antarctic Plateau, our results reveal larger amplitudes of changes in SMB at EDC compared to DF, consistent with previous results showing larger amplitudes of changes in water stable isotopes and estimated surface temperature at EDC compared to DF. Within interglacial periods and during the last glacial inception (Marine Isotope Stages, MIS-5c and MIS-5d), the SMB ratio deviates by up to 30% 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. These SMB ratio changes not closely related to isotopic changes are one of the possible causes of the observed gaps between the ice core chronologies at DF and EDC. Such changes in SMB ratio may have been caused by (i) climatic processes related to changes in air mass trajectories and local climate, (ii) glaciological processes associated with relative elevation changes, or (iii) a combination of climatic and glaciological processes, such as the interaction between changes in accumulation and in the position of the domes. Our inferred SMB ratio history has important implications for ice sheet modeling (for which SMB is a boundary condition) or atmospheric modeling (our inferred SMB ratio could serve as a test).

scholarly journals A new approach to estimate ice dynamic rates using satellite observations in East Antarctica

2017 ◽  
Vol 11 (3) ◽  
pp. 1235-1245 ◽  
Author(s):  
Bianca Kallenberg ◽  
Paul Tregoning ◽  
Janosch Fabian Hoffmann ◽  
Rhys Hawkins ◽  
Anthony Purcell ◽  
...  
Keyword(s):  
Mass Balance ◽  
Satellite Altimetry ◽  
Ice Sheet ◽  
East Antarctica ◽  
Surface Mass Balance ◽  
Ice Dynamics ◽  
Surface Mass ◽  
Elevation Changes ◽  
Ice Sheet Mass Balance ◽  
The Antarctic

Abstract. Mass balance changes of the Antarctic ice sheet are of significant interest due to its sensitivity to climatic changes and its contribution to changes in global sea level. While regional climate models successfully estimate mass input due to snowfall, it remains difficult to estimate the amount of mass loss due to ice dynamic processes. It has often been assumed that changes in ice dynamic rates only need to be considered when assessing long-term ice sheet mass balance; however, 2 decades of satellite altimetry observations reveal that the Antarctic ice sheet changes unexpectedly and much more dynamically than previously expected. Despite available estimates on ice dynamic rates obtained from radar altimetry, information about ice sheet changes due to changes in the ice dynamics are still limited, especially in East Antarctica. Without understanding ice dynamic rates, it is not possible to properly assess changes in ice sheet mass balance and surface elevation or to develop ice sheet models. In this study we investigate the possibility of estimating ice sheet changes due to ice dynamic rates by removing modelled rates of surface mass balance, firn compaction, and bedrock uplift from satellite altimetry and gravity observations. With similar rates of ice discharge acquired from two different satellite missions we show that it is possible to obtain an approximation of the rate of change due to ice dynamics by combining altimetry and gravity observations. Thus, surface elevation changes due to surface mass balance, firn compaction, and ice dynamic rates can be modelled and correlated with observed elevation changes from satellite altimetry.

scholarly journals Impact of model resolution on simulated wind, drifting snow and surface mass balance in Terre Adélie, East Antarctica

2012 ◽  
Vol 58 (211) ◽  
pp. 821-829 ◽  
Author(s):  
Jan T.M. Lenaerts ◽  
Michiel R. Van Den Broeke ◽  
Claudio Scarchilli ◽  
Cécile Agosta
Keyword(s):  
Wind Speed ◽  
Mass Balance ◽  
East Antarctica ◽  
Surface Mass Balance ◽  
Model Resolution ◽  
Surface Mass ◽  
Drifting Snow ◽  
Victoria Land ◽  
Terre Adélie ◽  
Simulated Wind

AbstractThis paper presents the impact of model resolution on the simulated wind speed, drifting snow climate and surface mass balance (SMB) of Terre Adélie and its surroundings, East Antarctica. We compare regional climate model simulations at 27 and 5.5 km resolution for the year 2009. The wind speed maxima in Terre Adélie and the narrow glacial valleys of Victoria Land are better represented at 5.5 km resolution, because the topography is better resolved. Drifting snow sublimation is >100 mm a-1 in regions with high wind speeds. Our results indicate a strong feedback between topography, wind gradients and drifting snow erosion. As a result, SMB shows much more local spatial variability at 5.5 km resolution that is controlled by drifting snow erosion, whereas the large-scale SMB gradient is largely determined by precipitation. Drifting snow processes lead to ablation in the narrow glacial valleys of Victoria Land. The integrated SMB equals 86 Gt. Although wind climate, drifting snow processes and SMB variability are better represented at 5.5 km, the area-integrated SMB is not significantly different between the simulations at 27 and 5.5 km. A horizontal resolution of 27 km is sufficient to realistically simulate ice-sheet wide SMB.

scholarly journals Performance of MAR (v3.11) in simulating the drifting-snow climate and surface mass balance of Adélie Land, East Antarctica

2021 ◽  
Vol 14 (6) ◽  
pp. 3487-3510
Author(s):  
Charles Amory ◽  
Christoph Kittel ◽  
Louis Le Toumelin ◽  
Cécile Agosta ◽  
Alison Delhasse ◽  
...  
Keyword(s):  
Mass Balance ◽  
Climate Models ◽  
Climate Model ◽  
Comprehensive Evaluation ◽  
Regional Climate ◽  
East Antarctica ◽  
Surface Mass Balance ◽  
Near Surface ◽  
Surface Mass ◽  
Drifting Snow

Abstract. Drifting snow, or the wind-driven transport of snow particles originating from clouds and the surface below and above 2 m above ground and their concurrent sublimation, is a poorly documented process on the Antarctic ice sheet, which is inherently lacking in most climate models. Since drifting snow mostly results from erosion of surface particles, a comprehensive evaluation of this process in climate models requires a concurrent assessment of simulated drifting-snow transport and the surface mass balance (SMB). In this paper a new version of the drifting-snow scheme currently embedded in the regional climate model MAR (v3.11) is extensively described. Several important modifications relative to previous version have been implemented and include notably a parameterization for drifting-snow compaction of the uppermost snowpack layer, differentiated snow density at deposition between precipitation and drifting snow, and a rewrite of the threshold friction velocity above which snow erosion initiates. Model results at high resolution (10 km) over Adélie Land, East Antarctica, for the period 2004–2018 are presented and evaluated against available near-surface meteorological observations at half-hourly resolution and annual SMB estimates. The evaluation demonstrates that MAR resolves the local drifting-snow frequency and transport up to the scale of the drifting-snow event and captures the resulting observed climate and SMB variability, suggesting that this model version can be used for continent-wide applications.

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