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

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.

Download Full-text

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

10.5194/tc-2017-246 ◽

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 (

Download Full-text

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

10.5194/tc-2018-76 ◽

2018 ◽

Cited By ~ 4

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.

Download Full-text

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

10.5194/tc-2016-269 ◽

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.

Download Full-text

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

The Cryosphere ◽

10.5194/tc-11-1235-2017 ◽

2017 ◽

Vol 11 (3) ◽

pp. 1235-1245 ◽

Cited By ~ 2

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.

Download Full-text

Estimation of the Antarctic surface mass balance using the regional climate model MAR (1979–2015) and identification of dominant processes

The Cryosphere ◽

10.5194/tc-13-281-2019 ◽

2019 ◽

Vol 13 (1) ◽

pp. 281-296 ◽

Cited By ~ 51

Author(s):

Cécile Agosta ◽

Charles Amory ◽

Christoph Kittel ◽

Anais Orsi ◽

Vincent Favier ◽

...

Keyword(s):

Mass Balance ◽

Climate Models ◽

Regional Climate ◽

Ice Sheet ◽

Surface Mass Balance ◽

Ice Dynamics ◽

Surface Mass ◽

Drifting Snow ◽

The Antarctic ◽

Snow Transport

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 SMB 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 MERRA-2, for the period 1979–2015, and we compare MAR 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 or underestimated 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 drifting snow transport fluxes not included in MAR and probably underestimated in RACMO2 by a factor of 3. Our results tend to confirm that drifting snow transport and sublimation fluxes are much larger than previous model-based estimates and need to be better resolved and constrained in climate models. Sublimation of precipitating particles in low-level atmospheric layers is responsible for the significantly lower snowfall rates in MAR than in RACMO2 in katabatic channels at the ice sheet margins. Atmospheric sublimation in MAR represents 363 Gt yr−1 over the grounded ice sheet for the year 2015, which is 16 % of the simulated snowfall loaded at the ground. This estimate is consistent with a recent study based on precipitation radar observations and is more than twice as much as simulated in RACMO2 because of different time residence of precipitating particles in the atmosphere. The remaining spatial differences in snowfall between MAR and RACMO2 are attributed to differences in advection of precipitation with snowfall particles being likely advected too far inland in MAR.

Download Full-text

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

Journal of Glaciology ◽

10.3189/002214308784409062 ◽

2008 ◽

Vol 54 (184) ◽

pp. 107-116 ◽

Cited By ~ 60

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.

Download Full-text

An Evaluation of Surface Climatology in State-of-the-Art Reanalyses over the Antarctic Ice Sheet

Journal of Climate ◽

10.1175/jcli-d-19-0030.1 ◽

2019 ◽

Vol 32 (20) ◽

pp. 6899-6915 ◽

Cited By ~ 6

Author(s):

A. Gossart ◽

S. Helsen ◽

J. T. M. Lenaerts ◽

S. Vanden Broucke ◽

N. P. M. van Lipzig ◽

...

Keyword(s):

Relative Humidity ◽

Surface Temperature ◽

Mass Balance ◽

Ice Sheet ◽

Surface Mass Balance ◽

Antarctic Ice Sheet ◽

Near Surface ◽

Surface Mass ◽

Atmospheric Rivers ◽

The Antarctic

Abstract In this study, we evaluate output of near-surface atmospheric variables over the Antarctic Ice Sheet from four reanalyses: the new European Centre for Medium-Range Weather Forecasts ERA-5 and its predecessor ERA-Interim, the Climate Forecast System Reanalysis (CFSR), and the Modern-Era Retrospective Analysis for Research and Applications, version 2 (MERRA-2). The near-surface temperature, wind speed, and relative humidity are compared with datasets of in situ observations, together with an assessment of the simulated surface mass balance (approximated by precipitation minus evaporation). No reanalysis clearly stands out as the best performing for all areas, seasons, and variables, and each of the reanalyses displays different biases. CFSR strongly overestimates the relative humidity during all seasons whereas ERA-5 and MERRA-2 (and, to a lesser extent, ERA-Interim) strongly underestimate relative humidity during winter. ERA-5 captures the seasonal cycle of near-surface temperature best and shows the smallest bias relative to the observations. The other reanalyses show a general temperature underestimation during the winter months in the Antarctic interior and overestimation in the coastal areas. All reanalyses underestimate the mean near-surface winds in the interior (except MERRA-2) and along the coast during the entire year. The winds at the Antarctic Peninsula are overestimated by all reanalyses except MERRA-2. All models are able to capture snowfall patterns related to atmospheric rivers, with varying accuracy. Accumulation is best represented by ERA-5, although it underestimates observed surface mass balance and there is some variability in the accumulation over the different elevation classes, for all reanalyses.

Download Full-text

Surface and snowdrift sublimation at Princess Elisabeth station, East Antarctica

The Cryosphere ◽

10.5194/tc-6-841-2012 ◽

2012 ◽

Vol 6 (4) ◽

pp. 841-857 ◽

Cited By ~ 24

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.

Download Full-text

Brief communication: Impact of common ice mask in surface mass balance estimates over the Antarctic ice sheet

10.5194/tc-2021-317 ◽

2021 ◽

Author(s):

Nicolaj Hansen ◽

Sebastian Bjerregaard Simonsen ◽

Fredrik Boberg ◽

Christoph Kittel ◽

Andrew Orr ◽

...

Keyword(s):

Mass Balance ◽

Climate Models ◽

Regional Climate ◽

Ice Sheet ◽

Regional Climate Models ◽

Surface Mass Balance ◽

Surface Mass ◽

Glacier Ice ◽

High Precipitation ◽

The Antarctic

Abstract. Regional climate models compute ice sheet surface mass balance (SMB) over a mask that defines the area covered by glacier ice, but ice masks have not been harmonised between models. Intercomparison studies of modelled SMB therefore use a common ice mask. The SMB in areas outside the common ice mask, which are typically coastal and high precipitation regions, are discarded. Ice mask differences change integrated SMB by between 40.5 to 140.6 Gt yr−1, (1.8 % to 6.0 % of ensemble mean SMB), equivalent to the entire Antarctic mass imbalance. We conclude there is a pressing need for a common ice mask protocol.

Download Full-text

Surface Mass Balance of the Antarctic Ice Sheet and its link with surface temperature change in model simulations and reconstructions

10.5194/tc-2019-111 ◽

2019 ◽

Cited By ~ 3

Author(s):

Quentin Dalaiden ◽

Hugues Goosse ◽

François Klein ◽

Jan T. M. Lenaerts ◽

Max Holloway ◽

...

Keyword(s):

Surface Temperature ◽

Mass Balance ◽

Regional Scale ◽

Ice Sheet ◽

Surface Mass Balance ◽

Antarctic Ice Sheet ◽

Surface Mass ◽

Model Simulations ◽

Surface Temperatures ◽

The Antarctic

Abstract. Improving our knowledge of the temporal and spatial variability of the Antarctic Ice Sheet (AIS) Surface Mass Balance (SMB) is crucial to reduce the uncertainties of past, present and future Antarctic contributions to sea level rise. Here, we show that Global Climate Models (GCMs) can reproduce the present-day (1979–2005) AIS SMB and the temporal variations over the last two centuries. An examination of the surface temperature–SMB relationship in model simulations demonstrates a strong link between the two. Reconstructions based on ice cores display a weaker relationship, indicating a model-data discrepancy that may be due to model biases or to the non-climatic noise present in the records. We find that, on the regional scale, the modelled temperature-SMB relationship is stronger than the relationship between δ18O-temperature. This suggests that SMB data can be used to reconstruct past surface temperatures. Using this finding, we assimilate isotope-enabled model SMB and δ18O output with ice-core observations, to generate a new surface temperature reconstruction. Although an independent evaluation of the skill is difficult because of the short observational time series, this new reconstruction outperforms the previous reconstructions for the continental-mean temperature that were based on δ18O alone with a linear correlation coefficient with the observed surface temperatures (1958–2010 CE) of 0.73. The improvement is largest for the East Antarctic region, where the uncertainties are particularly large. Finally, we provide a spatial SMB reconstruction of the AIS over the last two centuries showing 1) large variability in SMB trends at regional scale; and 2) a large SMB increase (0.82 Gt year−2) in West Antarctica over 1957–2000 while at the same time, East Antarctica has experienced a large SMB decrease (−3.3 Gt year−2), which is consistent with a recent reconstruction.

Download Full-text