Abstract. The Antarctic continent is a vast desert and is the coldest and the most
unknown area on Earth. It contains the Antarctic ice sheet, the largest
continental water reservoir on Earth that could be affected by the current
global warming, leading to sea level rise. The only significant supply of ice
is through precipitation, which can be observed from the surface and from
space. Remote-sensing observations of the coastal regions and the inner
continent using CloudSat radar give an estimated rate of snowfall but with
uncertainties twice as large as each single measured value, whereas climate
models give a range from half to twice the space–time-averaged observations.
The aim of this study is the evaluation of the vertical precipitation rate
profiles of CloudSat radar by comparison with two surface-based micro-rain
radars (MRRs), located at the coastal French Dumont d'Urville station and at
the Belgian Princess Elisabeth station located in the Dronning Maud Land
escarpment zone. This in turn leads to a better understanding and
reassessment of CloudSat uncertainties. We compared a total of four
precipitation events, two per station, when CloudSat overpassed within 10 km
of the station and we compared these two different datasets at each vertical
level. The correlation between both datasets is near-perfect, even though
climatic and geographic conditions are different for the two stations. Using
different CloudSat and MRR vertical levels, we obtain 10 km space-scale and
short-timescale (a few seconds) CloudSat uncertainties from −13 % up to
+22 %. This confirms the robustness of the CloudSat retrievals of snowfall
over Antarctica above the blind zone and justifies further analyses of this
dataset.
Abstract. The Antarctic continent is a vast desert, the coldest and the most unknown area on Earth. It contains the Antarctic ice sheet, the largest continental water reservoir on Earth that could be affected by the current global warming, leading to sea level rise. The only significant supply of ice is through precipitation, which can be observed from the surface and from space. Remote sensing observations of the coastal regions and the inner continent using CloudSat radar give an estimated rate of snowfall but with uncertainties twice as large as each single measured value, whereas climate models give a range from half to twice the time and spatial average observations. The aim of this study is the evaluation of the vertical precipitation rate profiles of CloudSat radar by comparison with two surface-based Micro-Rain Radars (MRR), located at the coastal French Dumont d'Urville station and at the Belgian Princess Elisabeth station, located in the Dronning Maud Land escarpment zone, respectively. This in turn leads to a better understanding and reassessment of CloudSat uncertainties. We compared a total of four precipitation events, two per station, when CloudSat overpassed within 10 km of the stations and we compared these two different data sets at each vertical level. The correlation between both datasets is near-perfect, even though climatic and geographic conditions are different for the stations. Using different CloudSat and MRR vertical levels, we obtain 10km-space and seconds-short-time CloudSat uncertainties from −24 % up to +21 %. This confirms the robustness of the CloudSat retrievals of snowfall over Antarctica above the blind zone and justifies further analyses of this dataset.
The ice sheet and glaciers of Antarctica and Greenland represent the largest sources of freshwater on planet Earth. The understanding and quantification of their dynamic properties such as albedo, precipitation, ice mass movement, and ice elevation changes are critical for the improved climate and mass balance models. The present study utilizes space-borne optical and synthetic aperture radar (SAR) imagery to measure the ice surface velocity at high spatial resolution for a part of the central Dronning Maud Land (cDML), East Antarctica. The datasets from Landsat-8 and Sentinel-1 SAR satellite are used for ice stream velocity estimation using feature-offset tracking and differential interferometric SAR (DInSAR) methods. The derived velocity products are validated with ground based stakes network at annual time scale. The fundamental ice flow laws are used to estimate the ice outflux or discharge for selected ice stream drainage basins of cDML at fluxgate locations. The ice stream basin has been delineated using combination of elevation, slope and continental scale velocity maps. The ice influx for study area is estimated using ECMWF fifth generation reanalysis (ERA5) and Regional Atmospheric Climate Model (RACMO) v2.3 model outputs. The estimated influx and outflux are in the ranges of 0.18–4.167 Gt/y and 0.201 to 1.278 Gt/y respectively, indicating net positive mass balance for the selected area.
Antarctic ice sheet
The Antarctic ice sheet is one of the two continental glaciers of the world. It covers 98% of the Antarctic continent, and is the largest single block of ice in the world, with at least 14 million km² and contains 30 million km³ of ice. Maintains more than 90% of Earth's total volume of glacier ice, compares with the 8% that represents the Greenland ice sheet, in the Northern Hemisphere, This ice sheet of Antarctica reaches average of thickness at 4 km, situating the bedrock in some points at 2 km under the sea level.
On many points along the Antarctic coast, the ice sheet continues with larger masses of ice partially floating and tied to land called ice barriers or ice shelves. The largest of these is the Ross Ice Shelf, with an area of 500,000 km² and 50 m of average highness. Said shelves represent fractions of the ice sheet pushed to the sea. The Antarctic ice sheet moves from the outer to a estimated cup beetwen 25 and 100 meters by year, being able to reach 1000 meters per year or more in the case of the ice shelves of the coasts. Its age is 33,6 million years.
Greenland contains the second largest ice sheet on the planet, after Antarctica. The ice thicknesses reach up to 3 a.m. 0 metres. The casting of all island ice would led to a six-meter sea level rise. In addition, the release of the ice would cause an ascent of the Greenland plate with tectonic movements. NASA has drawn up a 3D ice map to learn about its origin and training throught the ‘Icebridge\’ project.
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