Evaluation of CloudSat snowfall rate profiles by a comparison with in situ micro-rain radar observations in East Antarctica

Abstract

Abstract. The Antarctic continent is a vast desert and is the coldest and the most\nunknown area on Earth. It contains the Antarctic ice sheet, the largest\ncontinental water reservoir on Earth that could be affected by the current\nglobal warming, leading to sea level rise. The only significant supply of ice\nis through precipitation, which can be observed from the surface and from\nspace. Remote-sensing observations of the coastal regions and the inner\ncontinent using CloudSat radar give an estimated rate of snowfall but with\nuncertainties twice as large as each single measured value, whereas climate\nmodels give a range from half to twice the space–time-averaged observations.\nThe aim of this study is the evaluation of the vertical precipitation rate\nprofiles of CloudSat radar by comparison with two surface-based micro-rain\nradars (MRRs), located at the coastal French Dumont d Urville station and at\nthe Belgian Princess Elisabeth station located in the Dronning Maud Land\nescarpment zone. This in turn leads to a better understanding and\nreassessment of CloudSat uncertainties. We compared a total of four\nprecipitation events, two per station, when CloudSat overpassed within 10\u2009km\nof the station and we compared these two different datasets at each vertical\nlevel. The correlation between both datasets is near-perfect, even though\nclimatic and geographic conditions are different for the two stations. Using\ndifferent CloudSat and MRR vertical levels, we obtain 10\u2009km space-scale and\nshort-timescale (a few seconds) CloudSat uncertainties from −13 \u2009% up to\n +22 \u2009%. This confirms the robustness of the CloudSat retrievals of snowfall\nover Antarctica above the blind zone and justifies further analyses of this\ndataset.