Snow depth product over Antarctic sea ice from 2002 to 2020 using multisource passive microwave radiometers

Abstract. Snow over sea ice controls energy budgets and affects growth melting thus has essential effects on the climate. Passive microwave radiometers can be used for basin-scale snow depth estimation at a daily scale; however, previously published methods applied to Antarctic clearly underestimated depth, limiting their further application. Here, we estimated using passive newly constructed, robust method by incorporating lower frequencies, which have been available from AMSR-E AMSR-2 since 2002. A regression analysis 7 years of Operation IceBridge (OIB) airborne measurements showed that gradient ratio (GR) calculated brightness temperatures in vertically polarized 37 GHz, i.e. GR(37/7), was optimal deriving with correlation coefficient −0.64. We hence derived new coefficients based GR(37/7) improve current radiometers. Comparing retrieval situ Australian Data Centre this outperformed (i.e. linear model GR(37/19)), mean difference 5.64 cm an RMSD 13.79 cm, compared values −14.47 19.49 respectively. comparison shipborne observations Sea Ice Processes Climate indicated thin-ice regions, proposed performed slightly better than previous (with RMSDs 16.85 17.61 respectively). generated complete product 2002 2020 scale, negative trends could found all sectors seasons. This dataset (including both uncertainty) downloaded National Tibetan Plateau Center, Institute Research, Chinese Academy Sciences http://data.tpdc.ac.cn/en/disallow/61ea8177-7177-4507-aeeb-0c7b653d6fc3/ (last access: February 2022) (Shen Ke, 2021, https://doi.org/10.11888/Snow.tpdc.271653).