Variability and Trends of the Summer Melt Period of Antarctic Ice Margins since 1980 from Microwave Sensors

Abstract

The density and range of observations made by meteorological stations is insufficient to fully characterize decadal climate variability in Antarctica. Satellite-borne instruments, which offer a high spatial and temporal density of information, can contribute complementary data for characterizing Antarctic climate change. Here, partial melting of Antarctic snow, which significantly affects the microwave emissivity of the surface, is identified and counted over 18 yr in the 20-yr period 1980?99. The cumulated product of the surface area affected by melting and the duration of the melting event, called cumulative melting surface (CMS), is one of the three melt indices defined and discussed here. On average over the last 20 yr, the Antarctic CMS has decreased by 1.8% ± 1% yr?1, a result that is consistent with a mean January cooling of the continent recently identified from infrared satellite data. In addition, the interannual signatures of the Antarctic Oscillation, and possibly of the Southern Oscillation, are found in the melt indices.