Figure 2.

Temporal and spatial variation of snowmelt in Antarctica ice sheet derived from the SMMR and SSM/I data during 1978–2020. Reddish colors show areas with rates that are greater than zero and are significant at the 95% level, indicating that the onset or end date was delayed, whereas blueish colors indicate that the onset date or end date was significantly advanced. (A) Distribution of the average number of melt days per year on the Antarctic ice sheet during 1978–2020. Distribution of the regions where the trends in snowmelt (B) duration, (C) onset date and (D) end date are significant at the 95% level. 54% of the snowmelt area was shortened in duration by ≥0.1 days per year, while 29% of the snowmelt area extended their duration by >0.1 days per year. 62% (of which 67% have a 95% significant trend) and 52% (of which 57% have a 95% significant trend) of the snowmelt area experienced delays in onset and termination dates by >0.1 days per year, respectively. Distribution of the regions where the trends in snowmelt onset date during (E) 1978–2014 and (F) 2014–20 and end date during (G) 1978–2014 and (H) 2014–20 are significant at the 95% level. The Ross Ice Shelf region was not included in the statistical analysis because of the infrequent snowmelt in these areas.