Spatio-temporal Characterisation of Observed SCATSAT-1 Radar Cross Section on the Snow and Ice Surface of Greenland

Greenland ice sheet has the potential to exert a notable impact on the rise of sea level in the background of global warming. Microwave Remote sensing observations, due to their synoptic and all-weather capability, have been preferred to study the snow melt/freeze condition of the cryosphere. In the current study, near-surface melt characteristics of the Greenland ice sheets were analysed using ISRO’s SCATSAT-1 RADAR Cross Section (RCS) observations in conjunction with ERA5 near the surface temperature at a daily scale for 2017–2020. RCS of HH and VV polarization shows similar spatial variability and sensitivity across Greenland. PDFs are similar for both the polarizations with multi- modal distribution of RCS, which signify the mixing of two or more classes of snow conditions. Mean climatology indicates the existence of 2 distinct regions: central high altitude-plateau (> 2500 m) characterized by lower mean RCS with small seasonal amplitude (< 0.5) considered as the permanent snow/ice cover region and the peripheral region (altitude < 2500 m) characterized by higher mean RCS and higher seasonal amplitude (0.5–2) as the dynamic region. Greenland was divided into 6 major classes based on the climatological mean of RCS in association with topography, and each class is characterized with a unique unimodal PDF. Analysis using RCS and temperature was carried out for melt/freeze identification and quantification of temporal dynamics of snow melt regions for each class. The melt prone regions of Greenland had an early melt onset and delayed freeze onset by almost 15 days in 2019, when compared to other years. During the peak melt period, Greenland had an excess melt of approximately 26% in 2019 when compared to 3-year average of 2017–2020 (excluding 2019). A notable 63% of the total Greenland area was in melt condition in 2019 in comparison with an average of 37% during 2017–2020.