Estimation of surface melt induced melt pond depths over Amery Ice Shelf, East Antarctica using Multispectral and ICESat-2 data

Abstract

Surface melting is increasing over the Antarctica continent, with unknown impacts on glacier and ice sheet dynamics at the ice-bed interface. Surface meltwater drains to the bed of Antarctica ice sheets and outlet glaciers, causing accelerations in ice flow (up to 100% greater than the annual mean). Because melt occurrences are currently erratic (also Antarctica surface melt refreezes), effective subglacial drainage cannot be maintained, resulting in repeated short-lived ice flow disturbances and calving of ice shelves. Longterm exposure to strong surface melting promotes the formation of melt ponds and subsequently Supraglacial lakes and therefore there is possibility of hydrofracturing. The present study aims to estimate the volume of surface melt-induced melt ponds over the Amery Ice Shelf (AIS) using a physically-based radiative transfer model. The AIS, located on Antarctica's east coast, is one of the world's biggest glacier drainage basins. The ICESat-2 geolocated photon data were used to validate the depth estimates of melt ponds derived from Landsat-8 and Sentinel-2 multispectral datasets based on the model. The average depth estimated is around 1.9±0.6 m for the melt ponds adopted for the present study. The present study aims to quantify surface melt over the Antarctica continent (AIS region) in the context of India’s scientific credentials in polar science. We recommend monitoring extensive surface melt and subsurface refreezing which might result in more ponding above impermeable ice layers in the coming years.