Supraglacial Lake Depth Estimation Using ICESat-2 Over Amery and Nansen Ice Shelves, AntarcticaFinal Paper Number: C55A-0573

Abstract

Ice shelves play an important role in Antarctic mass balance by buttressing grounded ice. Supraglacial lakes can threaten the stability of ice shelves through the mechanisms of hydrofracture and flexure. Supraglacial lakes also lower the albedo of the surface which can increase surface melting. Thus, it is important to understand and accurately measure variations in lake characteristics, particularly lake depth. Many studies have used optical satellite imagery such as Landsat and Sentinel-2 to measure lake depth. Since 2018, studies have also used ICESat-2 data to estimate lake depth focusing on Amery Ice Shelf. In this study, we use ICESat-2 over the Amery and Nansen Ice Shelves in East Antarctica and develop a new approach to estimate lake depth. We examine the ATL03 product, which is the sole source of the photon data used by higher level products of ICESat-2, and bin them into histograms. ATL06, a land ice product, gives the height information for the surface, hence it is used to detect the surface of lakes along with ATL03. The peaks in histogram are observed in areas with surface photons and histogram values smaller than the peak are identified to be lake bottom. We find that histogram values smaller than the peak are only observed in areas where lakes are present, while in other locations where there are no lakes, histograms show a single peak depicting surface heights. We examined the lakes on Amery and Nansen Ice Shelves and found the depth of these lakes to range between 1-5 m. These results are compared with previous studies over Amery Ice Shelf using ICESat-2.