Supraglacial Lake Depth Estimation Using ICESat-2 Over Amery and Nansen
Ice Shelves, Antarctica Final Paper Number: C55A-0573
- Mansi Joshi,
- Alberto M Mestas-Nunez,
- Grant J Macdonald,
- Alfonso Fernández
Alberto M Mestas-Nunez
University of Texas at San Antonio
Author ProfileAbstract
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.