Towards an Antarctic Rift Catalog (ARC)

Abstract:

Ice shelves exert a net force on the grounded part of marine ice sheets, and thereby act to reduce the ice sheet contribution to global sea level rise. Ice shelf rifts are large, through cutting fractures in ice shelves that jeopardize this stabilizing tendency. In order to understand the nature of ice shelf rift formation and propagation, as well as their eventual role in calving, we present an Antarctic Rift Catalog (ARC) built using ICESat-2. We focus our initial efforts on the Brunt Ice Shelf (BIS), a location chosen because of the ongoing operation of an extensive GPS array. In approximately two and a half years of data collection (i.e., as of Release 3) , ICESat-2 has made 504 passes over the BIS from which we extract 574 unique rift width measurements along a particular rift called the Halloween Crack. Our catalog shows the presence of multiple parallel fractures whereas imagery only indicates the presence of a single large rift, thus suggesting that rifts have more distributed damage than previously thought. The ARC illustrates the transformative observational ability of ICESat-2 for studying ice shelf processes.