UC San Diego

Amery Ice Shelf (AIS) in East Antarctica acts as the primary buttress for the largest reservoir of potential sea level rise in the region: the Lambert-Amery Basin. Iceberg calving is an important mass loss process for ice shelf systems and is one of the ways that an ice shelf loses mass. While calving events themselves are not inherently concerning for an ice shelf, changes from the steady state such as increased rifting and shortening calving cycles can indicate a mass imbalance. Therefore, it is crucial to understand calving processes to improve our ability to detect potential imbalances. Rifting is a precursor to all tabular iceberg calving events, yet there are many aspects of this process that remain unclear; for example, the disputed role of mélange (the ice mixture which congeals inside the rift at sea level) in rift propagation (Fricker, Young, et al., 2005; Larour et al., 2004). We use advances in satellite remote sensing to develop a metric for characterizing the propagation regime of ice rifts to indicate increased potential for calving events: the Rift Growth Metric (RGM). We determine the RGM from geometric observations derived from Landsat 8 imagery and ICESat-2 laser altimetry. ICESat-2 data enables us to characterize the status and behavior of mélange within each rift investigating its impacts on propagation of ice rifts on AIS. This method determines propagation shifts and assess mélange thickness spatiotemporally using geographic information systems software builds on established behavior of rift system dynamics before and after iceberg calving.