Basal melt rates and mechanical properties of the Ekström Ice Shelf, East Antarctica, inferred from repeat, quad-polarimetric radar data

Ice shelves buttress ice flow from Antarctica’s interior and provide the interface for ice-ocean interactions. Here, we present a comprehensive dataset collected with autonomous phase-sensitive radio-echo sounders (ApRES) on the Ekström Ice Shelf in East Antarctica. The data include a one year time series of basal melt near the grounding zone and > 40 repeat and quad-polarimetric observations covering the entire ice shelf with the transition to grounded ice and multiple lateral shear zones. The inferred melt rates are put into context in terms of their seasonality and with respect to spatial patterns which were mapped in the internal ice stratigraphy. The polarimetric backscatter show signs of anisotropic ice fabric and spatial changes can be traced coherently from the grounding line to the ice-shelf front. We investigate those signatures in conjunction with the vertical strain rates inferred from ApRES and ice-flow modelling to learn more about ice-shelf rheology, particularly with respect to the stress exponent n.