A comparative analysis between variations in wet snow zone and the main break-up and disintegration events in WILKINS ice shelf, Antarctic peninsula

Abstract

Abstract This study analyses areal extent variations in the Wet Snow Zone (σWSZ) on the Wilkins Ice Shelf (WIS), in the austral summers from of 1978 to 2009. We used data estimated by a linear mixture analysis of SMMR and SSM/I images, in order to calculate the total area of the σWSZ on the WIS. We found that the austral summers of 1982–1983, 1989–1990 and 1997–1998 had the largest σWSZ extents. During 1992–1993, the σWSZ extent was approximately 36,072 km2 (about 45% of the study area), and coincided with a major break-up event along the northern ice shelf edge. A significant break-up in this region also occurred in summer 1998–1999, and was associated with the largest σWSZ extent in the previous summer (45,348 km2). In 2002–2003, the σWSZ extent reached 42,785 km2. In contrast, the 2007–2008 summer did not show a large σWSZ extent (15,889 km2), despite the break-up event in the northern and north-western of WIS in that summer and in the following year. These break-ups have been attributed to basal melting of the WIS in some studies, rather than surface-based hydrofracture, although sub-surface water and hydrofracture was implicated in a study of the 2007–2008 event. The median austral summer σWSZ areal extent has a declining trend of 723 km2 y−1 (r = 0.49), over the period of our study (1978–2009).