Changes and surface features of the Larsen Ice Shelf, Antarctica, derived from Landsat and Kosmos mosaics

Abstract

Two uncontrolled mosaics were assembled at an ~1 : 1000 000 scale, covering for the first time almost the entire Larsen Ice Shelf area, using Landsat TM images of 1986-89 and the Kosmos KATE-200 photographic products of late 1975. By comparing them, it was possible to estimate the change along the 600 km north-south ice-shelfs seaward margin where substantial calving has occurred in the recent past. In overall extent, the ice shelf has decreased by ~9300km2 since 1975. The interpretation of the available satellite data also allowed estimates of the ice-shelf’s inland boundary and detection of new surface ice features, especially in the very disturbed region south of Jason Peninsula, which may help to explain the significant calving events occurring in this region. Estimates of surface velocities were derived by photographically co-registering sequential imagery in the chaotic rifted-crevassed area east of Kenyon Peninsula, where conspicuous ice features could be clearly detected even after a 10.4 year time interval. The Landsat TM mosaic, though uncontrolled, provides a basic data set for future studies of global change of the major ice shelf on the Antarctic Peninsula which is probably very sensitive to any climatic trend.

Climatic conditions, mass balance and dynamics of Larsen B ice shelf, Antarctic Peninsula, prior to collapse

“…1) in early 1999. The analysis of available temperature data indicates a high correlation between MST at Marambio and that at Matienzo (Skvarca and others, 1998), allowing us to infer that Larsen B has been subject to an increasing summer warming trend during the past three decades.…”

“…The retreat and disintegration of ice shelves around the Antarctic Peninsula has been described elsewhere (Skvarca, 1994; Rott and others, 1996, 1998; Vaughan and Doake, 1996; Lucchitta and Rosanova, 1998; Skvarca and others, 1999a; Rack, 2000; Scambos and others, 2000, 2003; Skvarca and De Angelis, 2003). The causes of disintegration have been mostly associated with the increasing atmospheric warming and the production of surface meltwater, which plays a fundamental role in fracturing and rifting processes (Weertman, 1973; Scambos and others, 2000, 2003).…”

“…Since Mercer’s (1978) hypothesis that ice shelves fringing the Antarctic Peninsula would start disintegrating as atmospheric warming increased, both an increase in warming trend and the demise of ice shelves in this region have been widely reported (Doake and Vaughan, 1991; King, 1994; Rott and others, 1996; Vaughan and Doake, 1996; Skvarca and others, 1998, 1999b).…”

The motion field of northern Larsen Ice Shelf, Antarctic Peninsula, derived from satellite imagery

“…In the heavily crevassed shear zone between the ice rise (IR) and Bull Nunatak the fringe pattern is discontinuous, which is an indication of rifting described by Skvarca (1994). This rift will be relevant for a possible future disintegration process.…”

Interferometric analysis of the deformation pattern of the northern Larsen Ice Shelf, Antarctic Peninsula, compared to field measurements and numerical modeling

“…The ice shelves of the Antarctic Peninsula are close to the climatic limit for the existence of ice shelves (Mercer, 1978). Significant atmospheric warming, observed on both sides of the peninsula during recent decades (Vaughan and Doake, 1996; Skvarca and others, 1998), has been accompanied by a gradual retreat of ice shelves (Skvarca, 1994). On the eastern side, this retreat culminated in the collapse of the sections of the Larsen Ice Shelf north of Seal Nunataks (Fig.…”