2002 ARCSS All-Hands Workshop

Mass Balance and Area Changes of four High Arctic Plateau Ice Caps, 1959–2001

Carsten Braun¹, Douglas R. Hardy², Raymond S. Bradley^3
1Department of Geosciences, University of Massachusetts, Morrill Science Center, Campus Box 35820, Amherst, MA, 01003-5820, USA, Phone 413-545-0659, Fax 413-545-1200, carsten@geo.umass.edu
²Department of Geosciences, University of Massachusetts, Morrill Science Center, Campus Box 35820, Amherst, MA, 01003-5820, USA, Phone 802/649-1829, Fax 413/545-1200, dhardy@geo.umass.edu
³Department of Geosciences, University of Massachusetts, Morrill Science Center, Campus Box 35820, Amherst, MA, 01003-5820, USA, Phone 413/545-2120, Fax 413/545-1200, rbradley@geo.umass.edu

Small, stagnant ice caps without appreciable iceflow are particularly sensitive to climatic fluctuations, especially with regard to changes in ablation season temperature, and hence may provide an early warning of climate shifts. In a general sense, the areal extent of such ice caps is strongly related to their annual mass balance. We conducted mass balance measurements and GPS surveys on four High Arctic plateau ice caps from 1999–2001, and compared these measurements with topographic maps and aerial photography from 1959 and previously published data. Murray Ice Cap has experienced negative mass balance for at least the past three years (1999–2001), with net balance (bn) ranging from -0.19 to -0.7 m (1999), -0.12 to -0.87 m (2000), and -0.22 to -0.96 m water equivalent (2001). The mass balance of nearby Simmons Ice Cap was also negative in 2000 (bn = -0.15 to -0.72 m w.e.) and 2001 (bn = -0.37 to -0.7 m w.e.). All four ice caps showed considerable marginal recession and area reduction between 30 and 47 percent since 1959. Overall, the ice caps have experienced considerable mass loss since 1959, except for a period between the mid-1960s to mid-1970s. The regional ELA appears to have risen, on average, above the summits of the ice caps, indicating that the ice caps are remnants of former climatic conditions and out-of-equilibrium with modern climate.

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