Recent variations in surface mass balance of the Antarctic Peninsula ice sheet

Over the period 1972-98 the height of the snow surface at eight Antarctic sites in Palmer Land and on Alexander Island has been measured with respect to fixed points on local nunataks. From these data an empirical relation between height changes over a given period and three key variables has been derived. These variables are (i) the local mean annual surface air temperature, (ii) a regional estimate of energy available for melt over the period (derived from the nearby Rothera air-temperature record) and (iii) a regional estimate of accumulation over the period (derived from the nearby Gomez Nunatak ice-core accumulation record). Using this relation, the contribution of the Antarctic Peninsula to sea-level rise for warming from climatic conditions (averaged over the last 30 years) is estimated to be -0.006 +/- 0.002 mm a(-1) K-1. If recent warm conditions persist, however, and meltwater can run off to the sea, the contribution to sea-level rise from ablation is calculated to be 0.07 +/- 0.02 mm a(-1) K-1.