SNOW-ACCUMULATION VARIABILITY FROM SEASONAL SURFACE OBSERVATIONS AND FIRN-CORE STRATIGRAPHY, EASTERN WILKES LAND, ANTARCTICA

Annual accumulation records were derived from two firn cores drilled at GD03 (69-degrees-00' S, 115-degrees-30' E, 1835 m) and GD 15 (69-degrees-00' S, 130-degrees-48' E, 2155 m), which are separated by 750 km along the 2000 m contour in eastern Wilkes Land. The accumulation records, spanning the period 1930-85, show that annual accumulation has increased by 25% from 1960 to 1985, resulting in the highest accumulation rates in the 55 year records. Annual accumulation layers were identified in the firn cores using a firn-stratigraphic model (based on the observed characteristics and variability of the seasonal snow-surface layer) together with seasonal oxygen-isotope ratios. The accumulation records support other evidence for a similar recent increase across Antarctica. The greater increase over the long-term mean for 1930-85 in eastern Wilkes Land was observed at GD 15 which is located on a northeast aspect slope near Terre Adelie. It is suggested that the increase is the result of changes in the general atmospheric circulation pattern which have produced a higher annual frequency of precipitation events.