Densification of Snow on the Ice Sheet of Ellsworth Land and the Southern Antarctic Peninsula

Abstract

Abstract Density-depth curves constructed from seismic travel-time data observed at 25 locations, show a large variation over an essentially isothermal area (T = −22±2.6° C). This is correlated with the wide range of mean annual accumulation values. (A = 20 to 50g./cm.2yr). Quantitative estimates of mean annual accumulation can be obtained from seismic refraction data in this area by the expression A = 23.5+0.049(3500−V 200) where V 200 is the compressional wave velocity (m./sec.) observed at 200 m. from the shot point. The density-depth curves can be used to give estimates of accumulation by the expression: where ρ 40 is the density (g./cm.3) at 40 m. depth. The internal consistency of these methods is indicated by the standard deviation of ±2.9./cm.2 yr. for comparisons of accumulation estimates. The theoretical basis for these results is discussed.