Instruments and methods - Snow density for measuring surface mass balance using the stake method

A measure of snow density is required to estimate water equivalent ice-sheet surface mass balance (SMB) from stake measurements. Previous studies have utilized the snow density at different depths within the snow. By considering the snow densification process in the time interval between stake height measurements, we find that use of the snow density at the base of the stake is more appropriate. We assume the stakes are firmly anchored at the bottom and that Sorge's law holds, i.e. the density-depth profile does not change with time. Applying this method to the data for 36 snow stakes on Dome Fuji, the SMB in 2003 was 36.5 kg m(-2) a(-1), 27% larger than the previous estimate, which used surface snow density. Correct selection of the snow density for SMB estimations is important, especially for Antarctic inland areas where accumulation is low (e.g. Dome Fuji, Vostok, Dome C and South Pole) and where the snow density near the surface varies markedly.