Light absorbing impurity profiles in snow on sea-ice collected during SIPEX II

Particulate impurities in snow such as dust and soot can absorb sunlight. This is important for snow albedo in the Arctic, but probably not in the Antarctic. Snow was collected in plastic bags through the full depth of the snowpack over first-year sea ice at several locations: one location each on Ice Stations 1, 2, 3, 4, 7, upwind of the ship. The snow was melted and the meltwater filtered. The filters will be analysed for light-absorbing impurities in a laboratory spectrophotometer in Seattle. Samples of size ~1 kg were collected at Ice Station 1. The filters were blank, so at Ice Stations 2 and 3 larger samples of size 2-4 kg were collected. The filters were still blank, so at Ice Stations 4 and 7 larger samples of size ~8 kg were collected; these do show a slight darkening visible by eye. No snow samples were collected at Stations 5 and 6. Local (ship) time is UTC+10; Sun time is UTC+8. Filters are labelled with prefix 'AO' for Antarctic Ocean.This dataset currently contains snow density (except for at one ice station) and volumes of melt water that were filtered. No further analysis has been carried out on these samples at this point, however at a later stage the filters will be analysed for spectral absorption and converted to a mixing ratio of black carbon in the snow.