Relations between winter climate and ionic variations in a seven-meter-deep snowpack at Okstindan, Norway

Seven meters of snow accumulated at 1470 m above sea level on the Norwegian glacier Austre Okstindbreen during the 1994-95 winter. Fifty samples, toge ther representing the entire snowpack, were collected in a continuous colum n downwards from the surface on 29 April 1995, before the onset of melting. The water-equivalent thickness of each sample was calculated from density measurements. Concentrations of Na+ and non-sea-salt (nss) SO42- in the sam ples were measured and the ionic loads determined. In an attempt to date so me of the stratigraphic variations of ionic concentrations, use was made of precipitation data from the monitoring site Tustervatn (439 m asl), 25 km southwest of the glacier. Synoptic conditions associated with heavy precipi tation, extended periods of dry weather, high Na+ loading, and high nss SO4 2- loading were identified. Daily values for precipitation amount, Na+ load , and nss SO42- load for the 115 d on which more than 1 mm of precipitation was recorded were recalculated as percentages of the winter totals. Compar ison of data from Tustervatn and the 1470 m site indicates that about 2.5 m of the 1470 m snowpack had accumulated by the end of November 1994, 4 m by the middle of January, and 25 m by mid-February.