The features of sea-ice cover, snow distribution and its densification in the central arctic ocean

Abstract

Based on the observation of sea-ice cover and measurement of snow depths and stratigraphy during China’s First North Pole Scientific Expedition, three types of surface topography of sea ice and correspondingly three categories of snow distribution in the central Arctic are classified. It is considered that the classification will help to determine the sites for snow depth measurement, stratigraphy observation and snowpits sampling. The snow cover is slowly accumulated during the long Arctic winter, approximately from September to early May next year, while its ablation shows abrupt from south to north. By the end of August, the snow cover is almost totally removed. The spatial distribution of snow depth is characterized by a northwardly decreasing trend, which is proposed to result from the remote vapour sources, i.e., the major vapour over the Arctic regions is transported from mid-latitudes. The stratigraphy of the snowpits are characterized by the extensively existed depth hoar at the deeper part of the pits, which is probably a signal of the beginning of the long Arctic winter. The present of infiltration-congelation ice adhering to sea ice surface at the end of the ablation season indicates that the annual accumulation is approximately equals to the annual ablation near north pole.