Impact of River Discharge and Regional Climatology on the Decay of Sea Ice in the Laptev Sea during Spring and Early Summer

Abstract

Summer sea-ice conditions in the Laptev Sea are characterized by high interannual variability. The impact of Lena River discharge, one of the Arctic's major rivers discharging roughly 525 km³ annually onto the Laptev shelf, and the regional meteorological regime affect the spring and summer ice regime of the Laptev Sea. Using ground and remote-sensing data and statistical analyses, it is shown that river discharge plays an insignificant role in the large-scale decay of the Laptev Sea ice cover. Hydrological and remote sensing data for the period 1979–1990 show that discharge/sea-ice interactions are confined to the coastal regions, with Lena River water flooding a fast-ice belt, roughly 25 km wide, in early to mid-June. Sea-ice decay and summer ice extent are shown to be affected most strongly by dynamic atmospheric forcing and by opening and enlargement of coastal polynyas in early spring.