Outflow of Summertime Arctic Sea Ice Observed by Ice Drifting Buoys and Its Linkage with Ice Reduction and Atmospheric Circulation Patterns

Abstract

Drifting buoys deployed near the North Pole in the 2000s revealed that sea-ice export from the Arctic Ocean through the Fram Strait was large in 2005. The relationship between ice drift and sea-level pressure (SLP) showed that the mean SLP from June to September is conducive to continuous sea-ice drift offshore from Siberia. A record minimum of the ice extent in 2005 is partly explained by the strongest SLP gradient across the Transpolar Drift Stream for the recent 27 years from 1979. The SLP pattern regressed on the linear trends of ice extent is characterized by cyclonic circulation anomalies along the Eurasian coast, which tend to enhance the SLP gradient across the Transpolar Drift Stream. The large export of freshwater and sea ice in 2005 could increase the salinity of the upper ocean and lead to development of the mixed layer and suppression of sea-ice growth during the subsequent winter.