Large sea ice outflow into the Nares Strait in 2007

Abstract

Sea ice flux through the Nares Strait is most active during the fall and early winter, ceases in mid‐ to late‐winter after the formation of ice arches along the strait, and re‐commences after breakup in summer. In 2007, ice arches failed to form. This resulted in the highest outflow of Arctic sea ice in the 13‐year record between 1997 and 2009. The 2007 area and volume outflows of 87 × 103 km2 and 254 km3 are more than twice their 13‐year means. This contributes to the recent loss of the thick, multiyear Arctic sea ice and represents ∼10% of our estimates of the mean ice export at Fram Strait. Clearly, the ice arches control Arctic sea ice outflow. The duration of unobstructed flow explains more than 84% of the variance in the annual area flux. In our record, seasonal stoppages are always associated with the formation of an arch near the same location in the southern Kane Basin. Additionally, close to half the time another ice arch forms just north of Robeson Channel prior to the formation of the Kane Basin arch. Here, we examine the ice export with satellite‐derived thickness data and the timing of the formation of these ice arches.