Recent changes in sea ice area flux through the Beaufort Sea during the summer

Abstract

AbstractOver the annual cycle, sea ice is sequestered from the Canadian Basin and transported through the Beaufort Sea toward the Chukchi Sea. In recent years, the Beaufort Sea has experienced considerable ice loss during the summer, which may be indicative of recent changes to this process. In order to investigate this, we quantify the sea ice area flux using RADARSAT from 1997 to 2014 at three gates in Beaufort Sea: the Canadian Basin (entrance), mid‐Beaufort (midpoint), and Chukchi (exit). There was a mean annual flux of 42 ± 56 × 103 km2 at the Canadian Basin gate, 94 ± 92 × 103 km2 at the mid‐Beaufort gate and −83 ± 68 × 103 km2 at the Chukchi gate (positive and negative flux signs correspond to ice inflow and outflow, respectively). The majority of ice transport in Beaufort Sea was found to occur from October to May providing replenishment for ice lost during the summer months. The cross‐strait gradient in sea level pressure explains ∼40% of the variance in the ice area flux at the gates. Remarkably, the mean July–October net sea ice area flux at the Chukchi gate decreased by ∼80% from 2008 to 2014 relative to 1997–2007 and became virtually ice‐free every year since 2008. This reduction was associated with younger (thinner) ice that was unable to survive the summer melt season when either being sequestered from the Canadian Basin and transported through Beaufort Sea during the melt season (2008–2011) or remaining immobile and present in the vicinity of the Chukchi gate during the melt season (2012–2014).