Sea ice drift and area flux in the Fram Strait

By K. Kloster, S. Sandven and J. Wåhlin, NERSC

Synthetic Aperture Radar (SAR) images have been used to estimate ice drift and ice area flux through the Fram Strait for the period 2004 – 2008. SAR Wideswath images from ENVISAT have been collected approximately every three days and ice drift has been retrieved across the strait at 79 N. The monthly area fluxes are presented in Fig. 1 showing a strong seasonal cycle with maximum in winter and minimum summer. The data shows strong year-to-year variability and also an interesting increase in area flux during the last four winter seasons. The mean annual ice velocity as well as area flux for the whole year (01 August – 31 July) are presented in Fig. 2.

Figure 1. Monthly ice area flux across 79°N in the Fram Strait based on SAR data from February 2004 to December 2008. Unit for ice area flux is km2 per month.

 

Figure 2. Annual areal ice flux (blue bars) and average southward ice drift (red curve) at 79N for the last four years based on SAR derived ice drift.

 

The increasing ice area flux in the last four years is interesting to compare with the reduction in ice area in the Arctic Basin. Ongoing studies compare ice drift from several types of satellite data and buoy data. The ice drift data are also used to validate ice-ocean models in the Fram Strait. The work has been supported by the EU projects MERSEA and DAMOCLES as well as the IPY project no. 379: Operational Oceanography for the Arctic Ocean and adjacent seas (Arctic ROOS). The SAR data have been provided by ESA under the IPY AO projects no. 4081 and 4093.