SEA ICE DISTRIBUTION IN THE BARENTS SEA

This paper provides a statistical description of the sea ice occurrence in the Barents Sea, using yearly maximum sea ice data for the last 36 years from the European Centre for Medium-Range Weather Forecasts (ECMWF). A set of four distribution functions have been estimated with the maximum likelihood method. The distribution functions used were Extreme Value distribution, Gumbel distribution, Normal distribution and kernel density estimation. The normal distribution was found to fit the data best and provide the most likely result. Our results verify dependency of the North Atlantic current on the sea ice edge. Warm water northwards prevents the ice from extending south; this makes the extreme value distribution unlikely since this will prevent long tailed distributions. The results for sea ice occurrence are compared to the boundaries given in the proposed revision to NORSOK N-003. These boundaries were found to be too simplistic and not necessarily conservative. Here we have proposed new and more accurate boundaries for the sea ice occurrence. We have found trends indicating northwards movement of the sea ice edge in the Norwegian Sea and eastern parts of the Barents Sea. These trends are mostly due to less ice in the last ten years and not trends for the whole period. In the south-western parts of the Barents Sea where oil and gas operations are imminent no trends have been discovered. The lack of trend is related to the islands in the western Barents Sea.