Changes in the Norwegian sea levels and the ice conditions of the Kara sea in winter-spring months

Abstract

The conditions of navigation on the Northern Sea Route (hereinafter referred to as the NSR) are largely determined by changes in the average thickness and concentration of the ice cover in its sections. These changes can be caused by different natural processes, a more complete understanding and consideration of which can significantly improve the quality of medium-term forecasts of ice conditions in the Arctic seas. The areas of the NSR with the most intensive shipping are currently located in the Kara Sea, where, despite difficult ice conditions particularly in the winter-spring period, navigation is year-round. The authors put forward a hypothesis that interannual variations in ice thickness and concentration of some sections of the Kara Sea in winter-spring months can be significantly influenced by changes in the Norwegian Sea level. The paper verifies this assumption and provides an assessment of current trends in the Norwegian Sea level variations. The research methodology is based on standard methods of mathematical statistics. GLORYS12v.1 reanalysis is used as a data source. It is shown that a large number of areas for which the hypothesis is true exist in the Kara Sea in certain months. For the same months, an increasing trend in interannual variations in the mean level of the Norwegian Sea is found for the last two decades. Qualitative forecasts of the Kara Sea ice thickness and concentration are provided which will be relevant as long as the Norwegian Sea level dynamics does not change and the identified relationships stay significant.