Warm waves in north-western Spitsbergen

In this study, weather conditions causing warm waves in north-western Spitsbergen, exemplified by Ny-Alesund station, were analyzed. Between 1981 and 2010, 536 days with the maximum temperature exceeding 8.3 degrees C (the value of 95 percentile) were selected. 37 warm waves, which altogether lasted 268 days, were identified. A typical feature of pressure pattern causing warm waves was the appearance of positive anomalies of both the sea level pressure and the height of isobaric surface 500 hPa in the Euro-Atlantic sector of the Arctic. This indicates a presence of high-pressure systems in this region. Extremely warm days appeared more often with the circulation from the eastern than the western sector. Longer and warmer heat waves occurring in the last decade of the analyzed period may be considered as a sign of climate warming, which has a significant impact on environment, i.e. reduction in area and thickness of glaciers, reduction of permafrost and snow cover, changes in biodiversity, etc. The increase in the air temperature and more frequent occurrence of heat waves may encourage development of tourism in polar areas, potentially causing further changes in the environment.