Cyrkulacyjne warunki występowania ekstremalnych opadów atmosferycznych na Spitsbergenie

Abstract

Circulation conditions of extreme precipitation at Spitsbergen were analyzed in this study at the basis of daily data from 1981-2010 from the Svalbard Lufthavn station. The mean annual precipitation in Svalbard Lufthavn amounts to 189.1 mm. The most of extreme daily precipitation cases appear in autumn and winter. It is related to high frequency of deep polar cyclones in the cold part of the year, which bring snow and rain to the Svalbard Archipelago. The highest daily precipitation at Spitsbergen is observed during cyclonal circulation from south-western or western direction. In summer and autumn abundant precipitation is caused by local cyclones appearing right over or northwest to the island. In winter and spring the pressure pattern typical for the days with abundant precipitation characterizes with a thorough of low pressure spreading from the Icelandic Low through the Fram Strait to the Arctic. These circulation patterns are usually accompanied with higher-than-normal pressure over Scandinavia and northern Europe and high pressure gradients over the North Atlantic.