Synoptic Activity in the Arctic Basin, 1979–85

Synoptic activity in the Arctic basin from 70°–907deg;N is examined for the period 1979–85, using improved pressure analyses incorporating data from a network of drifting buoys. Geographical and seasonal variations in cyclone and anticyclone frequencies, mean cyclone pressures and other cyclone characteristics are determined. Results, in general, compare favorably with those from earlier studies. The atmospheric circulation of the Arctic is characterized by strong seasonality, but with considerable year-to-year variability, evidenced through large-scale seasonal shifts in the position and intensity of cyclone and anticyclone frequency maxima, the types of systems comprising these pattern, and major cyclone tracks. In winter and spring, cyclonic activity is largely restricted to the eastern Arctic. Local frequency maxima are found near Svalbard, the northern tip of Novaya Zemlya, and, in winter, also near the Pole at about 90°E. The systems comprising these patterns are migratory, the majority entering store the North Atlantic and Barents Sea. Corresponding anticyclone frequency maxima occur within the Canada basin, in a broad zone from about 160°E to 140°W, extending up to 85°N. By contrast, the Canada basin in summer is the region of highest cyclone frequencies. Systems migrate into this region primarily from along the Siberian coast and subsequently stall, resulting in a persistent persistent of low pressure analogous to the Ieclandic low. This summer cyclone pattern is detailed in a case study. The summer anticyclone pattern consists of four distinct cells at about 78°N from 60°E to 150°W. Autumn is a transitional season, with cyclone frequency patterns similar to summer and winter, and anticyclone patterns similar to winter and spring.