Changes in the Bering Sea region: atmosphere—ice—water system in the second half of the twentieth century

We examine the long-range variability in the oceanographic regime of the Bering Sea during the second half of the twentieth century using the largest T-S data set available, containing about 58,000 stations. We focus on changes in the ice-regime and atmospheric processes over the Bering Sea and Western Arctic. Significant differences in the physical state of the Bering Sea were found between a group of anomalous ‘cold’ (1955, 1964, 1971, 1972, 1975, 1976, 1977, 1984, 1988) years and ‘warm’ (1958, 1959, 1962, 1963, 1967, 1978, 1981, 1982, 1987) years. The time-spatial EOF-analyses (product of the first components) show a general cooling in the Bering Sea in 1953–1977 and 1978–1993, and a strong ‘warming’ in 1977–1978. Likewise, the spatial distribution of EOF temperature (2–4 components) indicates opposite thermal states in the western and eastern part of the Bering Sea: if it becomes warmer in the eastern sector, it becomes cooler in the western. Interaction between the Aleutian Low and Siberian High determines the change over the Bering Sea Region.