Evidence is presented for a distinct pattern of ocean-atmosphere relationship associated with interdecadal variability in the North Atlantic region. Using a century of surface marine observations it is shown that middle- and high-latitude sea surface temperature (SST) display a long-term fluctuation with negative anomalies before 1920, and during the 1970s and 1980s. Positive SST conditions prevailed from about 1930 to 1960. The pattern of interdecadal SST variability is constructed by subtracting the average field during 15 cold years from that during a similar interval of warm years. The early-century warming and the more recent cooling display a similar spatial pattern. In both cases the pattern is basin scale and largely of one polarity, with maxima in the vicinity of Iceland, in the Labrador Sea, and northeast of Bermuda.The corresponding differences in surface atmospheric conditions are determined by averaging and subtracting, in the same manner, fields of sea level pressure (SLP) and surface winds. The results display a circulation anomaly in the middle of the ocean basin, centered at about 45 degrees N and 35 degrees W. In this midocean area, an anomalous cyclonic circulation prevailed during years with warm SST, and an anticyclonic anomaly dominated during years with cold SST. These circulation anomalies are strongest during the winter months.
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