Synoptic and subsynoptic variability in the North Atlantic as revealed by the Ocean Weather Station data

Surface meteorological records from Ocean Weather Stations are used to char acterise interannual changes in the intensity of synoptic and subsynoptic p rocesses over the North Atlantic mid-latitudes during the period from early the 1950s to 1990s. Individual 3-hourly data were filtered to separate ult ra-high frequency variability (0-2 days) and synoptic scale variability (2- 6 days). Joint consideration of the intensities at these 2 scales in mid-la titudes makes it possible to construct parameters which are highly correlat ed with the North Atlantic Oscillation index. In high latitudes, intensitie s of synoptic and ultra-high-frequency processes are strongly negatively co rrelated on interannual and decadal time scales. This phenomenon is discuss ed in the context of interaction between high and mid-latitudinal synoptic variability.