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

Abstract

Surface meteorological records from Ocean Weather Stations are used to characterise interannualchanges in the intensity of synoptic and subsynoptic processes over the North Atlanticmid-latitudes during the period from early the 1950s to 1990s. Individual 3-hourly data werefiltered to separate ultra-high frequency variability (0–2 days) and synoptic scale variability(2–6 days). Joint consideration of the intensities at these 2 scales in mid-latitudes makes itpossible to construct parameters which are highly correlated with the North Atlantic Oscillationindex. In high latitudes, intensities of synoptic and ultra-high-frequency processes are stronglynegatively correlated on interannual and decadal time scales. This phenomenon is discussed inthe context of interaction between high and mid-latitudinal synoptic variability.