An examination of storm activity in the Northeast Atlantic region over the 1851-2013 period using the EMULATE gridded MSLP data series

The gridded mean sea level pressure (MSLP) series developed by the European and North Atlantic Daily to Multidecadal Climate Variability (EMULATE) project is used in this paper to analyze changes in storm activity in the northeast Atlantic region over the period 1851–2003. Zonal and meridional geostrophic wind speed components were calculated for each grid square over the domain 65°W–45°E, 30°N–65°N, and seasonal percentiles from these data were used as a measure of storm activity in the region. Despite the relatively coarse temporal (daily) and spatial (5° × 5°) resolution of the data, the results indicate that the series are able to provide useful information about storm activity across the northeast Atlantic domain back to 1881 and in the data-rich area of the North Sea back to 1851. The variability of winter storm activity observed across the North Sea over the last 153 years, and particularly the increase to high values in the 1990s, is closely associated with the variability of the North Atlantic storm track. In contrast, high summer values in the late nineteenth century appear to have been related to a Greenland-blocking system, leading to high meridional flow in the region. This latter conclusion is limited, however, by poor data coverage in the northwest Atlantic region.