| Summary: | Badania zostały przeprowadzone w ramach projektu badawczego nr N N306 047939 finansowanego przez Ministerstwo Nauki i Szkolnictwa Wyższego — Narodowe Centrum Nauki The aim of this study was to determine the temporal and spatial variability of strong and very strong highs in an area of the Euro-Atlantic sector limited by the coordinates 20°N—85°N and 50°W—75°E. The research was based on a rich set of data including, at its core, the average daily air pressure values at sea level at 1377 grid points of a 2.5° × 2.5° grid derived from NCEP/NCAR reanalyses. That data set was supplemented by the values of the 500 hPa isobaric level’s height at the grid points mentioned above. Additionally, a wide range of synoptic maps for different pressure surfaces was used. The study covers the period 1951—2010. The significant spatial and temporal variability of the air pressure over Europe and the Atlantic required the finding of a suitable method to identify strong or very strong anticyclonic systems. The results obtained during this study suggest that defining criteria are highly dependent on both the geographical location and the season of the year. Finally, it was assumed that a pressure system would qualify as a strong high if its pressure was equal or higher than 1030 hPa and as a very strong high if the pressure was at least 1035 hPa. The annual course of the number of days meeting a given criterion became the basis for the division of the Euro-Atlantic region into four main anticyclonic regions of the Euro-Atlantic sector and a number of subregions. The most characteristic differences between regions involved pressure values in strong and very strong highs, their annual patterns and long-term variability of the number of days with strong and very strong highs. The highest pressure values were found in regions featuring the strongest continental highs (more than 1060 hPa) and the lowest values in areas of the most active cyclonicity, i.e. the Iceland region (IIIA) and the Southern region (IV). The Azores High region ...
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