Changes of air temperature and precipitation in Poland in the period 1951–2000 and their relationship to atmospheric circulation

An analysis of trends of mean monthly temperature and precipitation totals in Poland in the period 1951–2000 was carried out. Areal means of temperature and precipitation were used, averaged for 51 meteorological stations evenly distributed within Poland's borders. Sensitivity of air temperature and precipitation variations towards circulation was assessed. Circulation variations were expressed by sea‐level pressure in the 52.5°N, 20°E grid point and geostrophic wind calculated from meridional (45–60°N) and latitudinal (10–30°E) pressure gradients. It was shown that the circulation factor explains up to 77% and 44% of temperature and precipitation variance respectively. Significant upward trends of temperature in March and May were detected. Also, the precipitation total in March was on the increase. The last decade of the 20th century was slightly ‘too warm’ in comparison with the circulation‐induced temperature level, as well as with the temperature change scenario according to HadCM2 GS model. An attempt was made to evaluate the contribution of the frequency of snow cover occurrence to the temperature increase in winter, i.e. the temperature–albedo feedback.