Changes in thermal and precipitation conditions in Poland in 1971–2010

Abstract

Abstract Changes in thermal and precipitation conditions in Poland in 1971-2010. The article presents changes in thermal and precipitation conditions on Polish territory in the years 1971- -2010 based on data from six meteorological stations (Koszalin, Olsztyn, Poznań, Lublin, Opole and Kraków). These data concern the monthly average air temperature, precipitation and the number of days with precipitation per month. Based on the analysis of changing trends in the study of meteorological elements, authors observed an increase in the mean annual air temperature of about 0.9°C over 10 years in all localities. In contrast, trends in the average monthly air temperatures were characterised by temporal and spatial variation. As a result of the increase in temperature, there was a change in the dates signifying the beginning and the end of the thermal periods: farming (OG), vegetation (OW), intensive vegetation (OIW) and maturation or thermal summers (OD/L). A tendency for these periods to start earlier was noted. Statistically significant changes were found for the following periods: vegetation in Koszalin and Olsztyn, intensive vegetation at all stations and thermal summer only in Lublin. An increasingly later end to these periods was noted, and statistically significant trends were found for the dates of the end of the following periods: maturation (thermal summer) at all stations except Opole, intensive vegetation in Poznań and Lublin and vegetation in Lublin and Opole. Seasonal and monthly precipitation totals in the years 1971-2010 were characterised by cyclicality. Significant upward trends were found only in the case of monthly precipitation totals in August in Koszalin and the sum of precipitation in the cooler half of the year in Poznań. In contrast, there was more days with precipitation at all stations included in the study, but the statistical significance of trends varied by location. Changes in thermal and precipitation conditions were accompanied by, among other factors, an increase in temperature, changes in the length of thermal periods and an increase in the frequency of rainfall. All of this is important information for the agricultural sector regarding changing crop conditions