Climatic water balance in Poland – intraannual variability and longterm trends

On the basis of data from the period 1966-2020 from about 50 stations in Poland the precipitation and potential evaporation indices will be estimated and their variability analyzed. Different formulas of potential evapotranspiration, based on air temperature, relative humidity, saturation deficit, wind speed and/or sunshine duration, will be compared. Climatic water balance defined as a difference of precipitation and potential evapotranspiration will be calculated and its intraannual variability analyzed. Long-term changes of all three parameters (precipitation, evapotranspiration and climatic water balance) in the context of contemporary warming will be examined. On this basis, the problem of water availability in various regions of the country will be discussed, especially in the context of changes in the spatial distribution and duration of the snow cover.