Empiryczne modele zmienności klimatu Polski

The aim of the study reported was to identify the characteristic features and the singularities of climate in Poland, resulting from its geographical location in the moderate latitudes of Central Europe. Approximation of the field of air temperature and humidity, cloudiness and precipitation, as well as wind velocity (averages for the years 1951-1960, 1951-1980) was obtained with the help of equations of hyperplanes of regression. In modelling of air temperature regression polynomials of the fourth order with respect to three location coordinates: latitude, φ, longitude, λ, and elevation above sea level, H, were exceptionally applied as well. Introduction of the absolute elevation H into the polynomials of regression, side by side with the geographical coordinates of latitude and Iongitude, φ and λ, significantly enhanced the precision of models, because air temperature is strongly correlated with the elevation variable. This step constitutes a significant contribution of the Department of Climatology from the University of Warsaw to the perfectioning of the statistical models describing the field of meteorological variables. Polynomials of higher orders with respect to the location coordinates (latitude and longitude as well as elevation above the sea level, φ, λ. and H) proved to be the excellent instrument for the study of climate. In contradistinction to the hyperplanes of regression they do not only describe the main characteristics of the field, but also its regional and local variability. The equation of the regression hyperplane (coefficients of partial regression) is defined by the average latitudinal, longitudinal and hypsometric gradients over the areas considered. On the other hand the regression polynomials of higher orders (e.g. of the fourth order) define the local latitudinal, longitudinal and hypsometric gradients at every point of the area studied. A novelty in terms of climatological literature is constituted by the gradient maps for the three kinds of gradients, elaborated for the first time on the example of Poland. Until now the influence of the polar oceanic and continental air masses was being characterized by the isotherms brought to the sea level, with application of the temperature decrease held constant over time and space, amounting to 0.5°C per 100 meters of altitude (Romer, 1949). The report here summarized presents the isolines of the hypsometric gradients on the area of Poland which change over the period of a year. Of essential practical significance are the horizontal gradients at the real altitudes, determined on the bas is of the approximating functions without the altitude above the sea level. The vectors indicate the directions of increase of air temperature on the territory of Poland. They can be used in the forecasts of geographical distribution of air temperature in Poland. The differences between the measured values of air temperature and the ones calculated from the regression polynomials of the fourth order (i.e. the residuals) have been treated as the measures of local deformation of the field by natural factors (mountain peaks, valleys, water bodies) as well as the anthropogenic ones (large towns).