Tendencies in Climate Changes in Poland and Ukraine During the Last Centuries and Their Causes

The paper describes tendencies in changes of air temperature in Poland and Ukraine on the basis of a long series of measurements made in Warsaw (1779–2000), Cracow (1826–2000), Lviv (1824–2002) and Kiev (1812–2002). Air temperature in these cities in the years 1825–2002 is positively correlated with the North Atlantic Oscillation (NAO) Index. Values of the r correlation coefficient are much higher in winter months than during the summer and they decrease with distance from the Atlantic Ocean. Of interest are air temperature changes in Warsaw, Cracow, Lviv and Kiev in the XIX^th –XX^th centuries together with forecasts until the year 2100. Significant dependence of the climate of Poland and Ukraine on the NAO index stems from similar temperature cycles and the eight-year, eleven-year and one-hundred-year NAO index. Forecast credibility results from the similar periodicity of air temperature, the NAO index and solar activity. The forecast mean annual temperature values for 2001–2100 were obtained from the interference of statistically important temperature cycles, determined by the sinusoidal regression method.