Z badań naturalnych i antropogenicznych zmian klimatu Polski

The goal of this research is to define the degree of air temperature deformation caused by cities in Poland (Stopa-Boryczka M., Boryczka J. and others 1995). At first the geographical position influence on European cities thermic features estimation was made - taking Poland into particular consideration. Statistic models of big areas (Europe) and of medium areas (Poland) show natural factors predomination in shaping the climate in cities: latitude (conditioning climatal zonality), distance from the Atlantic Ocean (warming influence of maritime- polar air-masses in winter) and height above sea-level. The particular research on anthropogenic factors influence on local climate has been conducted on the example of Warsaw. Thermal energy surplus quantitative indicator in Warsaw constitutes higher air temperature in the city, than in its surroundings. This is so called urban heat island. This phenomenon is unstable and it shows a great variability in daily cycle as well as in annual cycle - depending on atmosphere condition. In Warsaw the urban heat island shows even a time - many years' - trend. The biggest beat resources in Warsaw can by found during summer night. In July the minimum temperature differences are over 1.7°C, and in January only 0.5°C. In summer time in Warsaw, the mean daily temperature is 0.7°C higher than that of Warsaw surroundings. The Warsaw urban heat island depends on atmosphere condition - air temperature, cloudiness and wind speed. The biggest difference in air temperature (9.1ºC) has been noted on days the 30th of July and on the 17th of August 1992, within anticyclonic type of South-Eastern circulation. Contrast between urban and its surroundings temperatures becomes more intensive particularly during cool fronts in night time and late evening hours.