Krystyna Bryś

Abstract

The Authors present the results of a statistical-climatological study of evapora-tion from the water surface in Wrocław and its variability in the years 1946-1995. The evaporation was characterized by year-to-year variability in the annual, half-year and monthly sums and the multi-year trends were determined mathematically with the help of linear and polynomial trends of the 3rd and 6th degrees. The trends were compared with the long-inter-val tendencies for the basic factors controlling evaporation, i.e. with saturation deficit, solar global radiation and wind velocity. The "variability of variability" was taken into consider-ation and multi-year periods of relative stabilization and extinction of amplitude fluctuations separated and contrasted with intervals of increased fluctuational dynamics. The analysis points to the occurrence of 8, 10-11, 16 and 21-23-year evaporation rhythms. The overall findings were investigated in the context of solar activity (Wolfs number) and of multi-year circulation changes in Poland.

Keywords: evaporation from water surface, Wild's balance-evaporimeter, factors control-ling evaporation, multi-year variability, solar activity, atmospheric circulation

Krystyna Bryś, Department of Agro- and Hydrometeorology, Agricultural University at Wrocław, Plac Grunwaldzki 24, 50-363 Wrocław, Poland
Tadeusz Bryś, Department of Agro- and Hydrometeorology, Agricultural University at Wrocław, Plac Grunwaldzki 24, 50-363 Wrocław, Poland