WATER-BALANCE ESTIMATES OVER GREECE

Water balance for 31 locations in Greece is calculated on the basis of long-term average monthly precipitation, evapotranspiration and combi ned soil and vegetation characteristics, according to the method propo sed by Thornthwaite and Mather. Monthly evapotranspiration estimates a re calculated from 27 years (1960-1987) of routine meteorological data using the original Penman method. Soil and vegetation characteristics specific for the locations under study are combined in the water capa city of the root zone (WCRZ), Similar water balance calculations were carried out using various fixed values of WCRZ for all stations, to ev aluate the effects of soil and vegetation through the WCRZ in the fina l estimates of soil moisture deficits, Water balance calculations were also performed using average monthly evapotranspiration estimates cal culated according to the empirical Thornthwaite method. Results were c ompared in order to show possible differences that could be attributed to the method of estimating evapotranspiration. Finally, results obta ined with a value of WCRZ fixed at 300 mm and potential evapotranspira tion estimated by the Thornthwaite method for the period 1969-1987 wer e compared with existing similar results over a longer period in the p ast (1931-1968), in order to detect diachronic changes in the water ba lance components over the same regions in Greece.