Abstract:

Based on the data of pan evaporation at Changwu Agro-ecological Station (CWA) and meteorological factors during 2007-2015, the dominant factors affecting pan evaporation were analyzed at different time scales using the methods of grey correlation and principal component analysis. Results showed that temperature, vapor pressure, air pressure and sunshine duration were main factors influencing pan evaporation at annual time scale. At   seasonal scale, moreover, the sunshine duration and temperature were dominant factors in spring, for summer, they were temperature and air pressure, and for autumn and winter, they were sunshine duration and vapor pressure, respectively. Temperature, sunshine duration and air pressure were dominant factors which affected pan evaporation at monthly scale. Based on the principal component analysis and the multiple linear regression analysis, a formula was established to predict pan evaporation and the result owned a relative error ranging from 0.45% to 90%, and root mean square error of the prediction was 5.56 mm.