Oscillation of potential evapotranspiration in India and its significance on seasonal potential water requirement of crops

Abstract

In this study, the normal weekly potential evapotranspiration values of 47 stations situated over different parts of the country have been subject harmonic analysis, The amplitude of the stations varies greatly ranging from 5 mm in the west coast of peninsular India to 24 mm over northwest parts of the country .The peak of weekly oscillation attains its maximum value around end of February/early March over extreme southwest coast of the country , while it is third week of June over northwest Rajasthan. northeast India and over small pockets around Rajamundry of Andhra Pradesh and Pusa of Bihar. A negative correlation between latitude and the seasonal (kharif, rabi and summer) potential water need of the respective stations of different groups indicates that potential water demand of crops at different seasons in each of the groups is inversely proportional with increase in latitudinal value except for kharif season of group IV stations where it is reverse.