Hydro-climatic characteristics of hill stations of India

Abstract

Hydro climatic characteristics of 18 hill stations selected from all regions of the country is taken up in the present investigation. Climatic shifts and stability, normal as well as extremities of water budget elements at all the 18 selected stations for the 1961-2010 period are obtained through study of inter annual variation of humidity, aridity and moisture indices. Decadal frequency of climatic shifts, influence of ENSO and La Nina events on moisture index and extremities of water budget elements at individual stations is another aspect that is studied. It is appropriate that frequency of occurrence and intensities of humid (Flood) and drought events are studied during southwest monsoon season rather on annual basis, as 75% of annual rainfall occur during southwest monsoon season. Also several studies concluded that performance of southwest monsoon has teleconnection to the ENSO and La Nina phenomena. Frequency of occurrence and intensities of humid (Flood) and drought events have been obtained through study of inter seasonal variation of humidity and aridity indices during southwest monsoon season. Trend in seasonal humidity index and the influence of ENSO and La Nina events, in the study period, on the humidity and aridity indices is also presented. Region- wise and decadal frequency of occurrence of humid / drought events is brought out. Percentage occurrence of total humid events over all 17 moist climate hill stations put together, category wise as well as total, along with their trend is also brought out. Potential evapotranspiration and precipitation are computed on a monthly basis to force the revised Thronthwaite and Mather water balance model to derive the basic water budget elements and thereby other parameters