Himalayan winter snow cover area and summer monsoon rainfall over India

Abstract

The study presented in this paper examines the relationship between satellite‐derived Himalayan snow cover extent in the winter season (December to March) and the amount of summer monsoon rainfall for the period 1971 to 1980. Himalayan snow cover area has been derived from satellite images and northern hemisphere snow cover charts produced by the National Oceanic and Atmospheric Administration‐National Environmental Satellite Service. Indian summer monsoon rainfall was the area‐weighted mean of all meteorological subdivisions of India for the months June through September. The variations of Indian summer monsoon rainfall were compared with the variation of the Himalayan winter snow cover area. There is an inverse relationship (negative correlation) between these two variables, which indicates that more than mean Himalayan winter snow cover area is to be followed by less than normal (India Meteorological Department (IMD)) summer monsoon rainfall over India. The inverse relationships hold true for 8 out of 10 years of the study period. The coefficients of correlation between the Himalayan snow cover area departures from the 10‐year mean and the rainfall departures from IMD normals for all the meteorological subdivisions of India were computed. The negative correlations were found to be maximum in the region between 18°N latitude and the foothills of the Himalayas.