PREMONSOON MAXIMUM AND MINIMUM TEMPERATURES OVER INDIA IN RELATION TOTHE SUMMER MONSOON RAINFALL

The pre-monsoon thermal field over the Indian landmass has an importan t bearing on the land-sea heating contrast in the region, consequently influencing the establishment, advance and overall performance of the Indian summer monsoon rainfall. This paper examines the relationship between the pre-monsoon thermal field over India and the following sum mer monsoon rainfall, in order to identify possible predictors for lon g-range forecasting of Indian summer monsoon rainfall. Based on the sp atial patterns of correlations of monsoon rainfall with maximum and mi nimum temperatures at 121 stations well distributed over India, during the recent period 1951-80 two predictors showing a significant contri bution to the variance in monsoon rainfall have been identified. They are (i) March minimum temperature in east peninsular India and (ii) Ma y minimum temperature in west central India. These two predictors have performed very well in terms of their significant contribution to the multiple regression models during 1951-1987, vis-a-vis several other known predictors. They have also shown a consistently significant rela tionship with the monsoon rainfall during the recent period, from the mid-1940s till the end of the data period. A stepwise regression model for long-range forecasting of all-India summer monsoon rainfall, invo lving three regional predictors, has been developed, and has shown a m ultiple correlation of 0.89. (C) 1997 by the Royal Meteorological Soci ety.