Possibility of Predicting Indian Monsoon Rainfall on Reduced Spatial and Temporal Scales

Abstract

Three selected parameters have been analyzed for the spatial and temporal relationships with the Indian monsoon rainfall. These parameters are (i) the subtropical ridge position at 500 hPa over India in April, (ii) January?April Darwin surface pressure tendency, and (iii) January and February Northern Hemispheric surface air temperature. Multiple regression equations have been developed for forecasting monsoon rainfall on bimonthly to seasonal scales and on subdivisional to all-India scales. All equations have been verified by independent data. We obtain positive skill in forecasting the seasonal rainfall of not only all of India but also of its three large subregions and meteorological subdivisions lying in west-central parts of the country. Also, the skill is generally better for the forecast of rainfall for the latter half of the monsoon season than the whole season.