COLA AGCM simulation of the effect of anomalous spring snow over Eurasia on the Indian summer monsoon

The ability of the Center for Ocean-Land-Atmosphere Studies Atmospheric Gen eral Circulation Model to capture the inverse snow-monsoon relation observe d in satellite-derived data is tested. The effect of initial enhanced and r educed spring Eurasian snow mass on the evolution of the subsequent Indian summer monsoon is examined through 11-member ensemble integrations from 1 M arch to 1 October The results of the sensitivity experiment indicate that r emote responses from the snow-mass anomalies include significant changes in the sensible-heat flux, latent-hear flux and sea level pressure, leading t o changes in summer precipitation over the land mass of the Indian subconti nent. Fur the pre-monsoon season, the ensemble average of the temperature o f the atmospheric column for enhanced snow mass is anomalously colder over large-scale regions of the Eurasian continent compared with the ensemble av erage for the reduced snow mass. Low-level south-westerlies associated with monsoonal circulation are increased. The results indicate the importance o f land-surface processes in the evolution of the monsoon circulation and le nd hope to the use of Eurasian spring snow mass towards improved forecastin g of the summer monsoon.