What have we learned about the Indian monsoon from satellite data?

Abstract

In the pre-satellite era, our understanding of the monsoon was based primarily on ground-based observations. The land-sea contrast in surface temperature was considered the primary mechanism that drives the monsoon. During the last 47 years a large amount of data has been obtained from satellites and this has altered our perception about the factors that influence monsoon rainfall. The satellite data has revealed that the clouds in the tropics move eastward along the equator and poleward from the equator to higher latitudes. The net radiant energy available to earth-atmosphere system was found to be a fundamental driving force for monsoon rainfall. The role played by water vapour in controlling vertical stability, latent heat of condensation and greenhouse effect was appreciated better after the advent of satellite data.