TN-70 : Long range forecasting onset of drought condition in tropics and sub tropics

Abstract

Droughts of great magnitude in various tropical and sub-tropical regions have been a matter of concern in the recent past. Their socio-economic consequences have resulted in the studies and research on predicting the droughts well in advance. The long range prediction of droughts has been based on the analysis of various meteorological events that usually prevail before the drought occurs.

The present note deals with the long range forecasting of onset of drought conditions in tropics and subtropics with special emphasis on forecasting of Indian monsoon, the ill distributed rainfall accompanying which results in droughts over different parts of India. The meteorological conditions in tropics and subtropics have been emphasised in the note and the physical linkages of various parameters as atmospheric circulations, surface temperature, sea surface pressure and temperature, El Nino and Southern Oscillation, sunspot cycles and snow cover with drought conditions have been discussed. The techniques applied in long range forecasting of rainfall in tropics, specially in India have been reviewed.