Patel Hemlata^1,, Gadgil Alka², Krishnakumar G³

The Indian summer monsoon affects almost all the facets of life in India. Variability in the onset and duration of monsoon has profound impacts on water resources, human life, agriculture, economics and ecosystems. That is why predictions of the monsoon behavior are eagerly watched by government planners and agronomists. However, every monsoon has its own unique characteristics, which makes it more enigmatic and complex. Predicting the likely physical behavior of the monsoon system and the resulting distribution of rainfall over different parts of India is an extremely challenging task. Sometimes, the necessity of producing long-range forecasts has compelled investigators to develop empirical relationships between different facets of the coupled atmosphere-ocean land system. The present study also presents some empirical evidence of relationships between summer monsoon rainfall and sea-surface temperature over the Indian Ocean. Sea surface temperatures exert significant control over the atmosphere, particularly over the monsoon circulation. The study has identified four pockets in the Indian Ocean, which can be used as potential predictor zones for summer monsoon rainfall (June to September) over India. To achieve this objective, correlation analysis with lags in months was carried out to establish association between the sea surface temperature over the four pockets and summer monsoon rainfall. Strong significant association can be found between the SST of these four pockets and Indian summer monsoon rainfall. The study also reveals a phase-change in the relationship between the sea surface temperature and Indian summer monsoon rainfall, particularly in the recent period.

sea surface temperature, lag correlation, Indian summer monsoon rainfall (ISMR)