Abstract:
Water is vital to life. India is an agriculture based economy more than 50
percent of the population dependents on the agriculture. More than 60 percent of
agricultural land is rain fed. The main source of water is summer monsoon rainfall as
78 percent of total annual rainfall occurs in the monsoon period. Though the summer
monsoon rainfall varies on inter annual basis. The variation in the summer monsoon is
modulated by two phenomena El Nino Southern Oscillation (ENSO) and recently
discovered Indian Ocean Dipole (IOD).
We used lITM rainfall data, Aphrodite's gridded precipitation data and
TRMM rainfall data. To study the impact of ENSO and IOD on the Indian rainfall.
Temporal as well as spatial variation of rainfall due to ENSO and IOD is studied.
Their Impact on extreme rain events, relation of intensity is also studied.
The results suggest that ENSO greatly influenced the Indian Summer
* Monsoon Rainfall in the last century. ENSO can attribute nearly 20 percent of the
variance in the ISMR. The relation is changing now, influence of ENSO is getting
weaker while that of IOD is increasing since past two decades. The impact of ENSO
as well as IOD varies spatially throughout the country. Some parts have more impact
other have lesser. Their impact on EREs is also varies spatially. There is no profound
impact is observed on the intensity of rainfall.
Hence in the agricultural planning and in management of water resources. The
knowledge of ISMR relation with ENSO and IOD can very useful to water managers
and for well-being of 1.2 billion people of the country.
