The summary on the variability and change of the regional climate system based on the 16 chapters in this book is as follows.
The analysis of rainfall over India is based on the quality-controlled district rainfall
data for the period 1901-2010.
- 1. The all-India southwest monsoon rainfall does not show any long-term trend, but it exhibits significant multi-decadal variability.
- 2. However, there are significant regional trends in southwest monsoon rainfall. Monsoon rainfall in the meteorological subdivisions of Jharkhand, Chhattisgarh and Kerala have shown significant decreasing trends. However, monsoon rainfall over Gangetic West Bengal, West Uttar Pradesh, Jammu and Kashmir, Konkan and Goa, Madhya Maharashtra, Rayalaseema, Coastal Andhra Pradesh and North Interior Karnataka showed increasing trends.
- 3. Monsoon rainfall in the month of July has shown decreasing trends over most parts of central India. However, June and August rainfall has shown increasing trend over the central and southwestern parts of the country.
- 4. Northeast monsoon (October-December) over southeast peninsula does not show any significant trend, but shows multi-decadal variability.