Trends in Precipitation Extremes over India - (IMD), Pune

6. ConclusionsFrom the present study, the following main conclusions can be drawn.1. Most of the extreme rainfall indices have shown significant positive trendsover the west coast stations and northwestern parts of Peninsula(Maharashtra). Along the west coast, contribution from the heaviest (95and 99 percentile) events to the total seasonal rainfall has increasedsignificantly. This result is important in view of the recent deluge occurredover Mumbai.2. Positive trends were also observed over the region 20 0 to 30 0 N and 75 0 to80 0 E.3. Individual stations over North east India did not show any significanttrends. However, averaged over the area, some climate indices(R75pTOT, R95p, R95pTOT) showed increasing trends.4. It is interesting to note that two hilly stations considered in this study(Simla and Mahabaleshwar) have shown significant decreasing trends ofsome extreme rainfall indices.Changes in the climate indices revealed in this study may be associated withvariability in the large-scale atmospheric circulation patterns. However, to whatextent the trends observed in this study are related with atmospheric circulationchanges needs to be addressed in future studies.The area of concern is northern parts of west coast and adjoiningMaharashtra. This study suggested that extreme rainfall events over this region hasshown a significant increasing trend. The study of Guhathakurta and Rajeevan(2006) has brought out the result that this region has also witnessed significantincrease in monsoon seasonal and annual rainfall. This inference was also madeusing about 100 years of rainfall data. Using a high resolution regional climatemodel, Rupa Kumar et al. (2006) have shown in the global warming scenario,summer monsoon precipitation over most parts of Maharashtra and adjoining southGujarat region is expected to increase on an average by 5 mm/day. This will10