Have Rainfall Extremes Shifted over the Western Indian River Basins in the Last 119 years ?
Abstract
In the last few decades, Indian River Basins (IRBs) experienced more frequent and severe floods due to increasing extreme rainfall. This study used Generalized Extreme Value distribution (GEV), Expert Team on Climate Change and Detection Indices (ETCCDI), and Standardized Precipitation Index (SPI) to evaluate the changes in rainfall extremes over the IRBs using 119 years of observed high-resolution gridded rainfall data (1901-2019) obtained from India Meteorological Department (IMD). The study illustrates a noticeable shifting trend in extreme rainfall events toward the central and western IRBs during the recent decades of 1981-2019 at 40-year time intervals. A significant trend at 10-, 30-, and 100-year return levels has been observed in maximum annual rainfall. The study resulted that the Ganga, west-flowing river basins of Peninsular and Northeast India, experienced the maximum spatial variability of heavy rainfall events in recent decades from 1981-2019. The decadal changes in rainfall showed the shifting and increase in (15% -58.74 %) rainfall pattern based on the grid during the last decades of the 20th and current 21st century over the west-flowing river basins. The IRBs experienced good rainfall, with an 8% increase in mean rainfall anomaly above normal. This research highlights the increasing trend in rainfall extremes, which may pose a grave risk to agriculture, human life, and infrastructure, predominantly to the vulnerable sections of society. Also, it frames hydrological hazard-centric policies and formulates regional preparedness plans for national-scale mitigation and adaptation measures.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2022
- Bibcode:
- 2022AGUFM.A46E..10C