Abstract
Analysis of observed Indian Summer Monsoon precipitation reveals more increase in extreme precipitation (in terms of its magnitude) over south India compared to north and central India during 1971–2017 (base period: 1930–1970). In the future, analysis of precipitation from the Coordinated Regional Downscaling Experiment indicates a southward shift of precipitation extremes over South Asia. For instance, the Arabian Sea, south India, Myanmar, Thailand, and Malaysia are expected to have the maximum increase (~18.5 mm/day for RCP8.5 scenario) in mean extreme precipitation (average precipitation for the days with more than 99th percentile of daily precipitation). However, north and central India and Tibetan Plateau show relatively less increase (~2.7 mm/day for RCP8.5 scenario). Analysis of air temperature at 850 mb and precipitable water (RCP4.5 and RCP8.5) indicates an intensification of Indian Ocean Dipole in future, which will enhance the monsoon throughout India. Moisture flux and convergence analysis (at 850 mb) show a future change of the direction of south-west monsoon winds towards the east over the Indian Ocean. These changes will intensify the observed contrast in extreme precipitation between south and north India, and cause more extreme precipitation events in the countries like Myanmar, Thailand, Malaysia, etc.
Highlights
Analysis of observed Indian Summer Monsoon precipitation reveals more increase in extreme precipitation over south India compared to north and central India during 1971–2017
Most of the above studies used coarse resolution General Circulation Model (GCM) data for analysis, whereas the use of fine-resolution data can help in better understanding the dynamics of monsoon over South Asia[15]
Spatio-temporal changes in precipitation extremes for the past and future period are analyzed, and its possible causes are identified for the regions affected by Indian Summer Monsoon (ISM), i.e., Indian Ocean, eastern Africa, and south Asia
Summary
Analysis of observed Indian Summer Monsoon precipitation reveals more increase in extreme precipitation (in terms of its magnitude) over south India compared to north and central India during 1971–2017 (base period: 1930–1970). The mean daily precipitation during the entire future period (2006–2100) for RCP8.5 is projected to increase in most parts of south Asia and the Indian Ocean (~84.2% of the study area).
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