Analysis of precipitation and streamflow extremes and quantification of uncertainties under climate change in a humid tropical river basin

Abstract

Climate change, a challenging global concern, is referred to as the defining issue of newlinepresent times. Anthropogenic interventions have increased the concentration of newlinegreenhouse gases in the atmosphere. This has resulted in warming of the planet, leading newlineto changes in the Earth s climate. Changes in climate alter the magnitude, frequency, newlineduration and spatial extent of extreme hydro-meteorological events. The severity of newlineimpact of these extreme events depends on the degree to which the civil society is newlineexposed and is vulnerable. Studies focussing on hydro-meteorological extremes and newlineassociated uncertainties facilitate the formulation and implementation of appropriate newlineadaptation and mitigation strategies so that the adverse impacts of these events on the newlinesociety can be reduced to a considerable extent. newlineIn this study, the impact of projected climate change on precipitation and streamflow newlineextremes in the Chaliyar river basin in the State of Kerala, India is addressed. In order to newlineassess the impact of climate change on future precipitation extremes, the precipitation newlinereturn levels at Kottamparamba, Manjeri and Nilambur raingauge stations under the newlinerepresentative concentration pathways (RCPs) 4.5 and 8.5 in the near (2021-2050) and newlinefar future (2071-2099) periods were determined for different return periods. Reliability newlineensemble averaging was performed with the annual maximum precipitation (AMP) newlineseries derived from the dynamically downscaled projections of seven global climate newlinemodels (GCMs), viz., ACCESS1.0, CNRM-CM5, MPI-ESM-LR, NorESM1-M, newlineCanESM2, CSIRO-Mk3.6 and IPSL-CM5A-LR. The projections of the first four GCMs newlinewere downscaled using the regional climate model (RCM) CCAM whereas the newlineprojections of the other three GCMs were downscaled using the RCM RegCM4. newline