ASSESSING THE IMPACT OF CLIMATE CHANGE IN PONNANIYAR BASIN OF TAMIL NADU BASED ON REGCM 4.4 SIMULATIONS

Abstract. Climate change induced extreme weather events such as drought and flood condition are likely to become more common and associated impacts on crop production will be more without proper irrigation planning. The present investigation was undertaken for assessing the impact of Climate change on tomato yield and water use efficiency (WUE) using AquaCrop model and RegCM 4.4 simulations. The water driven AquaCrop model was validated based on observation of field experiment conducted with four different dates of sowing (1st November, 15th November, 1st December, 15th December) at Ponnaniyar basin, Tiruchirappalli. Validation of AquaCrop model indicated the capability of AquaCrop in predicting tomato yield, biomass and WUE close to the observed data. Seasonal maximum and minimum temperatures over Tiruchirappalli are projected to increase in the mid-century under both RCP4.5 and RCP8.5 scenarios. Maximum temperature is expected to increase up to 1.7 °C/2.5 °C in SWM and 1.9 °C/2.9 °C in NEM by the mid of century as projected through stabilization (RCP 4.5) and overshoot emission (RCP 8.5) pathways. Minimum temperature is expected to increase up to 1.6 °C/2.2 °C in SWM and 1.6 °C/2.1 °C in NEM by the mid of century as projected through stabilization (RCP 4.5) and overshoot emission (RCP 8.5) pathways. Seasonal rainfall over Tiruchirappalli is expected to decrease with RCP4.5 and RCP8.5scenarios with different magnitude. Rainfall is expected to change to the tune of −1/−11 per cent in SWM and −2/−14 per cent in NEM by the mid of century as projected through stabilization (RCP 4.5) and overshoot emission (RCP 8.5) pathways.