Indian Journal of Science and Technology

Abstract

RegCM is a Regional Climate Model (RCM), mostly applied in regional climate change and seasonal prediction around the world. The International Centre for Theoretical Physics improves this model and releases updated version over years. In the present study a comparison was made between RegCM3 and RegCM4 versions of this model in simulating climate change over Cauvery Delta Zone of Tamilnadu. The simulations were made using ECHAM5 global climate model outputs of A1B scenario with a resolution of 25 km from 1971 to 2100. The comparison of yearly and decadal means indicated that there exists a significant and positive difference in simulation of rainfall and relative humidity by RegCM4 while solar radiation, maximum temperature, minimum temperature and wind speed showed significant negative difference. The Seasonal and monthly comparisons revealed that difference across weather variables is not consistent as that of yearly and decadal. The decadal projections showed a marked increase in maximum temperature, minimum temperature and rainfall. A slight increase in relative humidity and a slight decline in solar radiation and wind speed were noticed under RegCM4 simulations.
Keywords: RegCM3, RegCM4, Cauvery Delta Zone, A1B Scenario