A preliminary assessment of observed and projected trends in the diurnal temperature ranges over South India under SRES A1B scenario

摘要

In the present study, the PRECIS, a regional climate model, is employed to simulate the baseline (1970-2000) and future 2071-2100 (2080s) maximum, minimum and diurnal temperature range changes under SRES A1B scenario over the Kancheepuram district of Tamil Nadu, South India. A comparison of the simulated baseline results with observation data acquired from IMD show that PRECIS can well simulate the local distribution characteristics of diurnal temperature range over the study area with a correlation coefficient (R2) value of 0.948 with 1% significance level. Analyses of the simulated results in the 2080s under SRES A1B scenario relative to the baseline shows that there would be an overall increasing trend in the maximum and minimum temperatures over the study area and the warming amplitude in the north, west and interior parts are projected to be greater than in the east coastal areas. Sen's slope estimator supported by the Man Kendal test shows that the diurnal temperature range in the 2080s under SRES A1B scenario relative to the baseline are projected to decrease annually by -0.015 degrees C and a statistically significant decrease of -0.029 degrees C during the southwest monsoon season in the overall study area.