Interrelationship between temperature index and South-West monsoon rainfall: Historical analysis and future projections

B. S. THANUSHREE; R. H PATIL; J. VASANTHAKUMARI

B. S. THANUSHREE Department of Agricultural Meteorology, College of Agriculture, Dharwad University of Agricultural Sciences, Dharwad - 580 005, India
R. H PATIL Department of Agricultural Meteorology, College of Agriculture, Dharwad University of Agricultural Sciences, Dharwad - 580 005, India
J. VASANTHAKUMARI Department of Agricultural Statistics, College of Agriculture, Dharwad University of Agricultural Sciences, Dharwad - 580 005, India

Keywords: Rainfall, South west monsoon, T_Index, Temperature

Abstract

The South-West monsoon also known as Indian Summer Monsoon (ISM), which is part of the South Asian monsoon system, is one of the largest global phenomena of the general circulation that has its impacts on the global weather and climate. In this study the spatial and temporal correlations were analysed with a Rainfall and Temperature based Index namely, T_Index. This index is developed by taking the product of the Near Surface Air Temperature, Latent Heat Flux and Mean Sea Level Pressure, to understand the inter-annual variability of the ISM rainfall for both the historical (1991-2020) and projected (2021-2050) periods. The monthly data were downloaded from Copernicus website, Coupled Model Inter Comparison Project Phase 6 (CMIP6) with a resolution of 0.5º x 0.5º. The data were processed by using the FERRET and CDO software in the LINUX platform. The results showed that in the historical period (1991-2020), there was a highly positive correlation between T_Index and rainfall throughout India except during 1991 to 2000 period in central and eastern parts of India. For the projected period (2021-2050), there likely to be positive correlation between the T_Index and rainfall throughout India except for north-eastern regions of India.