Comparative Analysis of CMIP5-Based Monsoon Season Rainfall Against Satellite-Based Estimations over India

摘要

Abstract The present study is designed to assess the rainfall pattern from Climate Model Inter-comparison Project Phase 5 (CMIP5) based on the satellite-derived rainfall products, Tropical Rainfall Measuring Mission (TRMM) over the Indian Region utilising daily as well as monthly rainfall data during monsoon season, ranging from 1st June to 30th September (JJAS). In this context, five best defined global climate models (GCMs) that participated in CMIP5 archive along with its multi-model mean (MMM) have been analysed to investigate the rainfall pattern during JJAS in terms of spatial map and time series under the forcing scenarios i.e., Representative Concentration Pathway 4.5 (RCP 4.5) and Representative Concentration Pathway 8.5 (RCP 8.5) from 2006 to 2018 over Indian region. On the other hand, spatial maps and time series have also been generated using TRMM rainfall data at daily (TRMM 3B42v7) and monthly (TRMM 3B43v7) scales during the reference time period. Thereafter, comparative study of the JJAS rainfall pattern between CMIP5 models and TRMM products has been carried out, whether the GCMs are able to simulate rainfall data reasonably well compared to satellite-derived estimates or not under various forcing scenarios over this region? Based on the assessment, it is noted that CMIP5 models have the ability to simulate daily mean monsoon season rainfall; however, it underestimates the rainfall intensity at daily scale over the north-east and south-west parts of India. Moreover, statistical analysis indicated more biases in the western coast and the north-eastern parts of India where it receives the highest amount of rainfall during JJAS. The outcomes presented here may be useful for assessing the reliability of CMIP5 models to project the rainfall pattern in near future under the various warming scenarios over the Indian Region.