Demonstrating the air-sea coupling performance of a Regional Earth System Model: Indian summer monsoon a case study

An effort is made to implement a Regional Earth System Model (RESM) over the CORDEX-SA domain to demonstrate its skill in simulating the Indian summer monsoon characteristics. RESM was simulated on climate mode, 1980-2014, and showed good resemblance to observation in simulating mean precipitation, its variability (intraseasonal to interannual), extremes, and associated processes. RESM offers noticeable added value over its standalone atmospheric component (REMO), coupled model intercomparison project (CMIP5 and CMIP6), and regional climate models of CORDEX-SA. The added value is found to vary spatially. The most remarkable improvement is noticed over the Bay of Bengal (BoB), South-Central India, and Indo-Gangetic belt, where most standalone RCMs and coupled GCMs show limitations. The better representation of low-pressure systems both over land and ocean, sea surface temperature, Indian Ocean Dipole, and its underlying mechanism leads to improve mean precipitation. 

 

Keywords: RESM, CORDEX-SA, Indian summer monsoon, LPS, air-sea coupling

 

Acknowledgement: This work is jointly supported by the Department of Science and Technology (DST), Govt. of India, grant number DST/INT/RUS/RSF/P-33/G, and the Russian Science Foundation (Project No.: 19-47-02015).