Unraveling the Global Teleconnections of Indian Summer Monsoon Clouds: Expedition from CMIP5 to CMIP6

TL;DR

This study compares CMIP5 and CMIP6 climate models, showing CMIP6 models have improved accuracy in simulating Indian Summer Monsoon cloud patterns, rainfall, and teleconnections with global sea surface temperatures, aiding seasonal prediction.

Contribution

It demonstrates that CMIP6 models provide more realistic teleconnection patterns and better rainfall bias correction over the Indian Summer Monsoon region compared to CMIP5.

Findings

CMIP6 models show stronger teleconnection with global SST.

CMIP6 reduces rainfall bias over the ASM region.

CMIP6 improves spatial correlation with observations.

Abstract

We have analyzed the teleconnection of total cloud fraction (TCF) with global sea surface temperature (SST) in multi-model ensembles (MME) of the fifth and sixth Coupled Model Intercomparison Projects (CMIP5 and CMIP6). CMIP6-MME has a more robust and realistic teleconnection (TCF and global SST) pattern over the extra-tropics (R ~0.43) and North Atlantic (R ~0.39) region, which in turn resulted in improvement of rainfall bias over the Asian summer monsoon (ASM) region. CMIP6-MME can better reproduce the mean TCF and have reduced dry (wet) rainfall bias on land (ocean) over the ASM region. CMIP6-MME has improved the biases of seasonal mean rainfall, TCF, and outgoing longwave radiation (OLR) over the Indian Summer Monsoon (ISM) region by ~40%, ~45%, and ~31%, respectively, than CMIP5-MME and demonstrates better spatial correlation with observation/reanalysis. Results establish the credibility of the CMIP6 models and provide a scientific basis for improving the seasonal prediction of ISM.