Evaluation of CMIP6 GCM rainfall in mainland Southeast Asia

Abstract Global climate models (GCMs) of Coupled Model Intercomparison Project 6 (CMIP6) has designed with new socioeconomic pathway scenarios to incorporate the socioeconomic changes along with greenhouse gas emissions to project future climate. Performance of 35 GCMs of CMIP6 was evaluated in this study in replicating APHRODITE rainfall in the Mainland South-East Asia (MSEA) for the period 1975–2014. Compromised programming (CP) based on four spatial statistical metrics were used for the ranking of the GCMs and Jenk's natural break classification was employed to find the most suitable subset of GCMs for MSEA. The results showed that majority of CMIP6 GCMs can capture the rainfall climatological of MSEA. The performance of the GCMs was different in terms of different metrics. Integration of all metrics using CP showed MRI-ESM2-0, EC-Earth3 and EC-Earth3-Veg as the most suitable subset of GCMs for rainfall projections in MSEA. The performance assessment of the selected GCMs revealed their ability to simulate the annual mean rainfall climatology in the central and southern region of MSEA with a bias less than 25%. Relatively higher biases (−25 to −75%) were noticed in the western coastal region of Myanmar where observed rainfall is the highest. The identified CMIP6 GCMs can be employed for climate change projections and impact assessments in MSEA after correcting the associated biases.