An evaluation of CMIP5 and CMIP6 climate models in simulating summer rainfall in the Southeast Asian monsoon domain

Abstract

In this study, 28 climate models from the fifth phase of the Coupled Model Intercomparison Project (CMIP5) and 32 models from the sixth phase (CMIP6) have been evaluated for their ability to simulate large‐scale atmospheric circulations (using rainfall, wind fields, geopotential height, temperature, and moisture flux convergence) for the summer monsoon in Southeast Asia. Using a multi‐criteria decision making technique, models have been ranked based on 25 metrics which compare their performances with observation data. Results indicate a better representation of annual rainfall cycles as well as spatial pattern by CMIP6 models compared to CMIP5. Though majority of the models from both CMIPs show late onset and early retreat of the rainy season, CMIP6 GCMs simulate the onset, retreat, and the length of the rainy season closer to the observation. Large‐scale circulation patterns evaluated using spatial correlation and root mean square error (RMSE) show improvements in CMIP6 across all metrics, especially for the moisture flux convergence. Performances for large‐scale circulation are generally reflected in rainfall simulation; however, few models showed that better simulations of rainfall do not exclusively depend on their performance for large‐scale variables. Overall, CMIP6 models are found to be superior to CMIP5 models in simulating rainfall and large‐scale circulation, which is likely attributable to CMIP6 model's higher spatial resolutions, increased number of vertical levels, improved atmospheric and land surface parameterization, etc. Finally, subsets of optimal models from CMIP5 and CMIP6 that proved to be better at representing the summer monsoons in the study area are identified. These models are recommended to develop robust future projections that can be used for climate change impact and adaptation studies.

Projected changes in the near‐future mean climate and extreme climate events in northeast Thailand

“…Khadka et al . (2021) ranked 28 climate models from CMIP5 and 32 climate models from CMIP6 for their ability to represent regional climate in Southeast Asia, with an emphasis on the simulation of the summer monsoon rainfall using 25 metrics. In the current study, 14 top‐ranking models from CMIP5 and 8 models from CMIP6 under the High‐Resolution Model Intercomparison Project (HighResMIP), for which data were available at the time of the analysis, have been considered.…”

Asian rainfall anomaly patterns associated with interannual variations of early and peak summer rainfall over the Indochina Peninsula

“…Another issue worthy of future studies is how the climate models perform in simulating the spatial patterns of early and peak summer rainfall anomalies over Asia. A few previous studies have evaluated climate models in simulating and projecting the summer rainfall over Southeast Asia (Tangang et al ., 2020; Khadka et al ., 2021). We plan to analyse the relation of East and South Asian summer rainfall to that over the ICP based on CMIP6 model outputs.…”

Assessment of the Ability of CMIP6 GCMS to Simulate the Boreal Summer Intraseasonal Oscillation Over Southeast Asia

“…This study concluded that MJO propagation is significantly improved in CMIP6 models compared to CMIP5 models. Several other studies have evaluated the performance of CMIP6 models to simulate the mean climate at both the global and the regional scales (Pattnayak et al, 2017;Wu et al, 2019;Xin et al, 2020;Khadka et al, 2021). There was a strong agreement that CMIP6 models showed an overall improvement in the skill scores of the climate patterns compared with CMIP5 models.…”