Advances in CMIP6 INM-CM5 over CMIP5 INM-CM4 for precipitation simulation in South Korea

This study compared the historical and future simulations of precipitation in South Korea from INM-CM4 of Coupled Model Intercomparison Project (CMIP) 5 and INM-CM5 of CMIP6 to identify their differences for the projections of corresponding scenarios by three timeframes (annual, summer and winter) and four regions (NW, NE, SW and SE). Six performance indicators were used to quantify the models' reproducibility to precipitation at 22 stations in South Korea for the historical period (1970-2005). Then, the change rates of precipitations in near and far futures (2020-2059 and 2060-2099) were calculated for two representative concentration pathway (RCP) 4.5 and 8.5 and socioeconomic shared pathway (SSP) 2-4.5 and 5-8.5. Their uncertainties were also quantified using standard deviations and interquartile ranges. As a result, CM5 clearly showed a 7.4% improvement in six performance indicators. The change rates in far future were larger but the uncertainties were smaller. But both the rates and uncertainties in NW were the largest. Also, the uncertainties in INM-CM5 were also smaller than in INM-CM4 for all timeframes and the differences between RCP4.5 and SSP2-4.5 were absolutely larger than those between RCP8.5 and SSP5-8.5.

Automated summary

This study compared the historical and future simulations of precipitation in South Korea using different models, and identified differences in projections for different scenarios. Results showed that CMIP6 models performed better, with higher precipitation change rates and lower uncertainties in the future, particularly in the NW region. Differences between RCP4.5 and SSP2-4.5 were larger than between RCP8.5 and SSP5-8.5.