Historical and projected relationships between the Tibetan Plateau summer monsoon and precipitation in Central Asia based on multi-CMIP6 models

Based on the historical and SSP1-2.6, SSP2-4.5 and SSP5-8.5 experiments from20 Coupled Model Inter -comparison Project phase 6 (CMIP6) models, the historical and projected relationships between the Tibetan Plateau summer monsoon (TPSM) and precipitation in Central Asia (CA) are investigated. The historical ex-periments show that the CMIP6 models have large uncertainties in simulating the relationships between the TPSM and the Central Asian precipitation and their corresponding dynamic processes. 60% (12) of the CMIP6 models can simulate the close positive correlation between the TPSM and the precipitation in the key region (37 degrees-45 degrees N, 65 degrees-85 degrees E) of CA, but only 8 of them can capture the dynamic processes linked the TPSM and the precipitation in CA during 1971-2010. So we select the 8 models out of the 20 based on their skills in capturing the dynamical processes as observed. Regression analysis shows that the 8 selected models will still simulate the positive correlation between the TPSM and the precipitation in CA and capture their linked dynamic progresses during the second half of 21st century (2050-2099), but with the rising of emission scenarios, the significant area of correlations will gradually shrink. During 2050-2099, 75% of the 8 selected models suggest the TPSM will strengthen, especially in northern monsoon regions, corresponding to significant increase of summer precipi-tation in the key region (37 degrees-45 degrees N, 65 degrees-85 degrees E) of CA in SSP1-2.6 and SSP2-4.5 experiments. In SSP5-8.5 experiment, 6 out of the 8 selected models also indicate the TPSM will strengthen in the northern monsoon region, corresponding to significant increase of precipitation in most of key region and decrease in eastern key region.