ALBERT

Description: Abstract This study presents a comprehensive and quantitative evaluation on the mean state of summer atmospheric circulation over East Asia. Attention is paid to the South Asian high (SAH), western North Pacific subtropical high (WNPSH) and Indian low (IL) at upper, middle and lower troposphere, respectively. 31 state‐of‐the‐art climate models from phase 5 of the Coupled Model Intercomparison Project (CMIP5) are used as example for the analysis. Most models can basically simulate the three closed‐circulation systems (CCSs), although there is a certain inter‐model spread and an underestimation of their intensity. In terms of geographic location, models have the best performance for SAH and the poorest performance for WNPSH. The latter shows generally a south‐westward shift compared to NCEP reanalysis. Five atmospheric fields (zonal and meridional wind at 850hPa, geopotential height at 500 and 100hPa, and sea level pressure) are inspected and generally well reproduced in models, with Taylor‐S indices all larger than 0.84 for 90% of the models. The best performance is for 500hPa geopotential height with an average Taylor‐S index of 0.98. Models skill in simulating the sea level pressure is the lowest. It shows however a significant positive correlation with models’ resolution. Almost all models underestimate 100hPa geopotential height over East Asia, mainly due to the common cold bias in the troposphere. As a whole, CCSM4, CNRM‐CM5, CESM1‐CAM5 and NorESM1‐M are identified as high‐skill models for simulating the East Asian atmospheric circulation. High‐skill models show a better simulation of precipitations in East China as well, with 21.3% decrease of dry biases in Southeast China. It is also shown that the physical explanation for this linkage resides in the center position of the western North Pacific subtropical high which determines the quality of 850hPa winds and water vapor transport in Southeast China.