The Relationship between the East Asian Subtropical Westerly Jet and Summer Precipitation over East Asia as Simulated by the IAP AGCM4.0

摘要

Based on a 30-year Atmospheric Model Intercomparison Project(AMIP) simulation using IAP AGCM4.0, the relationship between the East Asian subtropical westerly jet(EASWJ) and summer precipitation over East Asia has been investigated, and compared with observation. It was found the meridional displacement of the EASWJ has a closer relationship with the precipitation over East Asia both from model simulation and observation, with an anomalous southward shift of EASWJ being conducive to rainfall over the Yangtze-Huaihe River Valley(YHRV), and an anomalous northward shift resulting in less rainfall over the YHRV. However, the simulated precipitation anomalies were found to be weaker than observed from the composite analysis, and this would be related to the weakly reproduced mid-upper-level convergence in the mid-high latitudes and ascending motion in the lower latitudes.