Characteristics and Mechanisms of Remote Precipitation Events in Eastern China Induced by Tropical Cyclone

ABSTRACT

The Northwestern Pacific serves as the primary genesis region for tropical cyclones (TCs). TC‐induced remote precipitation (TRP) is a significant type of rainfall affecting China. On the basis of reanalysis datasets and statistical methods, the characteristics of TRP events over Eastern China during the summer from 1991 to 2020 are analysed. The potential mechanisms underlying TRP formation are further investigated, with a focus on moisture transport and ascending motion conditions. The results indicate that Eastern China is the primary region for TRP occurrence. The precipitation pattern of TRP events exhibits a southwest to northeast oriented distribution, with the core precipitation region exhibiting a horizontal radius of 500 km. In addition, during the formation of TRP events, TCs exert influence through their intrinsic circulation and can trigger anomalous quasistationary Rossby waves that propagate meridionally, thereby modifying the East Asian circulation pattern. This process results in an anomalous easterly jet extending from the ocean to the precipitation region. Such moisture transport is more notable in the middle–lower troposphere. Furthermore, two anomalous ascending motion regions exist in Eastern China. The upper‐ and lower‐level jet configuration, the anomalous meridional temperature advection and the anomalous vertical variation in horizontal vorticity advection induced by TCs provide favourable ascending conditions for TRP formation. The configuration of upper‐ and lower‐level jets provides favourable convergence and divergence conditions, respectively, for TRP formation. While the anomalous meridional temperature advection exerts a greater influence on the formation of northward‐displaced anomalous ascending motion, the anomalous vertical variation in vorticity advection plays a more critical role in shaping southward‐displaced anomalous ascending motion. Overall, this study demonstrates that TC activity and its feedback effects on large‐scale circulation are the primary drivers of the formation of TRP events in Eastern China.