Characteristics of Moisture Transport in Rainstorms in Different Regions of Eastern China Under the Background of Northeast China Cold Vortex in Warm‐Season

Abstract Revealing the characteristics of moisture transport in heavy rainfall events in eastern China under the Northeast China Cold Vortex (NCCV) background holds important scientific and practical value for improving precipitation prediction accuracy. This study uses reanalysis data, surface observations, and a Lagrangian trajectory model to compare the characteristics and moisture transport mechanisms of NCCV and non‐NCCV (NNCCV) rainstorms in Northeast China (NEC), North China (NC), and the Yangtze‐Huaihe River basin (YHR). The results show that: (a) The high‐value area of NCCV rainstorm intensity in NEC is located along the southern coast; in NC, rainstorms are in the southeast, with NNCCV rainstorms being more intense. In YHR, NCCV rainstorms are distributed along the Yangtze River, while NNCCV rainstorms are concentrated in the central‐north and southeastern coast. NCCV rainstorm frequency peaks in July in NEC and NC, and in June in YHR. The NCCV significantly changes the rainstorm distribution in YHR in June and August. All three regions show an upward trend in NCCV rainstorm frequency, with the fastest increase in YHR. (b) For NCCV rainstorms in NEC, the southwest pathway moisture contributes the most (40%), while NNCCV rainstorms are dominated by the southeast pathway (48%). In NC, both NCCV and NNCCV rainstorms are primarily influenced by the southwest pathway moisture (45% and 42%, respectively). In YHR, the southeast pathway moisture accounts for 62% of NCCV rainstorms, compared to 46% for NNCCV rainstorms. (c) In NEC, the NCCV easily triggers strong local cyclonic convergence, with more moisture from the eastern coast than usual. In NC, the NCCV introduces dry and cold air during rainstorms, reducing moisture but enhancing dynamic uplift through north‐south wind convergence. In YHR, the southward shift of the NCCV interacts with the western Pacific subtropical high, leading to collisions between dry easterly currents and warm moist southwesterly jets, triggering convective instability and intensified precipitation.