Classification of Summer Extratropical Cyclones Over Northeast China and Their Impacts on Regional Precipitation

Based on the ERA5 six‐hourly reanalysis data set and objective identification and tracking methods for extratropical cyclones (ECs), this study identified 423 summer ECs that passed through Northeast China (NEC) during 1979–2023. These ECs were categorized into three distinct types using K ‐means clustering based on their genesis locations. We further examined the associated atmospheric circulation patterns and the resulting climatic impacts of each EC type on summer precipitation over NEC. The results indicate that: Type 1 (47.04%) originates from NEC and eastern Mongolia, driven by the southward development of an upper‐level trough over the west of Lake Baikal, accompanied by pronounced westerly anomalies. Type 2 (27.66%) originates from western and central Mongolia. Its formation involves an upper‐level trough extending from western Mongolia to the region west of Lake Baikal, accompanied by significant westerly anomalies over central‐western Mongolia and NEC. Both Type 1 and Type 2 primarily track eastward, inducing moisture transport anomalies from the western boundary into NEC, producing precipitation over the northern and central parts. In contrast, Type 3 (25.30%) originates from the eastern coastal regions of China. Driven by a deepening upper‐level trough from North China to NEC and enhanced westerlies toward the Sea of Japan, these ECs move northeastward, steering significant moisture flux anomalies from the southern boundary into the region, producing precipitation over the southern and central parts. This study provides a new perspective on the mechanisms of regional precipitation over NEC.