大气科学2025，Vol.49Issue(4)：1046-1065,20.DOI:10.3878/j.issn.1006-9895.2402.23144
中国东部夏季季节内降水异常的经向移动分类及可能机理
Classification of the Subseasonal Meridional March of Summer Precipitation Anomalies over Eastern China and Possible Mechanisms
摘要
Abstract
Understanding the classification of the subseasonal meridional march of summer precipitation anomalies in eastern China is crucial for analyzing the dynamics of East Asian summer monsoon and improving rainband predictions.However,previous studies on precipitation classification primarily focused on subseasonal propagation,leaving the broader regularity and classification of these anomalies over eastern China unclear.Therefore,this study addresses the gap by categorizing the subseasonal meridional movement of summer(24-50 pentad)precipitation anomalies into three types using the K-means clustering method:(1)The northward propagating type in which precipitation anomalies move northward from South China;(2)the oscillating type in which precipitation anomalies remain stable,with opposing phases north and south of 30°N;(3)the southward retreating type in which the precipitation anomalies move southward from the Huang-Huai River Basin.Across all three types,anomalous convection over the tropical Indian Ocean propagates northeastward.However,whether these anomalies influence eastern China largely depends on the speed and intensity of the mid-latitude disturbances over East Asia.When the westerly jet over eastern China is strong and wide,mid-latitude disturbances move eastward quickly.However,if the wave activity flux transported to East Asia is inactive,these disturbances struggle to develop.Under such conditions,tropical anomalous convection often propagates northward,leading to the formation of the northward propagating type.If the westerly jet over eastern China is weak but the wave activity flux propagated to East Asia is active,mid-latitude disturbances move slowly and remain stable.These disturbances can strengthen and develop further through active upstream wave energy transport,which blocks the northward propagation of tropical anomalous convection,forming the oscillating type.If both the westerly jet and wave activity flux are strong,mid-latitude disturbances intensify and propagate southward,formulating the southward retreating type.关键词
中国东部降水异常的季节内移动/K均值聚类分析/热带对流/中纬度扰动Key words
Subseasonal march of precipitation anomalies over eastern China/K-means clustering analysis/Tropical convection/Mid-latitude disturbance分类
天文与地球科学引用本文复制引用
李娟,王诚,徐邦琪,朱志伟..中国东部夏季季节内降水异常的经向移动分类及可能机理[J].大气科学,2025,49(4):1046-1065,20.基金项目
国家自然科学基金项目42088101、42175056,江苏省基础研究计划自然科学基金青年基金项目BK20231110 National Natural Science Foundation of China(Grants 42088101,42175056),Natural Science Foundation of Jiangsu Province(Grant BK20231110) （Grants 42088101,42175056）
