Analysis of Spatial and Temporal Distribution Characteristics of Hail Disaster in Lijiang City

通过对丽江市4个国家气象站50年降雹日数及近年丽江雷达回波的统计与分析，揭示丽江市冰雹灾害时空分布特征：(1) 丽江市年均发生冰雹4.62站次，丽江坝区最多，年均1.88次，华坪县最少，年均0.3次；(2) 丽江市具有海拔越高、冰雹越多，及西北部多于东南部的特点；(3) 丽江冰雹易出现于春夏两季，以5、6月份为最多，各测站年降雹日数变化呈现不一致性，永胜站呈缓慢增加趋势，其它各站呈减少趋势，宁蒗站减少得最快，变化倾向率为−0.26次/10a；(4) 近年监测结果表明：丽江冰雹均发生在13~24时的11个时次内，以15~20时为主要时段；丽江冰雹可分为单点型和系统型，其发生和移动具有一定的规律。Through statistical analysis of hail days over 50 years at four national meteorological stations in Lijiang City and recent radar echo data, this study reveals the spatiotemporal distribution characteristics of hail disasters in Lijiang: (1) The annual average hail occurrence is 4.62 station-times, with Lijiang Basin having the highest frequency (1.88 times/year) and Huaping County the lowest (0.3 times/year). (2) Hail frequency increases with elevation and is more prevalent in northwestern regions than southeastern areas. (3) Hail predominantly occurs in spring and summer, peaking in May and June. Annual hail day trends vary across stations: Yongsheng shows a slow increasing trend, while other stations exhibit decreasing trends, with Ninglang decreasing most rapidly (−0.26 times/10a). (4) Recent monitoring indicates that hail events occur exclusively between 13:00~24:00 (11 hourly intervals), primarily during 15:00~20:00. Lijiang hail can be classified into single-point and systemic types, demonstrating certain formation and movement patterns.