Abstract:

Based on daily maximum temperature observations from 54 national meteorological stations in Liaoning during 1961-2023 and reanalysis data from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR), this study objectively identifies regional high temperature processes using established criteria, analyzes their spatiotemporal characteristics, and classifies the associated large-scale circulation patterns. A total of 24 regional high temperature events were identified during the study period, primarily affecting western Liaoning. The largest event impacted up to 55.56% of all stations. These events occurred between late May and mid-August, with mid-June showing the highest frequency. Most events lasted 3-4 days, accounting for 75% of the total. The frequency and spatial extent of regional high temperature events varied across decades, with fewer and less extensive events from the 1960s to the 1980s, and a notable increase in both frequency and coverage since the 1990s. Two primary circulation patterns were identified: warm high pressure ridge pattern (21 events) and zonal circulation pattern (3 events). In early and mid-summer, the warm high pressure ridge pattern dominated. In mid-summer, the frequency of the zonal circulation pattern increased with the northward shift of the Western Pacific subtropical high.

Key words: regional high temperature processes, Liaoning, climatic characteristics

摘要：

基于1961—2023年辽宁地区54个国家气象站逐日最高气温观测资料及美国国家环境预报中心/国家大气研究中心（National Centers for Environmental Prediction/National Center for Atmospheric Research，NCEP/NCAR）再分析数据，采用区域性高温过程的客观识别标准，对辽宁区域性高温过程进行识别与特征分析，并对其环流背景进行分型。结果表明，1961—2023年，辽宁共发生24次区域性高温过程，主要集中在西部地区，单次过程的最大影响范围可占全部监测站点的55.56%；高温过程最早始于5月下旬，最晚结束于8月中旬，其中以6月中旬发生次数最多；多数过程持续3~4 d，占总数的75%。不同年代区域性高温过程的发生频次和覆盖范围有所差异，表现为20世纪60—80年代过程偏少、范围较小，20世纪90年代起频次增多、影响范围扩大。造成辽宁区域性高温过程的环流形势主要分为2类：暖高压脊型（21次）和纬向环流型（3次）。初夏与盛夏，主要影响系统均为暖高压脊型；盛夏，随着西太平洋副热带高压北抬，纬向环流型出现频率有所上升。

关键词: 区域性高温过程, 辽宁, 气候特征