温州市历史暴雨时空分布及环流关联分析

Analysis of the Spatiotemporal Distribution and Circulation Correlations of Historical Rainstorms in Wenzhou

摘要: 本研究利用NCEP/NCAR逐日海平面气压场资料及国家地面观测站降水资料，采用Lamb-Jenkinson环流分型法，分析了温州市历史暴雨与大气环流的特征，并探讨了环流型与暴雨发生的关联。结果表明：温州暴雨日数呈西多东少的空间分布；夏季暴雨最为频发，冬季最少，季节差异显著；年暴雨日数在研究时段内无显著变化趋势。温州区域的主导环流为反气旋型(A)、反气旋性混合型(AE)和平直偏东型(E、NE)。年代际分析显示，研究期内A型环流出现频率显著下降；四季间环流型频率差异明显，且与季节内影响系统密切相关。反气旋型及其混合型环流(如AE、AN)诱发暴雨的能力极弱；平直气流型环流与暴雨发生的关系表现出显著的风向依赖性；在气旋型与偏东南风共同作用的环流配置下，温州地区出现暴雨的概率最高。

Abstract: Based on daily sea-level pressure field data from NCEP/NCAR and precipitation data from national surface weather stations, this study used the Lamb-Jenkinson method to analyze the characteristics of historical rainstorms and atmospheric circulation and to explore the relationship between the two in Wenzhou. The results show that rainstorms in Wenzhou are more frequent in the west than in the east; summer is the most frequent season for rainstorms, while winter sees very few, showing a marked difference; the annual number of rainstorm days has not changed significantly over time. The dominant circulation patterns in Wenzhou are anticyclonic types (A, AE) and directional types (E, NE). Interdecadal analysis shows a significant decline in the frequency of Type A circulation during the study period; there are relatively marked differences in the frequency of circulation types across the four seasons in Wenzhou, which are significantly related to intraseasonal influencing systems. Anticyclonic types (such as AE and AN) have extremely low potential to trigger rainstorms; the relationship between directional types and rainstorms exhibits significant wind‑direction dependence; the highest rainstorm probability occurs when low‑pressure systems combine with southeasterly winds.