浙江东部两次极端台风暴雨的水汽特征研究

Study on Water Vapor Characteristics of Two Extreme Typhoon Rainstorms in Eastern Zhejiang Province

摘要: 本文利用自动站资料、ERA5 (0.25˚ × 0.25˚)逐时再分析等资料，基于天气学和诊断方法对2013年23号台风“菲特”、2019年09号台风“利奇马”引发浙江东部极端暴雨过程的水汽输送特征进行综合分析。结果表明：(1) 浙江东部极端台风暴雨过程通常对应水汽通道的长时间稳定维持，为暴雨发生发展提供源源不断的水汽条件。并且一些情况下水汽通道存在多条。(2) 造成浙江东部极端台风暴雨过程往往洋面上存在多个台风相互作用，多台风带来的水汽更为充沛。(3) Hysplit三维轨迹能更直观立体反应水汽来源，其与水汽输送路径分析结论基本一致。浙江省东部极端台风暴雨的水汽净输入边界往往为东边界。(4) 暴雨发生前、发生时，水汽通量散度强负中心与强暴雨区对应很好，并且水汽通量散度负值中心的变化往往对应降水的减弱或暴雨带位置的变化。(5) 极端台风降水时段近地面往往稳定存在急流输送水汽，并且降水增强伴随急流增强；站点上空为整层饱和区，水汽条件极佳。

Abstract: Based on the meteorological and diagnostic methods, this paper comprehensively analyzes the water vapor transport characteristics of extreme rainstorm caused by Severe Typhoon Fitow and Super Typhoon Lekimain in eastern Zhejiang Province by using automatic station data and hourly reanalysis of ERA5 (0.25˚ × 0.25˚). (1) The extreme typhoon rainstorm process in eastern Zhejiang usually corresponds to the long-term stable maintenance of water vapor channel, providing continuous water vapor conditions for the occurrence and development of rainstorm. And in some extreme cases, there are several water vapor channels. (2) In the process of extreme typhoon rainstorm in eastern Zhejiang, there are often several typhoons interacting on the ocean surface, which bring more abundant water vapor. (3) The three-dimensional trajectory of Hysplit can more intuitively reflect the water vapor source, which is basically consistent with the analysis conclusion of water vapor transport path. The net water vapor input boundary of extreme typhoon rainstorm in eastern Zhejiang Province is usually the eastern boundary. (4) Before and during the rainstorm, the strong negative center of Moisture Flux Convergence corresponds well to the severe rain area, and the change of the negative center of Moisture Flux Convergence often corresponds to the weakening of precipitation or the change of the location of the rainstorm zone. (5) During the extreme typhoon precipitation period, water vapor is usually transported by the jet stream near the surface, and the increase of precipitation is accompanied by the increase of the jet stream. The whole layer is saturated above the station, and the water vapor condition is excellent.