摘要:在对34年华南暖区暴雨的筛选和客观分类研究的基础上,继续深入研究不同类型暖区暴雨的环流特征与对流发生环境变量特征的异同。主要结果如下:大部分切变线型、低涡型和回流型暖区暴雨个例的环境场斜压性较强,其中回流型暖区暴雨在关键区斜压性最强,而南风型暖区暴雨个例的环境场斜压性相对较弱;所有类型暖区暴雨发生时对流层中高层的中纬度基本为平直西风气流控制,降水区主要位于西风带短波槽槽前,低层均有低空急流的影响。各类暖区暴雨的主要差异在于高层南亚高压、中层短波槽和副热带高压的位置和强度差异以及低层低空急流的位置、强度、风向和水汽输送条件的不同。切变线型暖区暴雨发生时0~3 km垂直风切变最强,低涡型暖区暴雨对流有效位能最大,两类南风型暖区暴雨的动力和热力强迫都较弱,对其发生发展机理需要开展更深入研究。
关键词:暖区暴雨/
环流特征/
斜压性/
低涡/
回流
Abstract:Based on the objective classification of warm-sector heavy rainfall events over South China, a synoptic analysis is used to study the similarities and differences between the circulation characteristics and environmental variables for the different types of warm-sector rainfall events. Results reveal that most of the shear line type, vortex type, and backflow type warm-sector rainfall events have strong baroclinic environments, with the backflow type being the strongest and the south wind type being relatively weak. All warm-sector rainfall events are controlled by the horizontal westerly airflow at the middle latitudinal area when they occurred. The precipitation area is mainly located in front of the short-wave trough and is affected by the low-level jet at lower layers. The main differences between the different types of warm-sector rainfall events are the location and intensity of the South Asia high, middle-level wave trough, western Pacific subtropical high, and low-level jet, and the difference between the wind direction and water vapor condition. Different types of warm-sector rainfall events exhibit differences between the environmental variables. The shear line warm-sector rainfall has the strongest vertical wind shear (0–3 km) in five types, and the vortex type has the largest convection effective potential energy. The dynamic and thermal forces of the two types of southerly warm-sector rainfall events are the weakest among all types of warm-sector rainfall events. The mechanism of its occurrence and development needs to be further studied.
Key words:Warm-sector heavy rainfall/
Synoptic circulation characteristic/
Environmental variable/
Vortex/
Backflow
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