Moisture sources for the weather pattern classified extreme precipitation in the first rainy season over South China. (1st March 2022)

• Record Type: Journal Article
• Authors: Xin, Fan; Peng, Dongdong; Liu, Run; Liu, Shaw Chen
• Is Part Of: International journal of climatology. Volume 42:Number 11(2022)
• Page Start: 6027
• Page End: 6041
• Publication Date: 2022-03-01
• Subjects: extreme precipitation -- FLEXPART -- K‐means clustering -- moisture source -- South China; Climatology -- Periodicals; Climat -- Périodiques; Climatologie -- Périodiques; 551.605
• DOI: 10.1002/joc.7576
• Languages: English
• ISSNs: 0899-8418

Abstract

Abstract: Moisture transport, associated with moisture sources and synoptic‐scale weather conditions, is a key dynamic process of precipitation events. Using the K ‐means clustering method and the FLEXPART Lagrangian particle dispersion model, this paper investigates moisture contributions from different source regions to extreme precipitation in the first rainy season (hereafter FRS) over South China. In average, land regions contribute more to the FRS extreme precipitation over South China than the ocean regions. The main source regions are Southeast Asia (22.7%), South China (17.2%), the South China Sea (14.3%), and the Bay of Bengal (8.3%). Extreme precipitation events are classified into three types by the K ‐means clustering based on 850 hPa geopotential height, which are all characterized by an anomalous low‐pressure system over South China with varying intensity and locations. The distribution of geopotential height anomaly for Type I (30.3%) is characterized the low trough extending from Japan to South China, while Type II (42.5%) and Type III (27.2%) are characterized by "west negative–east positive" and "north positive–south negative" patterns over East Asia with anomalous cyclone over South China, respectively. The much larger contribution of land sources than ocean regions are mainly concentrated in Type I and Type III, of which the contribution from each source region is similar. Ocean sources play a more important role in Type II and are mainly from the Indian Ocean (16.2%) associated with the onset of South China Sea summer monsoon. Abstract : The weather patterns for first rainy season extreme precipitation over South China are classified into three types, which are all characterized by a local anomalous cyclone but with different locations of its centre and intensity. Land sources contribute much more than the ocean regions to Type I and Type III. The contribution of ocean regions for Type II is larger than that of the other two types, which is mainly contributed by the Indian Ocean associated with the onset of the South China Sea summer monsoon.