Comparison of the physical processes underlying heavy and light rain variations: insight from spring precipitation over Southern China

• Published in: Climate dynamics Vol. 62; no. 10; pp. 9951 - 9969
• Main Authors: Zeng, Zixuan, Sun, Jianqi, He, Shengping
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.10.2024; Springer Nature B.V
• Subjects: Air transport; Air transportation; Aircraft; Anticyclones; Atmospheric conditions; Atmospheric precipitations; Baroclinity; Climatology; Cooling; Cyclones; Earth and Environmental Science; Earth Sciences; El Nino; El Nino phenomena; Geophysics/Geodesy; Heavy rainfall; Lakes; Light; Low clouds; Moisture; Oceanography; Original Article; Precipitation; Rain; Rainfall; Relative humidity; Sea surface temperature; Southern Oscillation; Spring; Spring (season); Spring precipitation; Surface temperature; Troposphere; Variation; Lake Balkhash; China; El Niño-Southern Oscillation (ENSO); Extreme consecutive dry days; Light rain; Heavy rain; North Atlantic sea surface temperature; Total precipitation amount
• ISSN: 0930-7575; 1432-0894
• DOI: 10.1007/s00382-024-07416-7

This study compares the physical processes responsible for the heavy and light rain variations from the perspective of spring precipitation over Southern China. The results indicate that, heavy rain variation has a closer connection with the western North Pacific anticyclone. Intensified western North Pacific anticyclone and associated warm and humid air transport, coupled with intensified East Asian subtropical jet, favor significant moisture convergence and enhanced convective feedback over the key region, which causes increased heavy rain rather than light rain over there. In comparison, light rain variation shows a close relationship with the anomalous low over Lake Balkhash, which causes lower-tropospheric cyclone over the key region. On the one hand, anomalous cyclone favors lower-tropospheric cooling; concurred with cyclone-induced increased moisture, the lower-tropospheric relative humidity increases over there. On the other hand, the lower-tropospheric cooling center shifts northward with height and causes enhanced atmospheric baroclinity over there. Such atmospheric conditions are conducive to the occurrence of low cloud and more light rain. In addition, intensified East Asian subtropical jet associated with Lake Balkhash anomalous low also provides favorable dynamic lifting condition. Moreover, heavy and light rain variations are more related to El Niño-Southern Oscillation and North Atlantic horseshoe sea surface temperature in preceding winter, respectively. In addition, heavy rain shows a closer relationship with total precipitation amount variation, whereas light rain is more related to extreme consecutive dry days variation.