A 31-year trend of the hourly precipitation over South China and the underlying mechanisms

Abstract

On the basis of a newly developed intensive hourly observational precipitation dataset, the precipitation trend of South China was investigated. Results indicate that the hourly precipitation over South China featured a significant increasing trend, particularly for the extreme precipitation category. The trend is mainly due to the increasing frequency of the precipitation events. A possible mechanism accounting for this increasing trend was proposed: the global warming may be the original forcing for the trend, through its modulation on activities of the western Pacific subtropical high, but the low-level vorticity is the most important direct trigger.