Effects of typhoon activities on extreme precipitation in coastal areas of China

Based on gridded daily precipitation data and the China Meteorological Administration typhoon best-track dataset from 1961 to 2020, this study presents an evaluation of the contribution of typhoons to extreme precipitation in coastal areas of China. Specifically, both mixed and single Metastatistical Extreme Value (MEV) models are devised to evaluate the effects of typhoons on the probability distribution of extreme precipitation amounts. The related influencing factors are explored by correlation tests and four case study watersheds are selected to showcase the effects of typhoons. The results show that typhoons make significant contribution to high-return-period extreme precipitation in coastal and some nearby inland areas of China. The mixed Metastatistical extreme value distribution, which takes into account the distribution of typhoon precipitation, can better formulate the probability of extreme precipitation. The relative errors between the estimated precipitation quantiles of mixed and single MEV tend to be larger in coastal areas than in inland areas, and also be larger in northern coastal areas than in southern sub-regions. Overall, the contribution of typhoons to extreme precipitation and the differences of average precipitation between typhoon-induced and non-typhoon-induced events are important influencing factors on the distribution of the probability of extreme precipitation in coastal areas of China.