• 研究论文 •

### 江淮流域梅雨过程识别及梅雨期分级降水时空特征

1. 1.水利部水文气象灾害机理与预警重点实验室，南京信息工程大学，南京 210044
2.南京信息工程大学水文与水资源工程学院，南京 210044
3.淮阴师范学院城市与环境学院，江苏 淮安 223300
• 收稿日期:2022-05-26 修回日期:2022-08-24 出版日期:2023-01-28 发布日期:2023-03-28
• 通讯作者: *杨秀芹(1981— )，女，山东聊城人，博士，副教授，硕士生导师，研究方向为流域水文气候与水资源规划与管理。E-mail: young_sd@nuist.edu.cn
• 作者简介:姚飛(1993— )，男，四川攀枝花人，硕士生，研究方向为流域水文气候与水资源规划与管理。E-mail: yaofei@nuist.edu.cn
• 基金资助:
国家自然科学基金项目(41907384)

### Identification of Meiyu process and spatiotemporal characteristics of different precipitation levels during the Meiyu period over the Yangtze-Huai River Basin

YAO Fei1,2(), YANG Xiuqin1,2,*(), LIU Mujia1,2, ZHANG Yuqing3, LI Hua1,2

1. 1. Key Laboratory of Hydrometeorological Disaster Mechanism and Warning of Ministry of Water Resources, Nanjing University of Information Science and Technology, Nanjing 210044, China
2. School of Hydrology and Water Resources, Nanjing University of Information Science and Technology, Nanjing 210044, China
3. School of Urban and Environmental Sciences, Huaiyin Normal University, Huai'an 223300, Jiangsu, China
• Received:2022-05-26 Revised:2022-08-24 Online:2023-01-28 Published:2023-03-28
• Supported by:
National Natural Science Foundation of China(41907384)

Abstract:

The spatiotemporal characteristics of Meiyu intensity index and different precipitation levels during the Meiyu period over the Yangtze-Huai River Basin are still unclear during recent 60 years under global climate change. This study used observed daily precipitation and temperature data from 239 meteorological stations over the Yangtze-Huai River basin from 1961 to 2020 combined with NCEP/NCAR reanalysis data to identify the Meiyu process and investigate the spatiotemporal characteristics of Meiyu intensity index, the number of rainy days, precipitation amount, precipitation incidence rate, and precipitation contribution rate of different precipitation levels during the Meiyu period, and calculate the contribution rate of urbanization to heavy precipitation indices during the Meiyu period. It aimed to provide references for early warning of rainstorm and flood events, flood and drought disaster prevention, and water resources regulation in the Yangtze-Huai River Basin during the Meiyu Period. The research results show that: The average Meiyu onset date and ending date were the earliest in area I (Jiangnan area), followed by area II (middle and lower reaches of the Yangtze River) and area III (Jianghuai area), and the length of the Meiyu period was 30 days, 30 days, and 24 days respectively. There was no obvious trend for onset date, ending date, and length of the Meiyu period. The average Meiyu rain intensity in area I was the highest, at 367.6 mm, followed by area II at 298.4 mm and area III at 253.5 mm; the Meiyu rain intensity index in area II showed a significant increasing trend in recent 60 years, and the average Meiyu intensity index was the highest in area Ⅱ. Violent Meiyu are most likely to occur in area II, and the inter-annual variation of the Meiyu intensity index was the largest in area III. Meiyu precipitation amount in the central part of areas Ⅰ and Ⅱ was relatively high, with the highest number of rainy days in area Ⅰ, followed by area Ⅱ and the lowest was found in area Ⅲ. During the Meiyu period, the number of light rain days was the largest and the incidence of precipitation was the highest, while the corresponding indices of moderate rain, heavy rain, and rainstorm decreased in turn. The trend of light rain days and moderate rain days was not obvious for most stations, but the number of heavy rain days and rainstorm days in the central and eastern parts of area II increased significantly. The trend of the incidence of heavy rain and rainstorm was not obvious for most stations, but the incidence of light rain and moderate rain for many sites in area II decreased significantly, which is the reason for the significant decrease of the incidence of precipitation during the Meiyu period in eastern area Ⅱ. Rainstorm amount accounted for the largest proportion of precipitation during the Meiyu period, the contribution rate of rainstorm was also the largest, and heavy rain, moderate rain, and light rain decreased in turn. The significant increasing trend of heavy rain and rainstorm precipitation at the eastern stations in areas I and II is the reason for the significant increasing trend of Meiyu precipitation in this area. The trend of precipitation contribution rates of different magnitudes of precipitation was not obvious for most stations, and only 17 stations in the central and eastern parts of area II showed a significant decreasing trend of the contribution rates of light rain and moderate rain. Urbanization aggravates the increasing trend of heavy precipitation, and the contribution rate of urbanization to R95P and R99P was 10.59% and 17.39%, respectively.