Intraseasonal evolution and climatic characteristics of hourly precipitation during the rainy season in the Poyang Lake Basin, China

In the key flood control area of the Poyang Lake Basin (China), over 80% of annual precipitation is concentrated in the rainy season. This study investigated the intraseasonal evolution and climatic characteristics of precipitation during the rainy season in the Poyang Lake Basin under the background of climate change. On the basis of the precipitation pattern, the rainy season was divided into three stages: the spring rainy season, Meiyu season, and summer rainy season. Generally, total precipitation and precipitation hours showed no significant trends of change, whereas precipitation intensity had an obvious trend of increase. In the spring rainy season, the trend of total precipitation was downward but not significant; however, owing to substantial reduction in precipitation duration, precipitation intensity was enhanced significantly. In the Meiyu season (summer rainy season), total precipitation increased significantly because of increased precipitation duration (precipitation intensity). The spatial distributions of total precipitation in the spring rainy season and Meiyu season were similar, i.e., precipitation occurred mostly in the east and less in the west; however, the spatial distributions of the change trends were opposite. In the summer rainy season, precipitation was concentrated primarily in the surrounding mountainous areas.