Changes in the Intensity of Tropical-Cyclone-Induced Precipitation along the Southeastern Coast of China between 1978 and 2007

Changes in the intensity of tropical-cyclone-induced precipitation and its contribution to variations in the total late summer (July-August) precipitation in coastal southeastern China were investigated using daily rain gauge data and tropical cyclone best-track data for 1978-2007. An increase in tropical-cyclone-induced precipitation was the main reason for the increase in late summer precipitation along the southeastern coast of China in the last 30 years. The intensity of tropical-cyclone-induced rainfall both along the southeastern coast and inland increased significantly, while the rainfall frequency changed little. The mean distance between the rain gauge and the center of the tropical cyclone was reduced in inland. The frequency of rainfall caused by nearby tropical cyclones appeared to have increased significantly and to have been the main source of the increase in tropical-cyclone-induced precipitation intensity. At the same time, in coastal southeastern China (where the precipitation induced by nearby tropical cyclones did not change much), there was a general increase in the intensity of tropical cyclone precipitation that was not affected by the distance between the tropical cyclone and the rain gauge. This led to an increase in the mean intensity of the tropical cyclone induced precipitation measured at each rain gauge. The changes in the spatial distribution of the mean frequency of tropical cyclones in late summer over the last 30 years showed that the number of tropical cyclones that passed over the coast of China changed little, but the number of tropical cyclones passing through Fujian increased. The frequency of tropical cyclones passing over inland areas increased because of the increase in the number of cyclones and a decrease in the translation velocities of tropical cyclones passing through, which is consistent with the significant increase seen in the tropical-cyclone-induced precipitation.