Resumen
The Dongting Lake Basin (DTLB) of China is a flood prone area. Knowledge of the spatiotemporal characteristics and risks of precipitation extremes is essential for flood mitigation. Based on the precipitation amount (R), precipitation intensity (Ri), max 1 day precipitation amount (Rx1) and max 5 day precipitation amount (Rx5), this study analyzed the spatial-temporal patterns, risks and investigated the influences of the precipitation extremes at seasonal scale. The distributed high values of R, Ri, Rx1, Rx5 and their 5-year return levels (R5, Ri5, Rx15, Rx55) indicated high flood risks in the eastern and northern parts of the basin, and the general upward trends of these indices suggested increasing flood risks, except for some areas in southwestern part in spring and autumn. The precipitation extremes were related to the topographic and circulation factors, within which the latter might have greater roles. Furthermore, the trend directions of the 5-year return levels (R5, Ri5, Rx15, Rx55) were not always the same as the initial indices (R, Ri, Rx1, Rx5), suggesting that overall decreasing (increasing) precipitation extremes do not always represent decreasing (increasing) risks of floods. Hence, policy makers should pay more attention to the risks of precipitation extremes rather than their overall tendencies.