Precipitation extremes in a karst region: a case study in the Guizhou province, southwest China

We analyzed the changing properties of precipitation extremes in the Guizhou province, a region of typical karst geomorphology in China. Precipitation extremes were defined by the largest 1- and 5-day precipitation total. Trends of precipitation extremes were detected by using Mann-Kendall trend test technique. Besides, we also investigated moisture flux variations based on the National Centers for Environmental Prediction and the National Center for Atmospheric Research reanalysis dataset with the aim to further explore the possible causes behind the changes in precipitation extremes. The results of this study indicated that: (1) Although the changes in precipitation extremes at most of the stations were not significant, enhanced precipitation extremes were still detected after the early 1990s mainly in the middle and west parts of the Guizhou province; (2) In winter, east and south parts of the Guizhou province were characterized by increasing precipitation extremes; In summer, enhanced precipitation extremes were observed mainly in the middle and east parts of the Guizhou province; (3) A significant increase of moisture flux was observed after the 1990s when compared to that before the 1990s. Cumulative departure analysis results of moisture flux and precipitation extremes confirmed the influences of moisture flux on the variations of precipitation extremes in the study region. This study clarified the changes of weather extremes and their linkages with large-scale atmospheric circulation in the karst region of China, which will definitely enhance human mitigation to natural hazards in the fragile ecological environment under the influences of changing climate.