Analysis on Variations of Heavy Rainfall Events in Loess Plateau during 1980–2017, China

Variations among the different precipitation intensities can be quite large. Analysis of annual precipitation data without the consideration of different precipitation intensities, especially the heavy precipitation events, may lead to misinterpretation of precipitation variation. In order to make clear the spatial-temporal behaviors of heavy precipitation events in recent years in Loess Plateau. Daily precipitation recorded at 161 precipitation stations between 1980 and 2017 were selected. Nonparametric Mann-Kendall test was employed to test the changing trend of precipitation. Results showed that the spatial distribution of heavy precipitation events can be quite different for the entire Loess Plateau. The contribution of heavy precipitation to the annual total precipitation is approximately 43~52%. The amount and days for the heavy precipitation both increased for the most areas of Loess Plateau in recent 38 years. Moreover, Mann-Kendall test shows a pronounced change toward more precipitation in the northern Loess Plateau, and higher intensity in southern Loess Plateau. Higher risk exhibited in areas of northern and southern Loess Plateau, which should raise concern. More soil and water conservation measures and practices could be implemented to reduce the negative impacts of flood or erosion events.