Spatiotemporal variability of extreme precipitation in north and south of the Qinling-Huaihe region and influencing factors during 1960-2013

Based on the monthly precipitation of a 0.5°×0.5° grid dataset and the daily precipitation observations of 135 meteorological stations released by the National Meteorological Information Center of China, this study analyzed the spatiotemporal variation of extreme precipitation in north and south of the Qinling- Huaihe region during 1960- 2013, using the methods of trend analysis, Sen + Mann- Kendall model, and correlation analysis.More specifically, we analyzed the relationship between ENSO and the observed extreme precipitation. The results are as follows:(1) the precipitation showed an increasing trend in the lower reach of the Yangtze River and a decreasing tendency in the other regions;(2) extreme precipitation analysis indicates a declining trend in rainy days and an increasing trend in precipitation intensity. The number of continuous drought events increased.Spatially, the regions with increasing intensity of extreme precipitation were mainly distributed in the QinlingBashan Mountains and the lower reaches of the Yangtze River and Yellow River, whereas there were more drought events in the Guanzhong Plain, Wushan Mountains, and Sichuan Basin;(3) Extreme precipitation had a close relationship with ENSO in the study region. In El Ni?o years, more precipitation was found in the spring but there was less precipitation in the summer and the whole year. In La Ni?a years, there was less precipitation in the spring and more precipitation in the autumn and the whole year. The responses of extreme precipitation events to El Ni?o exhibited spatial differences. Most of the regions with decreasing extreme precipitation in El Ni?o years were distributed in the lower reach of the Yellow River, the Guanzhong Plain and Qinling- Bashan Mountains, as well as the Sichuan Basin, while the region with increasing extreme precipitation was the Huaihe Plain. The lower reach of the Yangtze River and the Wushan Mountains showed no clear response to ENSO.