西安市极端降雨时间演变特征分析

全球气候变化导致城市洪涝灾害频发，极端降雨具有历时短、成灾快的特点，是造成城市内涝的主要原因，研究极端降雨的变化趋势，可为城市应对内涝提供参考。为分析西安市极端降雨事件的时间演变特征，采用滑动平均、线性回归、M-K突变性检验和Hurst指数分析等方法对西安市1990—2020年的降雨资料进行分析，得出西安市近30年降雨事件随时间的变化特征，并对未来变化趋势进行预测分析。结果表明:1）西安市年降雨量无明显变化趋势，但极端降雨量以每10年29 mm的速率呈增加趋势，并且在2002年突变性增加；2）极端降雨频次以每10年0.85次的速率呈增加趋势，并且在2014年突变性增加；3）极端降雨量和极端降雨频次的Hurst指数分别为0.974和0.893，具有较强的持续性，这表明两者变化趋势与过去相一致，未来西安市的极端降雨事件会呈持续增加趋势。

TEMPORAL VARIATION CHARACTERISTICS OF PRECIPITATION EXTREMES IN XI'AN

Global climate variation leads to frequent urban flood disasters. Extreme rainfall has the characteristics of short duration and rapid disaster, which is the major cause of urban inundation. The study on the changing trend of extreme rainfall can provide a reference for cities to deal with inundation. To analyze the temporal evolution characteristics of extreme rainfall events in Xi'an, this paper analyzed the rainfall data of Xi'an from 1990 to 2020 by using the methods of moving average, linear regression, M-K mutation test, and Hurst index analysis. After that, the change characteristics of rainfall events in Xi'an over the past 30 years were obtained, and the future change trend was predicted and analyzed. The results showed that:1) there was no obvious change trend of annual rainfall in Xi'an, however, the extreme rainfall showed an increasing trend at the rate of 29 mm/10 a, and the trend had an increasing mutation in 2002; 2) the frequency of extreme rainfall showed an increasing trend of 0.85 times/10 a, however, the frequency of extreme rainfall had an increasing mutation in 2014; 3) the H values of extreme rainfall and extreme rainfall frequency were 0.974 and 0.893 respectively, and both had strong sustainability. This showed that the change trends of both were consistent with the past, and the extreme rainfall events in Xi'an would continue to increase in the future.