西安市汛期降雨特征的多尺度分析及未来趋势预测

Analysis on the Precipitation Characteristics in Multiple Scales and Prediction of Future Trend in flood season in Xi'an

利用1951—2013年汛期降雨量（日）资料,采用线性回归、Mann-Kendall检验、小波分析和R/S分析等方法,对西安市汛期降雨特征及未来演变趋势进行研究。结果表明：（1）汛期总降雨量、总降雨日、小雨量和小雨日均表现出减少趋势,倾向率为-1.9 mm/10 a,-0.3 d/10 a,-2.9 mm/10 a和-0.4 d/10 a,均在20世纪60年代和21世纪前10年出现减少和增加的突变。中雨和大雨及以上等级降雨量（日）表现出微弱增加趋势。（2）各等级降雨量和降雨日的周期震荡较一致,小雨、大雨及以上和总降雨量（日）以年代际震荡（20~25年）为主,中雨以年际震荡（3~4年）为主。未来小雨、中雨和总降雨量（日）继续减少,大雨及以上降雨量（日）短期内继续微弱增加,2015年后减少。（3）综合利用小波分析和Hurst指数试验可为未来降雨气候变化趋势做出全面诊断和预测。

Based on the data of precipitation and the days of precipitation in flood season in Xi＇an from 1951 to 2013, the precipitation characteristics in Xi＇ an in recent 63 years was analyzed with linear regression, Mann-Kendall detection, wavelet analysis and R/S analysis method. The conclusions are as follows： （1） total precipitation, days of total precipitation, light rain, days of light rain all showed a decreasing trend, with a decreasing rate of-1.9 mm/10 a,- 0.3 d/10 a,- 2.9 ram/10 a and-0.4 d/10 a respectively, and reduced suddenly in the 1960s, and increased suddenly in the 2010s; moderate rain, days of moderate rain, heavy rain and the above, days of heavy rain and the above increased slightly; （2） for the same grade, precipitation and the days of precipitation showed consistent periodic oscillation; as for light rain, heavy rain and the above, and the total rain, precipitation and the days of precipitation all showed 20-25 year decadal periodic oscillation, while moderate rain with 3-4 year inter-annual periodic oscillation; we predict that, precipitation and the days of precipitation of light rain, moderate rain and the total rain will continue decreasing, heavy rain and the above will increase slightly, and begin to decrease after 2015; （3） future trend of precipitation characteristics will be diagnosed and predicted comprehensively with wavelet analysis and Hurst index experiment.