甘肃省陇东地区极端降水的时空特征

为阐明甘肃省陇东地区极端降水的变化规律,利用该地区13个气象台站1961~2015年的逐日降水资料,应用超门限峰值法、反距离加权法、线性倾向估计法、滑动平均法、Mann-Kendall突变分析法、复值Morlet小波分析法研究极端降水的时空变化特征。结果表明,陇东地区各站第95百分位极端降水阈值在27.8mm附近变化,即可以大雨事件作为极端降水事件进行监测;极端降水指数主要表现为从南向北递减的趋势,极端降水事件对环县和崆峒的影响较小;极端降水事件虽然在总量、强度上表现为减小趋势,但其发生频次及对总降水的贡献率逐渐增强;极端降水总量和极端降水强度周期变化均在21年左右能量最强,而极端降水频次和极端降水贡献率周期变化分别在28、5年左右能量最强。

Temporal and Spatial Characteristics of Extreme Precipitation in Longdong Region

Based on the daily precipitation data of 13 meteorological stations in Longdong area of Gansu Province from 1961 to 2015, the temporal and spatial variation characteristics of extreme precipitation are studied by using the methods of exceeding threshold peak value, inverse distance weighting, linear tendency estimation, moving average, Mann-Kendall catastrophe analysis and complex Morlet wavelet analysis. The results show that the extreme precipitation threshold at 95% quantile in Longdong area varies near 27.8 mm, which means that heavy rain events can be used as extreme precipitation events to be monitored; The extreme precipitation index mainly shows a decreasing trend from south to north, and the extreme precipitation events have little impact on Huanxian and Kongtong; Although the extreme precipitation events show a decreasing trend in the total amount and intensity, the frequency of occurrence and the contribution rate of the total amount precipitation increase gradually. The periodic variation of the total and intensity of extreme precipitation is the strongest in 21 a, while the periodic variation of frequency and intensity of extreme precipitation is the strongest in 28 a and 5 a, respectively.