近50年平凉黄土高原沟壑区气温和降水变化趋势分析

Analysis of the Past 50 Years' Change Trend of Temperature and Precipitation in Pingliang Gully Region of Loess Plateau

[目的]研究平凉黄土高原沟壑区气温和降水变化,全面了解当地气候变化特点和未来发展趋势。[方法]采用线性倾向估计法对平凉黄土高原沟壑区近50年的年平均气温和年降水量的变化特点进行分析,用累积距平法和Mann-Kendall法对气候突变进行分析检测,并用重标极差(R/S)法对其未来气候变化趋势进行分析。[结果]近50年平凉黄土高原沟壑区气温呈上升趋势,气温变化率为0.26℃/10年,降水呈减少趋势,降水变化率为-20.2 mm/10年;气温的Hurst指数为0.90,降水量的Hurst指数为0.62,预示未来气温上升和降水减少的趋势还将持续;气温的突变发生在1997年,而年降水量的突变发生在1991年,二者的突变时间不同步。[结论]以气温升高降水减少为主要特征的气候变化将对平凉黄土高原沟壑区农业生产产生不利影响。

[ Objective ] The character of climatic variation and its future trend in Pingliang Gully Region of Loess Plateau were completely understood through the research on the change of temperature and precipitation in the region. [ Method] The variation character of annual average temperature and precipitation of past 50 years in the region was analyzed with the method of linear trend evaluation. The abrupt change of climatic factor was tested with the method of cumulative departure and Mann-Kendall. And the trend of its future change was analyzed with R/S. [ Results] The results showed that annual temperature in the Pingliang Gully Region of Loess Plateau was increasing in last 50 years with a change rate of 0.26 ℃ per a decade year and annual precipitation was declining with a change rate of 20, 2 mm per a decade year. The Hurst index of temperature was 0.90 and the Hurst index of precipitation was 0.62, which indicated that the trends would be going on in the future. The point of abrupt change of temperature happened in 1997, while annual precipitation, in 1991 and the abrupt change of temperature and precipitation was not occurring simultaneously.[ Conclusion] The variation of the raising of temperature and the reduction of precipitation in the region could cause the bad effect on agricultural production.