Zhao Xingkai, Li Zengyao, Zhu Qingke
School of soil and water conservation, Beijing Forestry University, Beijing, 100083, China.
Sci Rep. 2017 Aug 14;7(1):8048. doi: 10.1038/s41598-017-08600-y.
Precipitation plays an important and crucial role in processes in the water-wind erosion crisscross region of the Loess Plateau than in other parts of the region. We analyzed precipitation data and standardized precipitation index (SPI) at 14 representative synoptic stations from 1958 to 2015 used trend-free prewhitening, linear trend estimation, Spearman's rho test, the Mann-Kendall trend test, the Mann-Kendall abrupt change test and rescaled range analysis. The following conclusions were drawn. First, the analysis of monthly precipitation at all stations suggested that precipitation during the rainy season (July, August, September), especially rain in July and August, exhibited a general decreasing trend, while both increasing and decreasing trends were observed in other months. Moreover, the annual precipitation of all stations continued to exhibit decreasing trends except Wuzhai. Erosive rainfall frequency in the rainy season and the annual scale was weakly reduced but erosive force of single rainfall has been enhanced. Second, the SPI exhibited different increasing degrees in winter, while decreasing trends were observed in other seasons. Additionally, the annual-scale SPI at most stations exhibited a stable and sustained downward trend. Therefore, this region is currently associated with a drought trend, and the drought degree will likely continue to increase.
与黄土高原水蚀风蚀交错区的其他地区相比，降水在该区域的过程中发挥着重要且关键的作用。我们分析了1958年至2015年期间14个代表性气象站的降水数据和标准化降水指数（SPI），采用了无趋势预白化、线性趋势估计、斯皮尔曼秩相关检验、曼-肯德尔趋势检验、曼-肯德尔突变检验和重标极差分析。得出了以下结论。首先，对所有站点月降水量的分析表明，雨季（7月、8月、9月）的降水量，尤其是7月和8月的降雨，总体呈下降趋势，而其他月份则呈现出上升和下降两种趋势。此外，除五寨外，所有站点的年降水量持续呈下降趋势。雨季和年尺度上的侵蚀性降雨频率略有降低，但单次降雨的侵蚀力有所增强。其次，SPI在冬季呈现出不同程度的上升，而在其他季节则呈下降趋势。此外，大多数站点的年尺度SPI呈现出稳定且持续的下降趋势。因此，该地区目前正处于干旱趋势，干旱程度可能会继续加剧。
