1960―2017年秦岭南北地区降雨侵蚀力的时空变化特征研究

基于秦岭南北地区1960―2017年47个气象站点逐日降雨资料，根据章文波提出的日降雨侵蚀力模型估算降雨侵蚀力，并采用气候倾向率、反距离权重插值及Mann-Mendal突变检验等方法分析秦岭南北地区近58 a年均降雨侵蚀力与不同量级降雨侵蚀力的时空变化特征。 结果表明：（1） 1960―2017年秦岭南北地区年均降雨侵蚀力与不同雨量产生的降雨侵蚀力均呈由南向北递减的特征。（2）近58 a，秦岭南北地区年均降雨侵蚀力、大雨与暴雨侵蚀力年际变化呈增长趋势，未通过突变检测；中雨侵蚀力呈减弱趋势，在1972年发生突变且在2007年后达到显著；其中秦岭以北年均降雨侵蚀力、中雨侵蚀力、暴雨侵蚀力均呈下降趋势，且年际波动程度较大，秦岭以南年均降雨侵蚀力及大雨、暴雨侵蚀力均呈上升趋势。（3）秦岭南北地区年均降雨侵蚀力变化趋势空间差异显著，明显增长区集中于汉中盆地与巴巫谷地，减少区集中于西部嘉陵江、秦岭以北汾河入黄河交界、汉水流域两湖平原；且不同量级侵蚀力呈增长趋势的面积大小依次为大雨侵蚀力>暴雨侵蚀力>中雨侵蚀力。

Temporal and spatial variations of rainfall erosivity in the northern and southern regions of Qinling mountains from 1960 to 2017

Based on the daily rainfall data of 47 meteorological sites in the northern and southern regions of Qinling mountains，the annual average rainfall erosivity of the northern and southern regions of Qinling mountains is calculated following the rainfall erosivity model proposed by ZHANG which was set up on the basis of daily rainfall. The spatio-temporal characteristics of rainfall erosivity of different rainfalls in the study are analyzed by adopting the climate trend rate, inverse distance weight interpolation and Mann-Mendal mutation test. It shows: (1)The annual average rainfall erosivity due to different rainfalls in the concerned area from 1960 to 2017 exhibits a decreasing feature from south to north. (2)The interannual changes of the annual average rainfall erosivity, the erosivity due to rainstorm and heavy rain in the past 58 years shows an increasing trend, which fails to be detected by mutations. The erosivity due to moderate rain shows a decreasing trend. The mutation occurred in 1972, it reached a significant value after 2007. The annual average rainfall erosivity and storm erosivity in the northern region of the Qinling mountains exhibits a downward trend, and the degree of interannual fluctuations is relatively large. However, these parameters in the southern regions of the Qinling mountains demonstrates an opposite trend. (3)The average annual rainfall erosivity in the study shows a significant spatial variation. The obvious growth areas are concentrated in the Hanzhong basin and the Bawu valley. The reduction areas are concentrated in the western Jialing River , the junction of the Fen River and the Yellow River, as well as the two lake plains. The size of the area where the erosivity showed a growth trend presents a correspondence with the amount of the rainfall: heavy rainfall>rainstorm >moderate rain.