宁夏风蚀气候侵蚀力时空演变及影响因素分析

目的]揭示宁夏回族自治区风蚀气候侵蚀力(C值)的时空演变特征，阐明宁夏气候对风蚀的影响及因素，进而为宁夏风蚀评估提供科学依据。方法]基于宁夏及周边气象站1965—2019年的观测数据，根据FAO风蚀气候侵蚀力计算公式，利用Mann-Kendall趋势检验、Pettitt突变点检验、Morlet小波分析及随机森林等方法，开展了宁夏风蚀气候侵蚀力时空演变及影响因素的研究。结果](1)宁夏多年平均C值为23.8,在年尺度和季节尺度上呈现可持续的显著减少趋势，且春冬季高、夏秋季低。(2)多年平均C值在空间上呈现中北部高、南部低的分布，显著减少的站点共8个，且均呈现可持续性。(3)除夏季尺度外，其他季节尺度和年尺度的C值均在2003年前后发生显著突变，且均存在一个30 a左右的主周期。(4)影响C值最主要的因子是风速，其次是降水量、相对湿度、热力因子、太平洋年代际振荡指数。结论]宁夏属于干旱半干旱地区气候侵蚀力较弱的区域，风速是影响宁夏C值最主要的因子。

Temporal and Spatial Evolution and Influencing Factors of Wind Erosion Climatic Erosivity in Ningxia

Objective] This paper reveals the temporal and spatial evolution characteristics of wind erosion climate erosivity(C factor)in Ningxia Hui Autonomous Region, expounds the influence and factors of Ningxia climate on wind erosion, and further provides scientific basis for wind erosion evaluation in Ningxia. Methods] Based on the observation data of Ningxia and its surrounding weather stations from 1965 to 2019, according to FAO wind erosion climate erosivity calculation formula, this paper evaluates the temporal and spatial evolution of wind erosion climate erosivity and its influencing factors in Ningxia by using Mann-Kendall trend test, Pettitt catastrophe test, Morlet wavelet analysis and random forest. Results](1)The average C factor of Ningxia was 23.8, on the annual scale and seasonal scale, it showed a sustainable and significant decreasing trend, which was higher in spring and winter and lower in summer and autumn.(2)The average C factor for many years showed a high distribution in the north-central part and a low distribution in the south. A total of 8 stations were significantly reduced, and all of them are sustainable.(3)Except for the summer scale, the C factor of other seasonal scales and annual scales all changed significantly around 2003, and there was a main period of about 30 years.(4)The most important factor affecting C factor was wind speed, followed by precipitation, relative humidity, thermal factors and Pacific Decadal Oscillation. Conclusion] Ningxia belongs to the arid and semi-arid areas with weak climate erosion,and wind speed is the most important factor affecting Ningxia's C factor.