石羊河流域风蚀气候侵蚀力时空特征

Spatial and Temporal Characteristics of Wind Erosion Climatic Erosivity in the Shiyang River Basin

摘要:

根据石羊河流域21个气象站1957—2021年的观测资料，计算石羊河流域风蚀气候因子指数C。采用Pearson相关分析、Mann-Kendall（M-K）检测、反距离权重插值及主成分分析等方法，研究石羊河流域C值在年、季节、空间的变化趋势和突变特征，并对相关影响因子进行分析。结果表明：石羊河流域1957—2021年C值为5～146，整个流域的平均值为37。C值呈现出北部荒漠区和沿山区较大，中部绿洲区较小的分布特点。最大C值145.6在流域北部荒漠区民勤红砂岗，最小C值5.5在流域绿洲区古浪土门。流域C值季节变化十分显著，春季最大，夏季次之，春、夏季C值总和占全年的61.2%。流域C值大致在1997年发生突变后极显著下降，突变的发生可能是流域风速在1997年前后发生显著突变所致。累积大风和沙尘暴日数、风速组成的动力因子为影响流域C值的主要气象因子。石羊河流域风蚀气候侵蚀力较强，风速是影响流域C值最主要的气象因子。

Abstract:

Based on observation data from 21 meteorological stations in the Shiyang River Basin from 1957 to 2021, the wind erosion climatic factor index (C factor) was calculated for the Shiyang River Basin. Methods such as Pearson correlation analysis, Mann Kendall (M-K) detection, inverse distance weight interpolation and principal component analysis were employed to analyze the trends and abrupt change characteristics of C factor at annual, seasonal and spatial scales, along with an analysis of relevant influencing factors. The results showed that C factor of the Shiyang River Basin from 1957 to 2021 ranged from 5 to 146, and the average value of the whole basin was 37.Spatially, C factor was higher in the northern desert and along the mountainous areas, and lower in the central oasis areas. The maximum C factor of 145.6 was observed in Hongshagang of Minqin desert area in the northern part of the basin, and the minimum C factor of 5.5 appeared in Tumen of Gulang oasis area of the basin. The basin's C factor showed significant seasonal variations, with the highest in spring, followed by summer, and the lowest in autumn and winter with little difference between them. The sum of C factor in spring and summer accounted for 61.2% of the annual total. On different time scales, the C factor showed a significant declining trend following an abrupt change around 1997, which was most likely caused by the significant abrupt change of wind speed around 1997 in the basin. The primary dynamic factors influencing the basin's C factor were the cumulative number of days with strong wind, cumulative number of sandstorm days and wind speed. The wind erosion climatic erosivity in the Shiyang River Basin was strong, with wind speed identified as the most crucial meteorological factor influencing the basin's C factor.