基于不同模型的黄河中游降雨侵蚀力时空变化分析

[目的] 基于不同模型探究黄河中游地区降雨侵蚀力的时空演变特征，为该地区水土流失危害评估、水土保持措施规划提供参考依据。[方法] 采用黄河中游1981—2020年日降雨量数据集，基于两种降雨侵蚀力模型探究了降雨和降雨侵蚀性的时空变化特征。 [结果] 黄河中游年均降雨量为349.90～699.90 mm，空间上自东南向西北呈波浪形递减趋势，时间上呈多峰状不显著的波动上升趋势特征，存在2 a主周期变化特征。黄河中游两种模型的降雨侵蚀力年际变化趋势特征和周期性相似，但降雨量越大的地区，两模型估算的降雨侵蚀力结果相差越大。谢云模型估算的降雨侵蚀力结果与降雨量相对更拟合。黄河中游年均降雨侵蚀力为767.00～3 003.40 MJ·mm/(hm²·h)，具有高度月度集中性，集中于7—8月，呈单峰型。 [结论] 黄河中游年均降雨侵蚀力具有显著的垂直空间差异，且在地形和地貌影响下空间差异会发生变化，高海拔地区的变化系数通常高于低海拔地区。在东南部秦岭山区和关中平原等地区，随海拔升高，降雨侵蚀力迅速减少，在西北部黄土高原区，随海拔升高而逐渐增加。因此在黄河中游降雨侵蚀性增加的地区，应采取适当措施，减少土壤侵蚀的潜在风险，确保区域生态安全的可持续发展。

Temporal and Spatial Variation of Rainfall Erosivity in Middle Reaches of Yellow River Based on Different Models

[Objective] Based on different models, the spatiotemporal evolution characteristics of rainfall erosivity in the middle reaches of the Yellow River were explored, in order to providing a reference basis for the assessment of soil erosion hazards and planning of soil and water conservation measures in this area. [Methods] Daily rainfall data from 1981 to 2020 for the middle reaches of the Yellow River was used to explore the temporal and spatial variation characteristics of rainfall and rainfall erosivity based on two rainfall erosivity models. [Results] Average annual rainfall in the middle reaches of the Yellow River was between 349.90 mm and 699.90 mm. Spatial variation followed a fluctuating decreasing trend from southeast to northwest. Temporal variation exhibited a multi-peak insignificant upward fluctuation that had a 2-year main cycle change feature. There were some similarities between the two models of rainfall erosivity from the interannual trend characteristics and periodicity in the middle reaches of the Yellow River. However, areas with greater rainfall exhibited greater differences in rainfall erosivity estimated by the two models. The average annual rainfall erosivity in the middle reaches of the Yellow River was 767.00~3 003.40 MJ·mm/(hm²·h), exhibiting a high monthly concentration (concentrated in July-August) and showing a single peak shape. [Conclusion] There were significant vertical spatial differences from annual average rainfall erosivity in the middle reaches of the Yellow River, and there were spatial differences resulting from the influence of topography and landforms. The coefficient of variation in high-altitude areas was generally greater than in low-altitude areas. In the Qinling Mountains and the Guanzhong Plain in the southeast, the erosivity of rainfall decreased rapidly with increasing altitude. In in the northwest of the Loess Plateau region, the erosivity of rainfall increased gradually with increasing altitude. Therefore, in areas where erosivity of rainfall increases in the middle reaches of the Yellow River, appropriate measures should be taken to reduce the potential risk of soil erosion and to ensure the sustainable development of regional ecological security.