基于多源地空耦合数据的青藏高原冻融侵蚀强度评价

[目的]分析和探讨青藏高原冻融侵蚀成因及其空间分布格局,为研究区水土保持研究和生态环境保护提供数据支撑和决策参考。[方法]引入冻融侵蚀动力因子(冻融期降雨侵蚀力和冻融期风场强度)和冻融期降水量(表征冻融期土壤相变水量)构建冻融侵蚀评价模型,进而对青藏高原冻融侵蚀状况开展了定量评价和空间格局分析。[结果]构建的冻融侵蚀评价模型在青藏高原地区具有较高的适用性,总体评价精度为92%;青藏高原冻融侵蚀面积分布广泛,占总面积的63.68%,而非冻融侵蚀区则主要分布于柴达木盆地、雅鲁藏布江流域下游以及横断山区;冻融侵蚀强度随着坡度的上升而增加,15°~24°和≥24°坡度带上冻融侵蚀剧烈,而≤3°坡度带冻融侵蚀强度相对较小;不同植被类型区的冻融侵蚀强度空间分布格局差异显著,其中草甸的冻融侵蚀强度最小。[结论]青藏高原冻融侵蚀状况总体上属于中度侵蚀,其空间分布格局受地形、植被类型和气候影响显著。

Evaluation of Freeze-thaw Erosion in Qinghai-Tibet Plateau Based on Multi-source Data

[Objective] To analyze and explore the causes and the spatial patterns of the freeze-thaw(FT) erosion in Qinghai-Tibet Plateau,and to provide important data support and decision-making references for soil and water conservation research and eco-environment protection in this region.[Methods] The driving force factors of FT erosion(the rainfall erosion and wind field strength during FT period) and the precipitation during FT period(indicating the soil water content) were introduced to establish an evaluation system of FT erosion and then the spatial distribution pattern of FT erosion were analyzed.[Results] The evaluation model of FT erosion had high applicability in Qinghai-Tibet Plateau with the overall evaluation accuracy of 92％.The FT erosion area were widely distributed,covering 63.68％ of the total area;and the non-FT erosion zones were mainly distributed in the lower reaches of the Yarlung Zangbo River Basin,Qaidam Basin and the Hengduan mountains.The intensity of FT erosion increased with the increase of slope.The erosion intensities of 15°～24° and ≥24° slope zone were severe while that of ≤3° slope zone was relatively slight.The spatial distribution patterns of FT erosion intensity among different vegetation types were significantly different.The FT erosion intensities of broad leaved forest and crops were relatively severe while that of meadow was slighter.[Conclusion] The FT erosion of Qinghai-Tibet Plateau belonges to the level of moderate erosion and the spatial patterns are significantly affected by terrain,plant types and climate factors.