中国风蚀景观面积变化与 地表风场强度的关系

利用遥感调查的1995－2000年中国土地利用成果进行中国风蚀景观变化过程的分类，对不同风蚀景观发展过程进行了地理分区。探讨风蚀景观变化的方向和速度，特别是土地发生风蚀沙漠化的趋势。在中国近400个气象站点1999年每日4次观测数据的基础上，进行风向频率、风场强度及风能参数的计算，分析风速频率Weibull分布的形状参数k和幅度参数c。利用GIS方法生成覆盖中国的1km网格，对风场强度等数据进行空间化处理，生成中国地表风速空间分布数据。在此基础上，分析1999年风速变化状况并探讨风场的变化过程。利用RWEQ风蚀预报模型中的计算方法生成了的风场强度指数。结合风场强度数据，进行风蚀区内风蚀景观变化类型分布数据的对比，指出强风场的存在促使中国西北广大干旱区的草地和耕地遭到破坏，并探讨了风能对土壤风力侵蚀和风蚀景观的驱动过程。同时，在分析风能与风蚀景观空间分布关系的基础上探讨了降低土壤风蚀的措施。最后指出了建立风速和风向驱动下的不同景观的土壤颗粒侵蚀和堆积量模型的重要性。

Analysis of Wind Erosion Caused Landscape Change and Its Relation with Spatial Distribution of Wind Energy

Based on the results of the remote sensing investigations of the land-use and land-cover of 1995 and 2000, the national distribution of sandy desertified land and its interaction with other landscapes are classified, and five zonal types are distinguished. In arid and semi-arid areas of China, the intensity of wind field is one of the key factors that control the development of landscape especially in desert and its adjacent area. To better understand the spatial distribution of wind erosion landscapes as well as their dynamic changes, essential work is needed to expose the spatial distribution of wind field and its changes. In the paper, the data of nationally distributed 400 meteorological stations of 1999 are processed. With the GIS method, the data are spatially interpolated, and the national database of wind field concerned with wind erosion is established. Wind speed and its duration are one of the most important factors that control wind erosion of soil. When the friction speed is satisfied, wind erosion occurs. Different indexes are set up to describe the intensity of wind field, such as the number of days that their daily average wind speed exceeds the value of threshold speed and the number of records that their speed surpass the threshold speed. The method suggested by the wind erosion prediction models of RWEQ is also adopted to express the intensity of wind. The results are compared, and the distribution of wind field in China is discussed. The relation of the distribution of landscape and wind field is then discussed indicating the strong wind field in Northwest China as a most important factor that causes serious landscape change especially to the diminishing of the grassland and contrarily the expansion of the sandy desertified land.