雅鲁藏布江中游河谷地区的土壤风蚀现状比较严峻。运用土壤风蚀模型可以评估区域土壤风蚀现状，这需要比较准确的近地面风速数据。但由于河谷地区地形起伏大，气象站点少，气象站风速数据的插值结果无法准确描述区域近地面风速的实际分布状况，这会影响土壤风蚀模型的评估结果。地形是影响近地面风速的重要因子之一，要改进风速插值结果，就需要定量认识地形对区域风速的影响。为此，本研究依据雅江中游河谷地区的地形数据，选取了5个地形具有代表性的局部区域，并使用计算流体力学方法模拟了这5个区域的风场；根据模拟结果，进一步探究了各区域近地面风速、风向与地形参数之间的定量关系，并提出了一种考虑河谷宽深比变化的风速校正系数。研究的主要结论如下：
（1）气流经过单个山岭时，不同地形部位的风速、风向分布及变化状况存在差异。在迎风坡前1km处，由于山体阻滞，风速下降，到达山脚时减速约40%；在迎风坡，风顺山坡向上加速，相对高度每增加100m，风加速比增加0.25；在背风坡有回流产生，其平均风速约为初始风速的50%；在背风坡后，靠近山体的区域风速较小，远离山体后风速逐渐增大；在山侧区域，风速增大，风向发生偏转，影响了山后近地面区域的风速。此外，气流经过小起伏地形时，风速的增减与海拔的升降具有一定的同步性。
（2）风在河谷内流动时，风速、风向随河谷宽深比及走向的改变而规律变化。在狭管效应影响下，河谷宽深比越小，风速越大，风速和宽深比之间存在对数形式的函数关系。河谷的走向改变时，风向也发生偏转，而风速变化具有分区特征，转弯前后，风速整体较大，在转弯处，凹岸风速较大，凸岸风速较小。风在地形变化较复杂的河谷中流动时，风速、风向变化状况表现出上述规律的组合与叠加。河谷内次级支沟的存在也影响其内部的风速，这种影响和支沟前侧山脊的走向、坡度及支沟的走向密切相关。
（3）风速和宽深比的定量关系表明，当气象站位于河谷内宽深比较大的区域时，实测数据相比区域风速偏小，反之则偏大。将基于定量关系反演得到的校正系数带入土壤风蚀模型中计算区域土壤风蚀模数，并对比不加入校正系数的计算结果，二者相差10%左右。

The current situation of soil wind erosion in the middle reaches of the the Yarlung Zangbo River is severe. The use of soil wind erosion models can evaluate the current situation of regional soil wind erosion, which requires more accurate near-surface wind speed data. However, due to the large terrain fluctuations in the valley area and the limited number of meteorological stations, the interpolation results of wind speed data from meteorological stations cannot accurately describe the actual distribution of near ground wind speed in the area, which will affect the evaluation results of soil wind erosion models. Terrain is one of the important factors affecting wind speed near the ground. To improve wind speed interpolation results, it is necessary to quantitatively understand the impact of terrain on regional wind speed. Therefore, based on the topographic data of the valley area in the middle reaches of the Yarlung Zangbo River, this study selected five representative local areas of terrain, and used computational fluid dynamics method to simulate the wind fields in these five areas; Based on the simulation results, the quantitative relationship 
between surface wind speed, direction, and terrain parameters in each region was further explored, and a wind speed correction factor considering changes in the width to depth ratio of the river valley was proposed. The main conclusions of the study are as follows: 
(1) When the airflow passes through a single mountain range, there are differences in the distribution and changes of wind speed and direction in different terrain parts. At 1km ahead of the Windward slope, the wind speed drops due to mountain block, and decelerates about 40% when reaching the foot of the mountain; On the Windward slope, the wind accelerates upward along the slope, and the wind acceleration ratio increases by 0.25 for every 100 m increase in relative height; There is backflow on the leeward slope, with an average wind speed of about 50% of the initial wind speed; After the leeward slope, the wind speed is relatively low in the area near the mountain, and gradually increases when away from the mountain; In the mountainous area, the wind speed increases and the wind direction deviates, affecting the wind speed in the near ground area behind the mountain. In addition, when the airflow passes through small undulating terrain, there is a certain degree of synchronization between the increase and decrease of wind speed and the rise and fall of altitude. 
(2) When the wind flows in the valley, the wind speed and direction change regularly with the width to depth ratio and direction of the valley. Under the influence of the narrow tube effect, the smaller the width to depth ratio of the valley, the higher the wind speed, and there is a logarithmic functional relationship between the wind speed and the width to depth ratio. When the direction of the valley changes, the wind direction also deviates, and the wind speed change has a zoning feature. Before and after the turn, the overall wind speed is relatively high. At the turn, the wind speed on the concave bank is relatively high, while the wind speed on the convex bank is relatively low. When wind flows in valleys with complex terrain changes, the changes in wind speed and direction exhibit a combination and superposition of the above laws. The presence of secondary tributaries in the valley also affects the internal wind speed, which is closely related to the direction, slope, and direction of the ridge in front of the tributary. 
(3) The quantitative relationship between wind speed and aspect ratio indicates that when the meteorological station is located in an area with a large aspect ratio in the valley, the measured data shows a smaller wind speed compared to the area, and vice versa. Introduce the wind speed correction factor obtained from quantitative relationship inversion into the soil wind erosion model to calculate the soil wind erosion modulus in the region, and compare the calculation results without adding the correction factor. The difference between the two is about 10%.