雅鲁藏布江中游平坦流沙地表空气动力学特征  

Surface aerodynamic characteristics of flat quicksand in the middle reaches of Yarlung Tsangpo River

作　　者：刘婷 贾晓鹏 陈定梅 益西拉姆 张炎 潘凯佳 张正偲 Liu Ting;Jia Xiaopeng;Chen Dingmei;Yixi Lamu;Zhang Yan;Pan Kaijia;Zhang Zhengcai(Key Laboratory of Desert and Desertification,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China;University of Chinese Academy of Sciences,Beijing 100049,China;Shannan Meteorological Bureau,Shannan 856000,Xizang,China;School of Geography Science and Tourism,ShaanxiNormal University,Xi'an 710119,China)

机构地区：[1]中国科学院西北生态环境资源研究院沙漠与沙漠化重点实验室,甘肃兰州730000 [2]中国科学院大学,北京100049 [3]山南市气象局,西藏山南856000 [4]陕西师范大学地理科学与旅游学院,陕西西安710119

出　　处：《中国沙漠》2023年第5期194-203,共10页Journal of Desert Research

基　　金：中国科学院“西部之光”交叉团队-重点实验室专项;西藏自治区气象局“十三五”重点规划项目“雅江北岸易地扶贫搬迁区沙尘监测与预报预警系统建设”;山南市科学技术局项目(2022BJKJJHXM-007)。

摘　　要：近地层空气动力学过程及特征是影响风沙运动过程及强度的重要因素,受地表粗糙元特征和空气密度等多种因子的影响,是风沙科学研究的重要内容。雅鲁藏布江中游是青藏高原风沙活动最频繁的地区之一,但对其流沙地表空气动力学过程的研究较为薄弱。基于日喀则宽谷和山南宽谷的野外实测风速资料,对流沙地表的风速廓线、空气动力学粗糙度(z_(0))和摩阻风速(u_(*))进行分析,旨在为高海拔风沙运动过程、机理提供理论依据,同时为该地区风沙灾害的防治提供思路。结果表明:(1)空气密度为0.84±0.02 kg·m^(-3)时,流沙地表的风速廓线满足对数函数关系。高海拔地区风速廓线平均截距和斜率大于低海拔地区,说明由海拔引起的空气密度影响近地层气流运动。(2)雅鲁藏布江中游摩阻风速随风速增大而线性增大(R^(2)>0.75),但二者的拟合系数大于前人的研究结果,进一步说明空气密度影响近地层气流运动。(3)u_(*)和z_(0)满足指数模型z_(0)=b_(1)exp(u_(*)/b_(2))+b_(3)。(4)相似均质下垫面条件下,u_(*)和z_(0)与气温、湿度和海拔呈显著正相关,气温的影响最大。The near-ground aerodynamic process and characteristics are important factors affecting the process and intensity of wind-blown sand movement,which are influenced by a variety of factors such as surface roughness characteristics and air density,and are the important contents of the scientific research on wind-blown sand.The middle reaches of Yarlung Tsangpo River are one of the regions with the most frequent wind-blown sand activities in the Qinghai-Tibet Plateau,but the research on the surface aerodynamic process of shifting sand is relatively weak.Based on the field measured wind speed data of Shigatse wide valley and Shannan wide valley,this paper analyzes the wind speed profile,aerodynamic roughness(z_(0))and frictional wind speed(u_(*))of shifting sand surface,aiming to provide theoretical basis for the process and mechanism of high-altitude wind-blown sand movement,and provide ideas for the prevention and control of wind-blown sand disasters in this area.The results show that:(1)When the air density is 0.84±0.02 kg·m^(-3),the wind velocity profile on the surface of quicksand meets the logarithmic function.The mean intercept and slope of wind velocity profile at high altitude are greater than those at low altitude,indicating that air density caused by altitude affects near-ground air flow.(2)The friction wind speed in Yarlung Tsangpo River increases linearly with the increase of wind speed(R^(2)>0.75),but the fitting coefficient between the two is greater than the previous research results,which further indicated that the air density affected the near-formation airflow movement.(3)u_(*)and z_(0)satisfy the exponential model z_(0)=b_(1)exp(u_(*)/b_(2))+b_(3),which is different from previous field measured data and wind tunnel test results(2-parameter exponential model,etc.).(4)Under similar homogeneous underlying surface conditions,u_(*)and z_(0)are significantly positively correlated with air temperature,humidity and altitude,and air temperature has the greatest influence.

关 键 词：雅鲁藏布江 风速廓线 摩阻速度 空气动力学粗糙度 

分 类 号：P931.3[天文地球—自然地理学]