典型天气背景下沙漠绿洲过渡带近地表风动力空间变化特征  

Spatial variation of wind dynamical characteristics in the desert-oasis transitional zone under typical weather conditions

作　　者：张克存[1] 安志山[1] 蔡迪文 郭紫晨[1] 王军战[1] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所敦煌戈壁荒漠生态与环境研究站,沙漠与沙漠化重点实验室,甘肃兰州730000

出　　处：《干旱区地理》2016年第5期1004-1010,共7页Arid Land Geography

基　　金：国家自然科学基金项目(41371027;41401408);中科院青年创新促进会项目(2014382)共同资助

摘　　要：以地处鸣沙山边缘的敦煌绿洲为例,沿沙漠至绿洲方向设置监测断面,利用沙漠、绿洲和过渡带三点定位气象数据,结合移动式多路梯度风况资料,选取晴天、浮尘、扬沙和沙尘暴4个典型天气环境,分析探讨了不同天气背景下,沙漠绿洲过渡带局地风况、近地表风速廓线、摩阻速度和输沙势等风动力环境的空间变化特征。由于受沙漠绿洲过渡带的影响,沿沙漠至绿洲方向,平均风速、起沙风频次和输沙势均逐渐减小,主导风向也发生偏转。其中沙尘天气环境下,沙漠、过渡带和绿洲起沙风频次分别为96,48和7,过渡带和绿洲边缘平均风速较沙漠区减小约22.2%和50.2%。研究结果有助于解决绿洲风沙危害,确保沙漠绿洲的生态安全,更能为干旱区绿洲风沙防护体系建设提供理论依据。Controlled by the landscape pattern of oasis and desert,the processes of wind-blown sand in the oasis-desert transitional zone have direct impact on the stability of oasis. In this paper,a typical oasis-desert transitional zone in Dunhuang Oasis at the east of Kumtagh Desert between Xinjiang and Gansu Province,China was selected the our studying site. With the methods of setting section from desert to oasis,fixed point observation in the field and mathematical statistics,the sand-laden wind,drift potential and drag velocity were calculated based on the meteorological data of the sites in the desert,oasis and desert-oasis transitional zone. This paper probes into the local wind regimes,wind speed profile,aeolian environments and drift potentials along the desert-oasis transitional zone under typical weather conditions. Results show that the frequency of sand-laden wind decreases obviously from desert to oasis,especially in the condition of sandstorm weather. The frequency of sand-laden wind is 96 in the desert,58 in the desert-oasis transitional zone and 7 in the oasis,respectively. Due to the impacts of the desert-oasis transitional zone,the dominant direction of wind also deviates from desert to oasis. Wind speed decreases from 8.59 m·s^-1in the site of desert to 4.28 m·s^-1in the site of oasis in sandstorm weather,which indicates an obvious defensive effect of oasis. In addition,drag velocity is 0.51 m·s^-1in the desert,0.27 m·s^-1in the desert-oasis transitional zone and 0.14 m·s^-1in the oasis. Wind speeds on different heights have good correlation under the same underlying surface. The relationship of wind speeds on different heights decreases from desert to oasis. In the field observation periods,the site of desert has 196.81 VU of drift potential,which indicates high wind energy and strong aeolian sand activities. While in the sites of desert-oasis transitional zone and oasis,drift potential is 68.45 VU and 9.35 VU,both lower than that in desert. The result of this paper is beneficial to solve the san

关 键 词：天气背景 沙漠绿洲过渡带 起沙风 摩阻速度 输沙势 

分 类 号：P425[天文地球—大气科学及气象学]