石羊河流域下游青土湖近地层风尘分布特征  

Dust distribution characteristics of Qingtu Lake surface layer at downstream Shiyang River

作　　者：郭树江[1,2] 杨自辉[1,2,3] 王多泽[1,2] 王强强[1,2] 张剑挥[1,2] 张大彪[1,2] 詹科杰 李易珺[1,2] 

机构地区：[1]甘肃省治沙研究所,甘肃兰州730070 [2]甘肃民勤荒漠草地生态系统国家野外科学观测研究站,甘肃民勤733300 [3]甘肃省荒漠化与风沙灾害防治国家重点实验室(培育基地),甘肃武威733000

出　　处：《干旱区地理》2016年第6期1255-1262,共8页Arid Land Geography

基　　金：国家林业公益性行业科研专项(201404306);甘肃省青年基金计划项目(145RJYA270)

摘　　要：青土湖属于极端干旱区典型的干涸盐湖,盐尘中含有密度很高、粒径极细的盐碱粉尘,严重污染空气,危害地表植被,威胁干旱区绿洲生态安全。利用建立在青土湖的近地层0~50 m沙尘观测系统近2 a监测的数据,对近地层0~50 m盐尘的分布规律及风速的变化特征进行研究。结果表明：（1）风速在0~50 m垂直梯度的分布符合经典的风速随高度的增加而增大的基本特征,廓线方程遵循幂函数关系;年内月平均风速最大为5月,最小为11月,且表现出明显的季节变化特征,春、夏季平均风速大于秋、冬季;近地层18~2 m内风切变指数较大,且春、夏季风切变指数相对较小;34~28 m、50~34 m内风切变指数变化较小,且四季变化不明显。（2）盐碱沙尘水平通量的空间分布随高度的增加而增加,在垂直高度上遵循幂函数变化规律;受下垫面梭梭林的影响,在6 m高度处有一个较为明显的增加。（3）沙尘水平通量与风速之间呈现出幂函数关系,且呈明显的正相关关系。Qingtu Lake is a typical dry salt lake located at the downstream Shiyang River,Minqin County,Gansu Province,China in extreme arid areas. Under the action of wind,salt dust pollutes air,harms the surface vegetation,threatens ecological security and people＇s life seriously. Based on the soil dust data monitored by dust observation system in Qingtu Lake 0-50 meters surface layer,this paper analyzed the saline dust movement rule,the change characteristics of wind speed,and their relationship in each vertical gradient. In order to reveal the distribution characteristics of salt dust flux level,this paper also provided a reference for effective governance and accurate prediction of sand and dust weather in the area. The observation system consists of a 50 m high climb type observation tower and installations including the wind flux tracking filter dust level instrument,wind speed and direction,temperature,humidity,air pressure sensor and data collection and transmission system. The characteristics of dust change were monitored dynamically at 10 vertical gradients（1 m,2 m,6 m,10 m,14 m,18 m,26 m,34 m,42 m and 50 m）. The results show as follows：（1）The distribution of wind speed in the 0-50 m vertical gradient followed the classic characteristics that wind speed increased with the increase of height,and the profile equation followed a power function relationship. The average wind speed was the maximum in May,the minimum in November,and showed significant seasonal variation characteristics;average wind speed in spring and summer was greater than that in autumn and winter. Wind shear index was larger in 18-2 m surface layer,and it was relatively small in the spring and summer;wind shear index change was small in 34-28 m and 50-34 m,the changes among the four seasons were not obvious.（2）The spatial distribution of saline dust flux level increased with the increase of height,and follow the change rule of power function in the vertical height;affected by Chenopodiaceae forest underlying surface,the saline dust

关 键 词：石羊河下游 近地层 风尘变化 

分 类 号：X513[环境科学与工程—环境工程]