老哈河下游背风侧谷坡的风速脉动特征  

Wind Velocity Fluctuation Characteristics at Valley Slope of the Lee Side in the Downstream of the Laoha River,China

作　　者：杨林[1] 韩广[1] 胡孟春[2] 王勇[1] 郭宇航[3] 

机构地区：[1]湖南师范大学资源与环境科学学院,湖南长沙410081 [2]环境保护部南京环境科学研究所,江苏南京210042 [3]内蒙古师范大学生命科学与技术学院,内蒙古呼和浩特010022

出　　处：《干旱区研究》2015年第3期579-584,共6页Arid Zone Research

基　　金：国家自然科学基金项目(41271025);湖南省重点学科(地理学)建设项目(2012001)资助

摘　　要：基于老哈河下游春季起沙风地面4.00 m高度范围内实地观测的风速数据,从风速脉动、风速脉动强度两个方面对背风侧谷坡顶和坡脚的风速脉动特征进行分析。结果表明:1坡顶除在0.25 m高度受地表植被和沙粒的跃移运动影响外,风速脉动值和强度都随着距地表高度的增加而逐渐加大,其最大脉动值超过4.00 m·s-1,风速脉动相对值(阵性度)基本稳定;2背风坡脚因谷坡地形突变产生的"二次流",使风速脉动值和相对值都不稳定,脉动强度随着距地表高度的增加而逐渐加大,其最大脉动值超过3.00 m·s-1;3背风坡顶和坡脚各自高度的风速脉动频率具有一致性,但脉动频率不稳定,无明显周期性。坡顶的风速脉动值和强度都大于背风坡脚,但风速脉动相对值小于背风坡脚。Based on wind speed data with field observations from ground 4.00 m height range in sand-windy weather of spring, this paper analyzes the wind velocity fluctuation characteristics of at the slope foot and the slope top at valley slope of the lee side in the downstream of the Laoha River from the following two aspects ： wind velocity fluctuation and wind velocity fluctuation intensity. The results are as follows： （~） Slope top is significantly affected by vegetation and sand saltation movement , the wind velocity fluctuation and intensity increase gradually with the increasing height from surface, the maximum wind velocity fluctuation value exceed 4.00 m ~ s -＇, and the relative wind velocity fluctuation （gustiness） are basically stable;（~） The leeward wind velocity fluctuation value and rela- tive value of the slope foot is not stable due to the presence of ＂secondary air-flow＂ from the terrain mutation of val- ley slope , wind velocity fluctuation intensity increase gradually with increasing height from surface, and the maxi- mum wind velocity fluctuation value exceed 3.00 m ~ s - 1 ; （~） The slope foot and top of the leeward have consistency in wind velocity fluctuation frequency of their height, however, the wind velocity fluctuation frequency are not sta- ble and are not significant periodicity. The wind velocity fluctuation and intensity of slop top are greater than that of the lee slope foot, but relative value are less than the slope foot of the lee slope.

关 键 词：风速廓线 风速脉动 脉动强度 老哈河 内蒙古 

分 类 号：P425.5[天文地球—大气科学及气象学]