Subjects: Geosciences >> Geography submitted time 2023-04-07 Cooperative journals: 《干旱区地理》
Abstract： Aerodynamic roughness is defined as the height at which the wind speed becomes zero under neutral and stable conditions. It is an important parameter for measuring the momentum and energy exchange between the underlying surface and atmosphere, and it is critical for investigating various surface processes and climate change. However, it has always been difficult to estimate aerodynamic roughness accurately at the regional scale, and there is no unified estimation model presently. Therefore, the parameterization of aerodynamic roughness is a topic worthy of further study. As a long-range monitoring method, remote sensing technology has the advantages of macroscopic and rapid acquisition of ground feature information, and its ability to achieve dynamic monitoring at the regional scale or a larger scale in estimating the aerodynamic roughness of vegetation-covered surfaces. Therefore, using remote sensing technology to estimate aerodynamic roughness has become a hot issue at home and abroad in recent years. In this study, the progress of research on aerodynamic roughness at home and abroad in recent years is systematically described. The estimation methods are divided into two categories: one is based on measured data, and the other is the remote sensing method, which is rapidly advancing. This study primarily introduces the method of estimating the aerodynamic roughness of the underlying surface of vegetation by remote sensing technology. Methods based on measured data include the canopy height fixed ratio method, field experiment method, and wind tunnel method; remote sensing methods include vegetation index, LIDAR, and multisource remote sensing synergistic methods. In addition, the advantages and disadvantages of the different methods are summarized at the end of each section. Finally, this study analyses the influence of meteorological factors and morphological characteristics of surface roughness elements on aerodynamic roughness and discusses the development trends and problems of remote sensing techniques in estimating aerodynamic roughness, aiming to provide ideas for subsequent research on remote sensing monitoring of aerodynamic roughness.
Subjects: Geosciences >> Atmospheric Sciences submitted time 2018-10-23 Cooperative journals: 《干旱区地理》
Abstract： 利用北方风蚀区155个气象站点1971—2015年平均风速数据，采用气候趋势分析、空间插值和小波分析等方法分析北方风蚀区平均风速的时空变化趋势。结果表明：近45a 来，北方风蚀区年平均风速为2.70 m•s-1，呈明显减小趋势，其递减速率为0.017 m•(s•a) -1 (α=0.001)，1980s风速减小最快，1990s减小最缓慢,2010s风速出现增大趋势；我国北方风蚀区四季的平均风速均呈现下降趋势，下降速度春季>夏季>秋季>冬季（α=0.001），不同年代不同季节风速变化存在较大差异，2010s除春季外其他季节风速均呈现增大趋势；空间分布上显示，风速变化幅度空间分布差异明显，北方风蚀区内的新疆西北部和东南部、青海、内蒙古中部和东北部、黑龙江以及吉林为风速降低较快的区域，甘肃东南部、宁夏、陕西和山西北部以及新疆的东北部和西部等地区是风速降低不明显的区域。春季和夏季风速降低较快的区域面积扩大，冬季和秋季风速降低较缓的区域扩大；平均风速存在多时间尺度的周期性结构特征，28 a时间尺度左右为风速变化的主周期，平均变化周期为18 a。
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