Department of Meteorology, University of Reading, Reading, RG6 6BB, United Kingdom.
Sci Total Environ. 2013 Jan 1;442:527-33. doi: 10.1016/j.scitotenv.2012.10.061. Epub 2012 Nov 29.
Airflow along rivers might provide a key mechanism for ventilation in cities: important for air quality and thermal comfort. Airflow varies in space and time in the vicinity of rivers. Consequently, there is limited utility in point measurements. Ground-based remote sensing offers the opportunity to study 3D airflow in locations which are difficult to observe with conventional approaches. For three months in the winter and spring of 2011, the airflow above the River Thames in central London was observed using a scanning Doppler lidar, a scintillometer and sonic anemometers. First, an inter-comparison showed that lidar-derived mean wind-speed estimates compare almost as well to sonic anemometers (root-mean-square error (rmse) 0.65-0.68 ms(-1)) as comparisons between sonic anemometers (0.35-0.73 ms(-1)). Second, the lidar duo-beam operating strategy provided horizontal transects of wind vectors (comparison with scintillometer rmse 1.12-1.63 ms(-1)) which revealed mean and turbulent airflow across the river and surrounds; in particular, channelled airflow along the river and changes in turbulence quantities consistent with the roughness changes between built and river environments. The results have important consequences for air quality and dispersion around urban rivers, especially given that many cities have high traffic rates on roads located on riverbanks.
这对空气质量和热舒适度很重要。气流在河流附近的空间和时间上发生变化。因此，点测量的应用有限。地面遥感为研究传统方法难以观察到的位置的 3D 气流提供了机会。2011 年冬季和春季的三个月里，使用扫描多普勒激光雷达、闪烁仪和声速仪观测了伦敦市中心泰晤士河上方的气流。首先，相互比较表明，激光雷达得出的平均风速估计值与声速仪的比较几乎一样好（均方根误差（rmse）为 0.65-0.68 ms(-1))），与声速仪的比较（0.35-0.73 ms(-1))。其次，激光雷达双光束操作策略提供了风矢量的水平横切（与闪烁仪的 rmse 为 1.12-1.63 ms(-1))），揭示了河流和周围的平均和湍流气流；特别是，沿着河流的通道气流和与建筑物和河流环境之间的粗糙度变化一致的湍流量的变化。这些结果对城市河流周围的空气质量和扩散有重要影响，特别是考虑到许多城市的河岸上都有高交通流量的道路。
