Abstract
The classification of horizontal flow field above an urban area were conducted using doppler velocity distribution observed by Doppler lidar. The Doppler lidar measurement used for the current analysis, was conducted in Tokyo, from 20 August to 24 November, 2011. The measured velocity fields were classified visually into 4 groups; streak, fish net, front, and the others. And the each groupe has the different range in magnitude of Velocity Azmith Display (VAD) components; horizontal mean velocity, divergence and deformation. The atmospheric stability also affected to the existence of fish net pattern and to the spatial scale of streaky pattern. The effects of surface roughness and topography on the flow fields, such as the wakes of tall buildings triggering streaky patters and deformation of micro-front due to the small hills, were clearly illustrated.
