The Influences of Urban Building Complexes on the Ambient Winds over the Washington-Baltimore Corridor
MENGLIN S. JIN, Y. X. SHOU, CHUNQING DONG, DALIN ZHANG
ABSTRACT
This paper examines the collective impacts of urban building complexes on the boundary-layer winds using both observations and a mesoscale model. Near surface winds measured for two large cities (i.e., Washington, DC, and Baltimore, MD) and a small city nearby (Reston, VA) on the roofs of the federal buildings show evident blocking effects of the urban building complexes on the downstream winds during the daytime of 10 July 2007. A modeling study of the case using the Weather Research and Forecasting (WRF)/Noah/single-layer urban canopy model (SLUCM) as well as Multi-Layer Urban Canopy Model (MUC), in which the observed building height and density information is implemented into both urban schemes to advance the traditional calculation of momentum, heat, and turbulent kinetic energy, reproduces the observed surface winds, in particular, surface wakes. Results show that under stable conditions the building complexes can collectively form a mesoscale wake on the downwind side of each city, about 2-5 km away from the edge of the building complexes. The wake flow may extend up to 1.5 km altitude, depending on the height of the building complexes and the time of the day.