Impact of environmental flows on the daytime urban boundary layer structures over the Baltimore metropolitan region

The three-dimensional structures of the urban daytime boundary layer (UDBL) over Baltimore are examined using a coupled Weather Research and Forecast-Urban Canopy model. Results show the upward growth of the urban heat island (UHI) effects as the surface-based 'hot plumes' with pronounced rising motions and thermal gradients. The UDBL tends to exhibit different vertical structures and intensities, depending on the magnitude and direction of environmental flows with respect to urban morphometric distributions and its interaction with the circulations induced by differential land covers. They are determined by both the local UHI effects and the nonlocal advective processes. Copyright (C) 2010 Royal Meteorological Society