Comparison of surface layer turbulence in urban and suburban domains during Joint Urban 2003

Abstract

The Joint Urban 2003 (JUT) project, a cooperative undertaking to study turbulent transport and dispersion in the atmospheric boundary layer conducted in Oklahoma City in the summer of 2003, afforded us the opportunity to increase our understanding of the urban environment. The Army Research Laboratory (ARL) deployed a number of measurement facilities, including a Doppler lidar system, a mobile radiosonde system, a temperature/moisture profiling microwave radiometer, and an array of sonic anemometers mounted on five meteorological towers near and outside the central business district (CBD) in surrounding industrial (urban) and semi-rural (suburban) areas.

This presentation describes the wind and turbulence measurements obtained with the tower systems, emphasizing the similarities and differences in turbulence intensities and momentum and heat fluxes for the two types of domains. Preliminary observations indicated a high degree of vertical transport and mixing in the urban domain, even for relatively stable or neutral conditions. An attempt is made to relate the measured turbulent quantities to expected horizontal and vertical diffusion of aerosol plumes under the variety of wind and stability conditions encountered. Further analyses of these data and the large set of meteorological and diffusion measurements obtained by other agencies and investigators should greatly increase our understanding of the urban boundary layer environment and our ability to predict effects within it.