Street canyon flow patterns in a horizontal plane: Measurements from the Joint Urban 2003 Field Experiment

A large multi-agency urban tracer field experiment called Joint Urban 2003 was conducted in Oklahoma City from the end of June to the end of July. As part of this experiment, an east-west running street canyon was heavily instrumented with sonic anemometers. In this paper, we show flow patterns of the mean velocity field in a horizontal plane above the street surface. Wind measurements were taken at both ends of the street canyon, in the street intersection, and in the central part of the canyon. We have analyzed flow patterns for the Intensive Operating Periods when winds were primarily from the south. We have found significant differences in the flow patterns (e.g., channeling vs. vortex flow, end vortices or not) and will stratify results by inflow wind direction. We hope to be able to predict the occurrence of different flow regimes as a function of ambient wind conditions. This work will help to better understand transport and diffusion in street canyons and may help improve air quality models being developed at this scale.