Urban turbulence spectra from field observations

Abstract

A simple analytical form is used to model turbulent velocity and temperature spectra obtained from measurements with sonic anemometers mounted on a tall tower in an urban boundary layer. The form of the function used to model the spectra has two free parameters determined from the measurements with a non-linear curve fitting method. Conducted in Oklahoma City in the summer of 2003, the Joint Urban 2003 (JU2003) field experiments were a cooperative undertaking to study transport and dispersion in the turbulent atmospheric boundary layer. Sonic anemometer data taken using Lawrence Livermore National Laboratory's 83-m pseudo tower from JU2003 are analyzed. We present the results of characteristics of the urban turbulence spectra. In particular, we investigate the vertical variations detected in the urban spectra. We also discuss differences in the spectra observed over urban and non-urban areas.