COMPARISON OF MESOSCALE MODEL WITH SODAR WIND AND RADIOMETER TEMPERATURE PROFILER MEASUREMENTS OVER AN URBAN AREA

摘要

In the framework of the project "Development and evaluation of a high resolution atmospheric urban canopy model for energy applications in structured areas" of the Archimedes program funded by the Greek Ministry of Education and Religious Affairs, wind and temperature measurements were conducted in the atmospheric boundary layer (ABL) over the urban area of Kozani, Greece for a time period of about one year using an acoustic sounder (sodar, up to 300 m above ground) and a radiometer profiler (up to 600 m above ground), respectively,. The purpose of this campaign was to evaluate the performance of a mesoscale model (The Air Pollution Model, TAPM, of CSIRO Marine and Atmospheric Research) and more specifically its surface layer and ABL turbulence parameterizations. The TAPM model uses surface similarity and urban parameterizations of various surface parameters (like roughness length and displacement height) to estimate surface turbulent fluxes, and the standard E-? model for the estimation of eddy diffusivity in the ABL. The comparison was limited to selected days that were representative of different conditions of atmospheric wind intensity and atmospheric stability with low acoustic noise, which affects the range of sodar measurements. The comparison showed that the TAPM model forecasts generally performed well with respect to the thermal structure (temperature profiles and ABL height), but overestimated wind speed at the heights of comparison (mostly below 200 m) up to 3-4 ms~(-1). Also, friction velocity and less heat fluxes estimation by the model were generally overestimated by the model when compared (excluding time periods when the forecast didn't predict accurately large scale atmospheric changes) to the corresponding estimates derived by fitting the similarity relations to measured profiles. These differences are probably due to the selected values of the surface parameters or noise problems of the sodar measurements in the quite noisy urban environment.