Quantitative and Qualitative Evaluation of a Three-Dimensional Mesoscale Numerical Model Simulation of a Sea Breeze in Complex Terrain

Abstract

This study presents an evaluation of the performance of the Colorado State University (CSU) three-dimensional numerical mesoscale model. The evaluation consists of quantitative and qualitative comparisons of the model output with observed data. The observations were undertaken in the lower Fraser Valley of British Columbia, Canada on 23 August 1985 utilizing up to 23 fixed stations for anemometry, three acoustic sounders, one tethersonde and one set of instruments for determining the surface energy budget terms. The modeling covers a 24-hour period during which a wed-developed sea breeze was observed. While the results of the model evaluation apply to the single case presented, they have implications for a wide range of cases. The statistical methods of Willmott are applied to hourly averaged variables to assess the model's performance. The evaluation shows that the model is capable of providing very realistic wind and temperature fields within the broad coastal valley which makes up the bulk of the domain. The modeled mixed layer depth, surface energy budget terms and wind profiles are in good agreement with observed data.