Heights of nocturnal boundary layer (NBL) features are determined using vertical profiles from the Advanced Research Weather Research and Forecasting Model (ARW-WRF), and then compared to data for three moderately windy fair-weather nights during the April-May 1997 Kansas-based Cooperative Atmosphere-Surface Exchange Study (CASES-97) to evaluate the success of four PBL schemes in replicating observations. The schemes are Bougeault-LaCarrere (BouLac), Mellor-Yamada-Janji? (MYJ), quasi-normal scale elimination (QNSE), and Yonsei University (YSU) versions 3.2 and 3.4.1. This study's chosen objectively determinedmodelNBL height h estimate uses a turbulence kinetic energy (TKE) threshold equal to 5TKE'_(max), where TKE' is relative to its background (free atmosphere) value. The YSU-and MYJ-determined h could not be improved upon. Observed heights of the virtual temperature maximum h_(Tvmax) and wind speed maximum h_(Smax), and the heights h_(1wsonde) and h_(2wsonde), between which the radiosonde slows from~5 to ~3ms~(-1) as it rises from turbulent to nonturbulent air, and thus brackets h, were used for comparison to model results. The observations revealed a general pattern: h_(Tvmax) increased through the night, and h_(Tvmax) and h_(Smax) converged with time, and the two mostly lay between h_(1wsonde) and h_(2wsonde) after several hours. Clear failure to adhere to this pattern and large excursions from observations or other PBL schemes revealed excess mixing for BouLac and YSUversion 3.2 (but not version 3.4.1) and excess thermalmixing forQNSE under windy conditions.Observed friction velocity u_* was much smaller than model values, with differences consistent with the observations reflecting local skin drag and the model reflecting regional form drag + skin drag.
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