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Title: Evaluation of Urban Canopy Models against Near-Surface Measurements in Houston during a Strong Frontal Passage
Urban canopy models (UCMs) in mesoscale numerical weather prediction models need evaluation to understand biases in urban environments under a range of conditions. The authors evaluate a new drag formula in the Weather Research and Forecasting (WRF) model’s multilayer UCM, the Building Effect Parameterization combined with the Building Energy Model (BEP+BEM), against both in-situ measurements in the urban environment as well as simulations with a simple bulk scheme and BEP+BEM using the old drag formula. The new drag formula varies with building packing density, while the old drag formula is constant. The case study is a strong cold frontal passage that occurred in Houston during the winter of 2017, causing high winds. It is found that both BEP+BEM simulations have lower peak wind speeds, consistent with near-surface measurements, while the bulk simulation has winds that are too strong. The constant-drag BEP+BEM simulation has a near-zero wind speed bias, while the new-drag simulation has a negative bias. Although the focus is on the impact of drag on the urban wind speeds, both BEP+BEM simulations have larger negative biases in the near-surface temperature than the bulk-scheme simulation. Reasons for the different performances are discussed.  more » « less
Award ID(s):
1663978
PAR ID:
10381387
Author(s) / Creator(s):
;
Date Published:
Journal Name:
Atmosphere
Volume:
13
Issue:
10
ISSN:
2073-4433
Page Range / eLocation ID:
1548
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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