| The current study used the Martilli-Dupont urbanization scheme within MM5 to investigate Houston urban heat island (UHI) conditions during an August TexAQS 2000 O3-episode. The resulting uMM5 model was used only in the (innermost) fifth domain (1-km grid spacing). Projected changes in vegetative cover for 2010, which showed areas of urban reforestation and rural deforestation, were also simulated by uMM5.; Results showed that input NNRP fields correctly captured the observed large-scale forcing and that the regular MM5 correctly captured the observed sequence of Bay, Gulf, and urban breeze effects on O3-transport. uMM5 better reproduced observed UHI magnitudes and urban impacts on regional flows: roughness-induced deceleration, building-barrier divergence, and UHI-induced convergence. Effects from the use of a higher-resolution domain, uMM5, and/or urban reforestation showed that the first two generally increased daytime UHIs, while reforestation decreased them by an average of 2.8 K and by a maximum (at noon) of 3.3 K. |
