87th AMS Annual Meeting

Tuesday, 16 January 2007: 11:00 AM
The impact of current and future urban land use on coastal convective precipitation
214A (Henry B. Gonzalez Convention Center)
J. Marshall Shepherd, Univ. of Georgia, Athens, GA; and M. Manyin and D. Messen
There is increasing evidence that urbanization can have a significant feedback on the weather-climate system. The approach of this study is to determine what impact current and future urban land use in the coastal city of Houston has on convective processes and precipitation. A case study framework based on a typical sea-breeze convective day in Houston, Texas is applied. Mesoscale model simulations of current urban land use and “no urban” land use suggest that urban rainfall northwest of the city was likely induced by urban forcing related to the urban heat island, sensible heat flux, and moisture convergence. This response is given the terminology the “urban rainfall effect or URE.” An urban growth model (UrbanSim) is used to project the urban growth of Houston, Texas from 1992 to 2025. Then, a mesoscale atmospheric-land surface model with the 2025 urban land use scenario is run. Our results indicate that convective evolution and precipitation totals will be significantly different in the coastal-urban region around Houston under projected growth scenarios for urban land, assuming a similar meteorological regime. Changing only the urban land use, the 2025 simulations produced a factor of two more rainfall than the current (e.g. 2001) case and a more sustained and widespread precipitation event.. These findings have implications for ongoing discussions on what factors will contribute to changes in weather, climate and Earth's water cycle processes

Supplementary URL: