Extended Abstract (624K)1.5
Urban growth and aerosol effects on convection over Houston
Gustavo Carrió, Colorado State University, Fort Collins, CO; and W. Y. Cheng, W. R. Cotton, and S. M. Saleeby
In this study we investigate the effects of the Houston metropolitan area on the characteristics and intensity of convection and precipitation, focusing on events triggered by the sea breeze circulation. For this purpose, we implemented the Town Energy Budget (TEB) urban model into the an improved version of RAMS that considers the explicit activation of CCN (and giant CCN), a bimodal representation of cloud droplets, a bin-emulation approach for droplet collection, ice-particle riming, and sedimentation, and direct radiative effects of aerosols. TEB is now coupled to run in parallel as to maximize the full potential of our computing resources. RAMS@CSU is configured to use four two-way interactive nested model grids with 42 vertical levels and horizontal grid spacings of 45.0, 15.0, 3.75, and 0.75 km centered over Houston. Grid 1 (50 X 50 grid points) and grid 2 (71X 61 grid points) are used to simulate the synoptic and mesoscale environments, respectively. While Grids 3 and 4 (102X102 grid points and 202X202 grid points) are used to resolve deep convection as well and the sea breeze circulation . Numerical experiments cover the effects of perturbing both the urban land-use, the aerosol concentrations as well as variations of both.
The Landsat Thematic Mapper ™ National Land Cover Data (NLCD) for the Houston area corresponding to the years 2001 and 2006 were used as benchmarks for the experimental design of the land-use sensitivity experiments, including a run with no city and one of a future scenario. We use aerosol observations during the TexAQS/ GoMACCS field campaign for the initial CCN/GCCN sensitivity experiments. As expected, dramatic impact on the intensity of the convection and precipitation result for the selected case (for August 24 2000). Additional numerical experiments will be performed by only perturbing the land-use input data as well as varying both, aerosol concentration and land-use. Sensitivity experiments with an older NCLD land use data set (1992) will be compared with those using the more recent NCLD land use data to ascertain how changes in land-use affects the meteorology in the Houston area.
Session 1, Severe Storms Impacts on the Urban Environment: Modeling and Observations
Tuesday, 13 January 2009, 3:30 PM-5:00 PM, Room 123
Previous paper Next paper
Recorded presentation