Simulating the effects of the St. Louis urban center on mesoscale convective systems using WRF
| Author(s) | Lawston, Patricia M. | |
| Date Accessioned | 2014-02-24T22:52:26Z | |
| Date Available | 2014-02-24T22:52:26Z | |
| Publication Date | 2012 | |
| Abstract | The potential of an urban center to modify convective storms has long been theorized. An urban center has been shown to deflect small storms around it while enhancing deep, moist convection downwind of the city. We used the Advanced Research Weather Research and Forecasting (WRF-ARW) model to investigate urban influences on mesoscale convective systems (MCS) using case studies. St. Louis was chosen as the urban center of interest for this study, making use of the substantial observational data for the city from the Metropolitan Meteorological Experiment (METROMEX). A series of six events, including three MCS events and three isolated thunderstorm events, in the vicinity of St. Louis, Missouri was modeled. The National Center for Environmental Prediction’s (NCEP) operational Eta 212 grid model output analyses were used for the initial and boundary conditions. In each case study, the ‘urban’ simulation (control) couples an Urban Canopy Model (UCM) to the WRF model for better representation of urban surface fluxes. The ‘no-urban’ simulation (perturbation) uses only the Noah Land Surface model to determine surface fluxes. In addition, all urban land use in the ‘no-urban’ simulation was replaced with an aggregate of crops, woods, and deciduous forest, essentially removing the city of St. Louis. A comparison of the urban and no-urban simulations shows minor but discernible effects on tracking and intensity of isolated thunderstorms and MCS. All events reveal greater total moisture in the low-level column in the urban configuration before the onset of precipitation. In addition, five of the six events showed increases in precipitation over and downwind of the city, including all three MCS events. It is suspected that the city acts as a mechanism for moisture convergence, leading to more precipitation over and downwind of the city, consistent with previous observational and modeling studies. | en_US |
| Advisor | Hanson, Brian | |
| Degree | M.S. | |
| Department | University of Delaware, Department of Geography | |
| URL | http://udspace.udel.edu/handle/19716/12892 | |
| Publisher | University of Delaware | en_US |
| dc.subject.lcsh | Convection (Meteorology) -- Missouri -- Saint Louis -- Computer simulation. | |
| Title | Simulating the effects of the St. Louis urban center on mesoscale convective systems using WRF | en_US |
| Type | Thesis | en_US |