| 英文摘要: | PREEVENTS Track 2: Collaborative Research
More resilient coastal cities and better hurricane forecasts through multi-scale modeling of extreme winds in the urban canopy
Award 1663978
When a hurricane arrives at the coast, what happens to wind near the ground depends on what is covering the ground. Whether that covering is grass, trees, pavement, a scattering of small houses, or a densely packed cluster of skyscrapers will affect the wind?s speed, direction, and gustiness. Such effects can vary from one part of a city to another, even from one side of a building to another. Experts do not understand such variations as well as they would like. Computer models used to forecast weather have become more accurate and detailed over the decades but provide little information about how wind speeds and wind gusts vary across city and suburban landscapes. The goal of this project is to use state-of-the-art computer models to learn more about and to improve our ability to predict how buildings disrupt and modify the wind beneath landfalling hurricanes, from just above the ground to near the tops of buildings. Results will foster better ways to design and locate buildings and other infrastructure near coasts, better ways to forecast hurricane-force winds, better ways to protect lives and property in the face of impending landfall, and better ways to respond immediately afterward. The project will include 1 graduate student to help provide for the next generation of researchers in this area.
Through computer simulations during the project?s first phase, a range of standard building types in different layouts will be subjected to strikes from archetypal hurricanes. The simulations will reveal the most important, fundamental physical processes at play on scales that are usually invisible to typical weather forecast models yet are critical to the variation of wind in urban and suburban landscapes. Armed with the knowledge gained in that first phase, during phase II researchers will then improve the components of the industry-standard Weather Research and Forecasting (WRF) Model that are most directly responsible for predicting wind in developed areas. Those components were designed to work best for the lower wind speeds typical of most weather, not for hurricane-force winds. The improved WRF Model from phase II of the project will then be used in phase III to simulate the actual landfall of at least one historical hurricane. Researchers will retrieve records of the hurricane?s weather observations and wind damage to validate the improved model, evaluating how its representation of hurricane-force winds in urban and suburban areas has been enhanced. In phase IV, researchers will review more past hurricanes that made landfall in the U.S. and Mexico to select a subset of storms for additional simulations. Conditions will be perturbed to change the characteristics of those actual storms, generating a collection, often called an ensemble, of synthetic hurricanes that spans a realistically wide range of types. Finally, in phase V of the project, results from phase IV will be combined with socioeconomic information and mathematical equations for wind damage to create maps of how the vulnerability to high winds in hurricanes varies within the cities selected in phase IV. |