Sunday, 20 January 2008
Simulation of hurricane-ocean interaction for hurricane Katrina: Coupling the Weather Research and Forecasting (WRF) model with a 1-D ocean model
Exhibit Hall B (Ernest N. Morial Convention Center)
Given the documented increase in shoreline habitation in hurricane zones and recent hurricane disasters such as Katrina (2005), every effort should be made to improve the accuracy of hurricane simulations. In this research project, a simulation of Katrina was run using the Weather Research and Forecasting (WRF) atmospheric, numerical model coupled with the 1-Dimensional (1-D) PWP (Price-Weller-Pinkel) isolated-column ocean model. The goal of this study was to determine the sufficiency of coupling with a 1-D ocean model in terms of the accuracy of the ocean response to the hurricane and the ocean feedback (the hurricane response). There are two parts of the ocean response, local mixing and upwelling. Both components bring deeper, colder water up to the surface, decreasing the temperature of the warmer, surface mixed layer. This cooling decreases the amount of energy available to the storm. The PWP ocean model is only able to simulate the local mixing element of the ocean response. However, a full 3-D ocean model is needed to account for the upwelling factor as well. Results show that coupling WRF with the PWP ocean model does not produce a significant hurricane response. This result can be attributed to how the PWP has to be initialized due to its simplicity, and to the model's inability to capture the upwelling component of the ocean response. We anticipate that using a 3-D ocean model will produce a simulation that more closely follows actual events in terms of the physics of the hurricane-ocean interaction due to the 3-D model's ability to use a more complete initialization procedure, and its ability to capture both aspects of the ocean response.
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