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Hurricanes Innovative Grid-Enable Multiple-scale Hurricane modeling system. Konstantinos Menelaou International Hurricane Research Center Department of Earth Sciences Florida International University. Physical structure of Hurricanes.
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Hurricanes Innovative Grid-Enable Multiple-scale Hurricane modeling system Konstantinos Menelaou International Hurricane Research Center Department of Earth Sciences Florida International University
Physical structure of Hurricanes • Hurricanes are intense whirling storms that develop over the tropical oceans in regions of very warm surface water. • Hurricanes are distinguished by their driving force—heating from an underlying warm ocean—and by their intensity . • The kinetic energy of hurricanes is maintained in the presence of boundary layer by the conversion of latent heat energy acquired from the underlying ocean. • This energy conversion is carried out by circulation associated with the hurricane. • This circulation inflow into a region of enhanced conversion surrounding the storm center that is referred as the eyewall.
Why hurricane boundary layer turbulence is important? Hurricane boundary layer turbulent processes have a direct socio-economic impact on coastal communities and resources.
It is through the boundary layer that a hurricane gets energy. Momentum Friction Water Vapor Turbulence Heat Warm ocean surface Turbulent transport Up-scale impact on hurricane by providing energy to maintain hurricane vortex. Down-scale impact on coastal communities during landfall.
Scale (km) 1800 180 18 1.8 0.18 0.018 Van de Hoven 100 m Operational model Grid-size • Can current boundary layer turbulence parameterization schemes realistically represent the turbulent transport in high hurricane wind conditions? • How can we predict the HBL organized structures and the associated damaging winds for hurricane wind damage Mitigation? clouds turbulence Parameterization Large eddy simulation
Classic Large eddy simulation (LES) • Simulation domain cannot be very large, typically about tens of kilometers. • Initialized with idealized vertical profiles and forced with uniform surface conditions and horizontal homogeneous large-scale atmospheric forcings. • Hurricane vortex is a moving target. • Swirling hurricane wind changes the speed and direction continuously. Classic LES cannot be used to study HBL
WRF large-eddy simulation (WRF-LES) Hurricane Ivan Portable Wind Tower (PWT)
The problem can be solved by increasing model resolution so that small scale processes, such as large turbulent eddies and clouds, are explicitly resolved. • LES can be executed in a weather forecasting mode by nesting an LES domain in mesoscale models (Zhu 2007). • Such multi-scale simulations open the door to simulate background flow, hurricane vortex, and down to turbulent eddies in a unified system. PROPOSAL : Developmen of a multi-scale modeling system from Weather Forecast & Research (WRF) model including an online LES domain to explicitly simulate large turbulent eddies in a weather forecasting mode.