7A.2
Comparisons of surface latent heat fluxes from numerical model simulations with those calculated from buoy observations
Donglian Sun, George Mason University, Fairfax, Viriginia
In this study, we compared and verified surface latent heat fluxes (LHF) from numerical model simulations with those calculated from buoy observations. The LHF values calculated from buoy observations with the Bentamy method, during the maximum hurricane intensity (category 5), are almost half compared to those with the Cione method, while the differences during other times are small. The LHF values from numerical model MM5 simulations depend on the PBL schemes used. The Blackadar and Medium-Range Forecast (MRF) schemes are selected for tests; since they have nearly identical representations of surface fluxes except for the exchange coefficients or the definition of the non-dimensional stability functions are different. The LHF values produced by the Blackadar PBL scheme are almost twice as low as those from the MRF PBL scheme at the time of the maximum intensity, while the differences during other stages are not evident. As a result, the simulated intensity from the Blackadar PBL scheme is weaker than that from the MRF scheme. It is found that MM5 simulated LHF from the Blackadar PBL scheme is close to that calculated from the buoy observations using the exchange coefficient (CE) decreasing with the wind speed (the Bentamy method), while the MRF PBL scheme is close to the Cione method with the CE increasing with the winds.
Session 7A, Ocean-atmosphere interactions and influences on tropical and extratropical storms: Part 2
Tuesday, 13 January 2009, 3:30 PM-5:00 PM, Room 128A
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