Observed and Simulated Temporal and Spatial Variations of Gap Outflow Region
NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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This study focuses on understanding the development of gap outflow and the air-sea interaction processes during the 26 February 2004 Tehuano event over the Gulf of Tehuantepec, Mexico. The Navys Coupled Ocean Atmospheric Mesoscale Prediction System COAMPSTM was used to simulate the gap wind event and was compared to satellite, scatterometer, and coincident in situ aircraft and dropsondes measurements collected during the Gulf of Tehuantepec Experiment GOTEX. Comparisons between model results and the observations suggest that COAMPSTM performed the best in simulating the outflow jet within 200 km offshore, although the simulated surface fluxes deviated significantly from the observations. This is the region where the dominant dynamical forcing arises from the coastal topography. Larger discrepancies were found in model result further away from the coast, especially to the south and southeast of the gulf where the air-sea exchange became increasingly important. Detailed inter-comparison between COAMPSTM and the aircraft measurements at 40 m also shows the strong spatial and temporal variations of boundary layer thermodynamics and turbulence, which require improved characterization of the sea surface temperature, upper air conditions, and initial conditions for COAMPSTM. The results also point to the needs for improved surface flux parameterization, particularly in high wind conditions.
- Fluid Mechanics