89th American Meteorological Society Annual Meeting

Monday, 12 January 2009: 11:15 AM
Observed and Simulated Temporal and Spatial Variations of Gap Outflow Region
Room 126A (Phoenix Convention Center)
Qing Wang, Naval Postgraduate School, Monterey, CA; and R. C. Cherrett, S. W. Wang, J. Kalogiros, K. Rados, C. A. Friehe, and D. Khelif
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 Navy's Coupled Ocean Atmospheric Mesoscale Prediction System (COAMPS) was used to simulate the gap wind event and 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 COAMPS 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 with 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 COAMPS and the aircraft measurements at 40 m also shows the strong spatial and temporal variations of boundary layer thermodynamics and turbulence that require improved characterization of the sea surface temperature, upper air conditions, and initial conditions for COAMPS. The results also point to the needs of improved surface flux parameterization, particularly in high wind conditions.

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