P1.2
Adjoint sensitivity study of transcritical flow along the California coast
Clark M. Amerault, NRL, Monterey, CA; and J. Doyle
Summertime northerly flow in the marine atmospheric boundary layer is capped by a strong temperature inversion and channeled along the California coastline by the accompanying terrain. The flow becomes supercritical when the Froude number (dimensionless ratio of the fluid speed to the phase speed of internal gravity waves) is greater than unity. Capes and points modify the flow so that localized regions of both super and subcritical flow exist. Downwind of the coastal feature, air accelerates and the boundary layer compresses, while on the upwind side of a cape, the flow decelerates and the boundary layer deepens. An adjoint mesoscale model is utilized to explore the sensitivity of the coastal flow to synoptic atmospheric parameters and boundary conditions such as the sea surface temperature. The nesting capability of the adjoint model allows for sensitivity calculations of small scale flow characteristics (1 – 5 km) to larger scale features (> 10 km). Furthermore, optimal perturbations are created from the adjoint model fields to investigate the predictability of the flow and to explore the validity of the tangent linear approximation on the mesoscale.
Poster Session 1, IOAS Poster Session I: Data Assimilation and Impact Studies
Monday, 21 January 2008, 2:30 PM-4:00 PM, Exhibit Hall B
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