Effects of Shear and Wind Profile Curvature on Gravity Wave Drag
Abstract
Numerical simulations with mesoscale models indicate that surface gravity wave drag is sensitive to the shape of the wind profile. This is a well known feature of flow past large mountains, where resonant flows may be established for some background profiles of wind and stability. In the limit of linear flow, the effect of linear shear has been studied in recent years and found to lead to a reduction of drag. This paper develops an analytical model that incorporates more general wind profiles, which are characterized by both wind shear and curvature, using a linearized set of equations that treats nonlinearities associated with the vertical variation of wind speed using a WKB approximation. The results of that model indicate that curvature effects may be substantial, and lead to significant increases in the surface drag. Results of that analytical model compare very well with sets of numerical simulations with a mesoscale model. It is suggested that the simple formula that come out of the analytical model may be incorporated into parameterization schemes.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2003
- Bibcode:
- 2003AGUFM.A42B0755T
- Keywords:
-
- 3329 Mesoscale meteorology;
- 3337 Numerical modeling and data assimilation;
- 3367 Theoretical modeling;
- 3384 Waves and tides