Accession Number:

ADA522262

Title:

A Coupled Mesoscale-Model Fourier Method for Mountain Waves Over Hawaii

Descriptive Note:

Journal article

Corporate Author:

NAVAL RESEARCH LAB WASHINGTON DC SPACE SCIENCE DIV

Report Date:

2010-01-01

Pagination or Media Count:

31.0

Abstract:

Mesoscale model simulations of representative trade winds impinging upon the Big Island of Hawaii are diagnosed for their mountain wave characteristics by coupling a mesoscale model to a Fourier method. Localized phase-averaged wave momentum fluxes are calculated, which facilitates the study of wave generation from fine-scale topographic features. We find that the wave momentum fluxes are dominated by forcing from subsidiary topographic peaks, with the broader island topography controlling flow splitting and lee vortex generation. Waves also arise at the far northern and southern extremities of the island by acceleration of split flow through conversation of the Bernoulli function. The strength of the local momentum fluxes prove to be sensitive to a small change in the incident flow direction. A really integrated fluxes wave drag align closely with the incident flow direction, and are an order of magnitude smaller than linear predictions and an order of magnitude larger than corresponding dividing streamline predictions. We briefly discuss the relevance of these results to the parameterization of subgrid-scale mountain wave drag in climate and weather models.

Subject Categories:

  • Meteorology

Distribution Statement:

APPROVED FOR PUBLIC RELEASE