Air Flow Over Large Scale Topography
Abstract
This project studied the two aspects of topographic influence on transient atmospheric motions: 1) Lee Cyclogenesis. It is observed that cyclones frequently form on the lee side of mid-latitude mountain ranges. This problem is investigated with a long mountain range which is perpendicular to a vertically sheared basic current. The prediction equations are solved with both analytic and numerical methods. It is found that lee cyclogenesis can be partially explained by a superposition effect involving a counterclockwise rotating cyclone and a clockwise rotation circulation forced by the mountain range. 2) Effects of topography on fronts. It is often observed that fronts are strongly affected by topography. A two-dimensional numerical model is used for this study. The model predicts the formation of fronts through the effects of a confluent horizontal wind field. When a front is placed on the upwind side of a mountain range, it weakens relative to the no-mountain solution as it moves up the slope, and it strengthens as it moves down the lee slope. The collapse of a front to very small scales is studied with a non-hydrrostatic numerical model. It is found that this process excites gravity waves.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1989
- Accession Number
- ADA211779
Entities
People
- Mary A. Rennick
- Roger T. Williams
Organizations
- Naval Postgraduate School