A two-dimensional numerical study of horizontal roll vortices in the neutral atmospheric boundary layer

✍ Scribed by P. J. Mason; R. I. Sykes

• Publisher: John Wiley and Sons
• Year: 1980
• Tongue: English
• Weight: 1020 KB
• Volume: 106
• Category: Article
• ISSN: 0035-9009
• DOI: 10.1002/qj.49710644808

✦ Synopsis

Abstract

The dynamics of large‐scale, horizontal roll vortices in the neutral planetary boundary layer are investigated by means of a two‐dimensional numerical model. The rolls are assumed to be two‐dimensional and are calculated explicitly, while small‐scale turbulence is parametrized by a mixing‐length hypothesis. Although buoyancy effects are never negligible in the atmosphere, the assumptions of the turbulence modelling are supported by atmospheric observations of large eddies which are highly elongated in a direction close to that of the geostrophic wind, together with the observed partitioning of turbulence energy between the large eddies and a distinctly smaller scale. The results indicate a strong sensitivity to the roll orientation, and also the presence of a slow variation on the Coriolis timescale.