contributor author | Gawarkiewicz, Glen | |
contributor author | Chapman, David C. | |
date accessioned | 2017-06-09T14:50:04Z | |
date available | 2017-06-09T14:50:04Z | |
date copyright | 1991/08/01 | |
date issued | 1991 | |
identifier issn | 0022-3670 | |
identifier other | ams-27805.pdf | |
identifier uri | http://onlinelibrary.yabesh.ir/handle/yetl/4164851 | |
description abstract | A depth-averaged model with no density variations was used by Chapman to describe the formation of a passive tracer front at a shelfbreak. The relevance of this frontogenesis mechanism to cases that allow vertical variations is examined by considering the three-dimensional structure of a passive tracer front with explicit finite vertical mixing and bottom boundary layer dynamics. A three-dimensional primitive-equation numerical model is configured in a channel with a continental shelf, slope, and abyssal plain running the length of the channel. A vertically and horizontally uniform inflow is imposed over the shelf, with a large horizontal velocity shear near the shelfbreak. In the primitive-equation model, the offshore flow is concentrated in the bottom boundary layer while the alongshelf flow distribution is similar to the depth-averaged case; the presence of the bottom topography maintains a strong horizontal shear near the shelfbreak above the bottom boundary layer. This velocity shear causes a smooth passive tracer distribution imposed at the inflow boundary to develop strong cross-shelf gradients near the shelfbreak (i.e., a passive tracer front) within a rather short downstream distance, as in the depth-averaged model. Neutrally buoyant Lagrangian particles initialized above the bottom boundary layer are rapidly advected along the shelf with little cross-shelf motion. However, particles initialized within the bottom boundary layer move quickly offshore toward the shelfbreak and beyond while being advected alongshelf relatively slowly. The shelfbreak does not act as a barrier to the offshore transport of neutrally buoyant particles despite the presence of the passive tracer front. This results in a continuous net offshore transport from the shelf to the deep ocean due to the effects of bottom friction. | |
publisher | American Meteorological Society | |
title | Formation and Maintenance of Shelfbreak Fronts in an Unstratified Flow | |
type | Journal Paper | |
journal volume | 21 | |
journal issue | 8 | |
journal title | Journal of Physical Oceanography | |
identifier doi | 10.1175/1520-0485(1991)021<1225:FAMOSF>2.0.CO;2 | |
journal fristpage | 1225 | |
journal lastpage | 1239 | |
tree | Journal of Physical Oceanography:;1991:;Volume( 021 ):;issue: 008 | |
contenttype | Fulltext | |