A Conceptual View on Inertial Oscillations and Nocturnal Low-Level JetsSource: Journal of the Atmospheric Sciences:;2010:;Volume( 067 ):;issue: 008::page 2679Author:Van de Wiel, B. J. H.
,
Moene, A. F.
,
Steeneveld, G. J.
,
Baas, P.
,
Bosveld, F. C.
,
Holtslag, A. A. M.
DOI: 10.1175/2010JAS3289.1Publisher: American Meteorological Society
Abstract: In the present work Blackadar?s concept of nocturnal inertial oscillations is extended. Blackadar?s concept describes frictionless inertial oscillations above the nocturnal inversion layer. The current work includes frictional effects within the nocturnal boundary layer. It is shown that the nocturnal wind speed profile describes an oscillation around the nocturnal equilibrium wind vector, rather than around the geostrophic wind vector (as in the Blackadar case). By using this perspective, continuous time-dependent wind profiles are predicted. As such, information on both the height and the magnitude of the nocturnal low-level jet is available as a function of time. Preliminary analysis shows that the proposed extension performs well in comparison with observations when a simple Ekman model is used to represent the equilibrium state in combination with a realistic initial velocity profile. In addition to jet dynamics, backward inertial oscillations are predicted at lower levels close to the surface, which also appear to be present in observations. The backward oscillation forms an important mechanism behind weakening low-level winds during the afternoon transition. Both observational and theoretical modeling studies are needed to explore this phenomenon further.
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contributor author | Van de Wiel, B. J. H. | |
contributor author | Moene, A. F. | |
contributor author | Steeneveld, G. J. | |
contributor author | Baas, P. | |
contributor author | Bosveld, F. C. | |
contributor author | Holtslag, A. A. M. | |
date accessioned | 2017-06-09T16:34:13Z | |
date available | 2017-06-09T16:34:13Z | |
date copyright | 2010/08/01 | |
date issued | 2010 | |
identifier issn | 0022-4928 | |
identifier other | ams-70165.pdf | |
identifier uri | http://onlinelibrary.yabesh.ir/handle/yetl/4211916 | |
description abstract | In the present work Blackadar?s concept of nocturnal inertial oscillations is extended. Blackadar?s concept describes frictionless inertial oscillations above the nocturnal inversion layer. The current work includes frictional effects within the nocturnal boundary layer. It is shown that the nocturnal wind speed profile describes an oscillation around the nocturnal equilibrium wind vector, rather than around the geostrophic wind vector (as in the Blackadar case). By using this perspective, continuous time-dependent wind profiles are predicted. As such, information on both the height and the magnitude of the nocturnal low-level jet is available as a function of time. Preliminary analysis shows that the proposed extension performs well in comparison with observations when a simple Ekman model is used to represent the equilibrium state in combination with a realistic initial velocity profile. In addition to jet dynamics, backward inertial oscillations are predicted at lower levels close to the surface, which also appear to be present in observations. The backward oscillation forms an important mechanism behind weakening low-level winds during the afternoon transition. Both observational and theoretical modeling studies are needed to explore this phenomenon further. | |
publisher | American Meteorological Society | |
title | A Conceptual View on Inertial Oscillations and Nocturnal Low-Level Jets | |
type | Journal Paper | |
journal volume | 67 | |
journal issue | 8 | |
journal title | Journal of the Atmospheric Sciences | |
identifier doi | 10.1175/2010JAS3289.1 | |
journal fristpage | 2679 | |
journal lastpage | 2689 | |
tree | Journal of the Atmospheric Sciences:;2010:;Volume( 067 ):;issue: 008 | |
contenttype | Fulltext |