The Structure of the Near-Neutral Atmospheric Surface LayerSource: Journal of the Atmospheric Sciences:;2004:;Volume( 061 ):;issue: 006::page 699Author:Drobinski, Philippe
,
Carlotti, Pierre
,
Newsom, Rob K.
,
Banta, Robert M.
,
Foster, Ralph C.
,
Redelsperger, Jean-Luc
DOI: 10.1175/1520-0469(2004)061<0699:TSOTNA>2.0.CO;2Publisher: American Meteorological Society
Abstract: Recent observational data (turbulence variables by sonic anemometers and three-dimensional flow pattern by Doppler lidar), obtained during the Cooperative Atmosphere Surface Exchange Study field campaign in October 1999 (CASES-99), show evidence of a layered structure of the near-neutral surface layer: (i) the eddy surface layer (ESL), which is the lower sublayer where blocking of impinging eddies is the dominating mechanism; and (ii) the shear surface layer (SSL), which is an intermediate sublayer, where shear affects the isotropy of turbulence. The origin of the eddies impinging from aloft (probably from the SSL) down to the ESL is preliminarily addressed in this study, since the Doppler lidar data show evidence of linearly organized eddies embedded in the surface layer (i.e., about 100-m vertical extent) and horizontally spaced by about 300 m. This is consistent with theories predicting that the primary mechanism of eddy motion in high Reynolds number wall layers is ?top-down.? The layered structure of the surface layer also has a visible effect on vertical profiles of vertical velocity variance (w2) and momentum transport. In the ESL, w2 scales as z2/3 while it is constant or slightly decreases within the SSL. Concerning momentum transport, ejections contribute identically to the momentum flux as do sweeps in the ESL, whereas in the SSL, ejections give about 50% higher relative contribution.
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contributor author | Drobinski, Philippe | |
contributor author | Carlotti, Pierre | |
contributor author | Newsom, Rob K. | |
contributor author | Banta, Robert M. | |
contributor author | Foster, Ralph C. | |
contributor author | Redelsperger, Jean-Luc | |
date accessioned | 2017-06-09T14:38:38Z | |
date available | 2017-06-09T14:38:38Z | |
date copyright | 2004/03/01 | |
date issued | 2004 | |
identifier issn | 0022-4928 | |
identifier other | ams-23437.pdf | |
identifier uri | http://onlinelibrary.yabesh.ir/handle/yetl/4159998 | |
description abstract | Recent observational data (turbulence variables by sonic anemometers and three-dimensional flow pattern by Doppler lidar), obtained during the Cooperative Atmosphere Surface Exchange Study field campaign in October 1999 (CASES-99), show evidence of a layered structure of the near-neutral surface layer: (i) the eddy surface layer (ESL), which is the lower sublayer where blocking of impinging eddies is the dominating mechanism; and (ii) the shear surface layer (SSL), which is an intermediate sublayer, where shear affects the isotropy of turbulence. The origin of the eddies impinging from aloft (probably from the SSL) down to the ESL is preliminarily addressed in this study, since the Doppler lidar data show evidence of linearly organized eddies embedded in the surface layer (i.e., about 100-m vertical extent) and horizontally spaced by about 300 m. This is consistent with theories predicting that the primary mechanism of eddy motion in high Reynolds number wall layers is ?top-down.? The layered structure of the surface layer also has a visible effect on vertical profiles of vertical velocity variance (w2) and momentum transport. In the ESL, w2 scales as z2/3 while it is constant or slightly decreases within the SSL. Concerning momentum transport, ejections contribute identically to the momentum flux as do sweeps in the ESL, whereas in the SSL, ejections give about 50% higher relative contribution. | |
publisher | American Meteorological Society | |
title | The Structure of the Near-Neutral Atmospheric Surface Layer | |
type | Journal Paper | |
journal volume | 61 | |
journal issue | 6 | |
journal title | Journal of the Atmospheric Sciences | |
identifier doi | 10.1175/1520-0469(2004)061<0699:TSOTNA>2.0.CO;2 | |
journal fristpage | 699 | |
journal lastpage | 714 | |
tree | Journal of the Atmospheric Sciences:;2004:;Volume( 061 ):;issue: 006 | |
contenttype | Fulltext |