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| Titel |
Turbulence structure of the boundary layer below marine clouds in the SOFIA experiment |
| VerfasserIn |
A. Réchou, P. Durand, A. Druilhet, B. Bénech |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 13, no. 10 ; Nr. 13, no. 10, S.1075-1086 |
| Datensatznummer |
250012009
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| Publikation (Nr.) |
 copernicus.org/angeo-13-1075-1995.pdf |
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| Zusammenfassung |
| The SOFIA (Surface of the Ocean: Flux and
Interaction with the Atmosphere) experiment, included in the ASTEX (Atlantic
Stratocumulus Transition Experiment) field program, was conducted in June 1992
in the Azores region in order to investigate air-sea exchanges, as well as the
structure of the atmospheric boundary layer and its capping low-level cloud
cover. We present an analysis of the vertical structure of the marine
atmospheric boundary layer (MABL), and especially of its turbulence
characteristics, deduced from the aircraft missions performed during SOFIA. The
meteorological situations were characteristic of a temperate latitude under
anticyclonic conditions, i.e., with weak to moderate winds, weak surface
sensible heat flux, and broken capping low-altitude cloud cover topped by a
strong trade inversion. We show that the mixed layer, driven by the surface
fluxes, is decoupled from the above cloud layer. Although weak, the surface
buoyancy flux, and the convective velocity scale deduced from it, are relevant
for scaling the turbulence moments. The mixed layer then follows the behaviour
of a continental convective boundary layer, with the exception of the
entrainment process, which is weak in the SOFIA data. These results are
confirmed by conditional sampling analysis, which shows that the major
turbulence source lies in the buoyant moist updrafts at the surface. |
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