Laboratory experiments on stability and entrainment of oceanic stratocumulus. Part 2: Entrainment experiment
A stratified interface is stable to the buoyancy reversal instability for surprisingly large values of D (buoyancy reversal parameter). A new instability mechanism is proposed, which considers the mixing process at the interface. For the type of density curves studied here, under strong perturbation...
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ftnasantrs:oai:casi.ntrs.nasa.gov:19900018948 2023-05-15T13:37:34+02:00 Laboratory experiments on stability and entrainment of oceanic stratocumulus. Part 2: Entrainment experiment Shy, Shenqyang S. Unclassified, Unlimited, Publicly available Jul 1, 1990 application/pdf http://hdl.handle.net/2060/19900018948 unknown Document ID: 19900018948 Accession ID: 90N28264 http://hdl.handle.net/2060/19900018948 No Copyright CASI METEOROLOGY AND CLIMATOLOGY NASA, Langley Research Center, FIRE Science Results 1989; p 235-239 1990 ftnasantrs 2019-07-21T09:12:00Z A stratified interface is stable to the buoyancy reversal instability for surprisingly large values of D (buoyancy reversal parameter). A new instability mechanism is proposed, which considers the mixing process at the interface. For the type of density curves studied here, under strong perturbations, the mixed parcel must have a buoyancy reversal comparable to the initial stratification before the interface is unstable. This is in accord with a simple model of the interface mixing process, as well as aircraft observations of long-live marine stratocumulus clouds. These clouds' remarkable longevity in the face of finite D indicates that they can be stable (Hanson, 1984; Albrecht et al., 1985; Siems et al., 1989). It is suggested that buoyancy reversal as well as the disturbance must be large for Cloudtop Entrainment Stability. The effect of buoyancy reversal (evaporative cooling) does not always enhance the entrainment rate over that in the inert case, but it may be negligible if Ri (Richardson number) is large (Ri is larger than 50) and D is small (D is smaller than 0.5). This work may shed some light on the fundamental mechanism of the breakup process of the subtropical stratocumulus clouds into tradewind cumulus. These results may also be related to the instability in the Weddell Sea off of Antarctica. Other/Unknown Material Antarc* Antarctica Weddell Sea NASA Technical Reports Server (NTRS) Weddell Weddell Sea |
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NASA Technical Reports Server (NTRS) |
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ftnasantrs |
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topic |
METEOROLOGY AND CLIMATOLOGY |
spellingShingle |
METEOROLOGY AND CLIMATOLOGY Shy, Shenqyang S. Laboratory experiments on stability and entrainment of oceanic stratocumulus. Part 2: Entrainment experiment |
topic_facet |
METEOROLOGY AND CLIMATOLOGY |
description |
A stratified interface is stable to the buoyancy reversal instability for surprisingly large values of D (buoyancy reversal parameter). A new instability mechanism is proposed, which considers the mixing process at the interface. For the type of density curves studied here, under strong perturbations, the mixed parcel must have a buoyancy reversal comparable to the initial stratification before the interface is unstable. This is in accord with a simple model of the interface mixing process, as well as aircraft observations of long-live marine stratocumulus clouds. These clouds' remarkable longevity in the face of finite D indicates that they can be stable (Hanson, 1984; Albrecht et al., 1985; Siems et al., 1989). It is suggested that buoyancy reversal as well as the disturbance must be large for Cloudtop Entrainment Stability. The effect of buoyancy reversal (evaporative cooling) does not always enhance the entrainment rate over that in the inert case, but it may be negligible if Ri (Richardson number) is large (Ri is larger than 50) and D is small (D is smaller than 0.5). This work may shed some light on the fundamental mechanism of the breakup process of the subtropical stratocumulus clouds into tradewind cumulus. These results may also be related to the instability in the Weddell Sea off of Antarctica. |
format |
Other/Unknown Material |
author |
Shy, Shenqyang S. |
author_facet |
Shy, Shenqyang S. |
author_sort |
Shy, Shenqyang S. |
title |
Laboratory experiments on stability and entrainment of oceanic stratocumulus. Part 2: Entrainment experiment |
title_short |
Laboratory experiments on stability and entrainment of oceanic stratocumulus. Part 2: Entrainment experiment |
title_full |
Laboratory experiments on stability and entrainment of oceanic stratocumulus. Part 2: Entrainment experiment |
title_fullStr |
Laboratory experiments on stability and entrainment of oceanic stratocumulus. Part 2: Entrainment experiment |
title_full_unstemmed |
Laboratory experiments on stability and entrainment of oceanic stratocumulus. Part 2: Entrainment experiment |
title_sort |
laboratory experiments on stability and entrainment of oceanic stratocumulus. part 2: entrainment experiment |
publishDate |
1990 |
url |
http://hdl.handle.net/2060/19900018948 |
op_coverage |
Unclassified, Unlimited, Publicly available |
geographic |
Weddell Weddell Sea |
geographic_facet |
Weddell Weddell Sea |
genre |
Antarc* Antarctica Weddell Sea |
genre_facet |
Antarc* Antarctica Weddell Sea |
op_source |
CASI |
op_relation |
Document ID: 19900018948 Accession ID: 90N28264 http://hdl.handle.net/2060/19900018948 |
op_rights |
No Copyright |
_version_ |
1766094331073003520 |