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Roles of drizzle in a one-dimensional third-order turbulence closure model of the nocturnal stratus-topped marine boundary layerThis study focuses on the effects of drizzle in a one-dimensional third-order turbulence closure model of the nocturnal stratus-topped marine boundary layer. When the simulated drizzle rate is relatively small (maximum approximately equal to 0.6 mm/day), steady-state solutions are obtained. The boundary layer stabilizes essentially because drizzle causes evaporative cooling of the subcloud layer. This stabilization considerably reduces the buoyancy flux and turbulence kinetic energy below the stratus cloud. Thus, drizzle tends to decouple the cloud from the subcloud layer in the model, as suggested by many observational studies. In addition, the evaporation of drizzle in the subcloud layer creates small scattered clouds, which are likely to represent cumulus clouds, below the solid stratus cloud in the model. The sensitivity experiments show that these scattered clouds help maintain a coupled boundary layer. When the drizzle rate is relatively large (maximum approximately equal to 0.9 mm/day), the response of the model becomes transient with bursts in turbulent fluxes. This phenomenon is related to the formation of the scattered cloud layer below the solid stratus cloud. It appears that the model is inadequate to represent the heat and moisture transport by strong updrafts covering a small fractional area in cumulus convection.
Document ID
19950028643
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Wang, Shouping
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Wang, Qing
(National Center for Atmospheric Research, Boulder, CO United States)
Date Acquired
August 16, 2013
Publication Date
June 1, 1994
Publication Information
Publication: Journal of the Atmospheric Sciences
Volume: 51
Issue: 11
ISSN: 0022-4928
Subject Category
Meteorology And Climatology
Accession Number
95A60242
Funding Number(s)
CONTRACT_GRANT: NSF-ATM-89-09947
CONTRACT_GRANT: NAS8-39231
CONTRACT_GRANT: ONR-N00014-91-1992
Distribution Limits
Public
Copyright
Other

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