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Cloud transitions and decoupling in shear‐free stratocumulus‐topped boundary layers
Author(s) -
Stevens Bjorn
Publication year - 2000
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/1999gl011257
Subject(s) - buoyancy , convection , convective boundary layer , decoupling (probability) , mechanics , entrainment (biomusicology) , boundary layer , geology , marine stratocumulus , large eddy simulation , planetary boundary layer , geophysics , meteorology , physics , turbulence , aerosol , control engineering , rhythm , acoustics , engineering
Large‐eddy simulations of shear‐free stratocumulus‐topped layers tend strongly toward a two‐layer structure as the negative area in the buoyancy flux profile that would be necessary to maintain a mixed layer increases to more than 10% of the positive area. In addition to identifying a threshold for what amounts to a convective transition, the simulations provide further evidence that a commonly used entrainment closure is ill‐founded. Lastly the simulations demonstrate that attempts to formulate a similarity theory for convective layers must account for the geometry of the buoyancy‐flux profile, and not simply its integral.