Open AccessA single‐column model intercomparison of a heavily drizzling stratocumulus‐topped boundary layer
Author(s) -
Wyant Matthew C.,
Bretherton Christopher S.,
Chlond Andreas,
Griffin Brian M.,
Kitagawa Hiroto,
Lappen CaraLyn,
Larson Vincent E.,
Lock Adrian,
Park Sungsu,
de Roode Stephan R.,
Uchida Junya,
Zhao Ming,
Ackerman Andrew S.
Publication year - 2007
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2007jd008536
Subject(s) - drizzle , marine stratocumulus , environmental science , entrainment (biomusicology) , liquid water path , atmospheric sciences , boundary layer , meteorology , cloud base , planetary boundary layer , climatology , turbulence , aerosol , geology , physics , cloud computing , mechanics , precipitation , rhythm , acoustics , computer science , operating system
This study presents an intercomparison of single‐column model simulations of a nocturnal heavily drizzling marine stratocumulus‐topped boundary layer. Initial conditions and forcings are based on nocturnal flight observations off the coast of California during the DYCOMS‐II field experiment. Differences in turbulent and microphysical parameterizations between models were isolated by slightly idealizing and standardizing the specification of surface and radiative fluxes. For most participating models, the case was run at both typical operational vertical resolution of about 100 m and also at high vertical resolution of about 10 m. As in prior stratocumulus intercomparisons, the simulations quickly develop considerable scatter in liquid water path (LWP) between models. However, the simulated dependence of cloud base drizzle fluxes on LWP in most models is broadly consistent with recent observations. Sensitivity tests with drizzle turned off show that drizzle substantially decreases LWP for many models. The sensitivity of entrainment rate to drizzle is more muted. Simulated LWP and entrainment are also sensitive to the inclusion of cloud droplet sedimentation. Many models underestimate the fraction of drizzle that evaporates below cloud base, which may distort the simulated feedbacks of drizzle on turbulence, entrainment, and LWP.