Open AccessObservations of marine stratocumulus microphysics and implications for processes controlling droplet spectra: Results from the Marine Stratus/Stratocumulus Experiment
Author(s) -
Wang Jian,
Daum Peter H.,
Yum Seong Soo,
Liu Yangang,
Senum Gunnar I.,
Lu MiaoLing,
Seinfeld John H.,
Jonsson Haflidi
Publication year - 2009
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 - 10.1029/2008jd011035
Subject(s) - marine stratocumulus , drizzle , atmospheric sciences , environmental science , aerosol , liquid water path , liquid water content , mixing (physics) , mixing ratio , sea salt aerosol , entrainment (biomusicology) , cloud condensation nuclei , altitude (triangle) , meteorology , precipitation , geology , cloud computing , physics , sea salt , geometry , mathematics , quantum mechanics , computer science , rhythm , acoustics , operating system
During the Marine Stratus/Stratocumulus Experiment, cloud and aerosol microphysics were measured in the eastern Pacific off the coast of northern California on board Department of Energy Gulfstream‐1 in July 2005. Three cases with uniform aerosol concentration and minimal drizzle concentration were examined to study cloud microphysical behavior. For these three cases, the average droplet number concentration increased with increasing altitude, while the average interstitial aerosol concentration decreased with altitude. The data show enhanced growth of large droplets and spectral broadening in cloud parcels with low liquid water mixing ratio. Three mixing models, including inhomogeneous mixing, entity type entrainment mixing, and circulation mixing proposed in this study, are examined with regard to their influences on cloud microphysics. The observed cloud microphysical behavior is most consistent with the circulation mixing, which describes the mixing between cloud parcels with different lifting condensation levels during their circulations driven by evaporative and radiative cooling. The enhanced growth and spectrum broadening resulting from the circulation mixing reduce cloud albedo at the same liquid water path and facilitate the formation of precipitation embryos.