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dc.contributor.authorRissman, T.A.
dc.contributor.authorVarutbangkul, V.
dc.contributor.authorJonsson, H.H.
dc.contributor.authorNenes, A.
dc.contributor.authorJimenez, J.L.
dc.contributor.authorDelia, A.E.
dc.contributor.authorBahreini, R.
dc.contributor.authorRoberts, G.C.
dc.contributor.authorSeinfled, J.H.
dc.contributor.authorConant, W. C.
dc.contributor.authorVan Reken, T.M.
dc.date2004
dc.date.accessioned2014-06-11T23:18:31Z
dc.date.available2014-06-11T23:18:31Z
dc.date.issued2004
dc.identifier.urihttp://hdl.handle.net/10945/42212
dc.descriptionJournal of Geophysical Research, Vol. 109, D13204en_US
dc.descriptionThe article of record as published may be located at http://dx.doi.org/10.1029/2003JD004324en_US
dc.description.abstractOur understanding of the activation of aerosol particles into cloud drops during the formation of warm cumulus clouds presently has a limited observational foundation. Detailed observations of aerosol size and composition, cloud microphysics and dynamics, and atmospheric thermodynamic state were collected in a systematic study of 21 cumulus clouds by the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft during NASA’s Cirrus Regional Study of Tropical Anvils and Cirrus Layers–Florida Area Cirrus Experiment (CRYSTAL-FACE). An ‘‘aerosol-cloud’’ closure study was carried out in which a detailed cloud activation parcel model, which predicts cloud drop concentration using observed aerosol concentration, size distribution, cloud updraft velocity, and thermodynamic state, is evaluated against observations. On average, measured droplet concentration in adiabatic cloud regions is within 15% of the predictions. This agreement is corroborated by independent measurements of aerosol activation carried out by two cloud condensation nucleus (CCN) counters on the aircraft. Variations in aerosol concentration, which ranged from 300 to 3300 cm 3, drives large microphysical differences (250– 2300 cm 3) observed among continental and maritime clouds in the South Florida region. This is the first known study in which a cloud parcel model is evaluated in a closure study using a constraining set of data collected from a single platform. Likewise, this is the first known study in which relationships among aerosol size distribution, CCN spectrum, and cloud droplet concentration are all found to be consistent with theory within experimental uncertainties much less than 50%. Vertical profiles of cloud microphysical properties (effective radius, droplet concentration, dispersion) clearly demonstrate the boundary layer aerosol’s effect on cloud microphysics throughout the lowest 1 km of cloud depth. Onboard measurements of aerosol hygroscopic growth and the organic to sulfate mass ratio are related to CCN properties. These chemical data are used to quantify the range of uncertainty associated with the simplified treatment of aerosol composition assumed in the closure study.en_US
dc.rightsThis publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. As such, it is in the public domain, and under the provisions of Title 17, United States Code, Section 105, may not be copyrighted.en_US
dc.titleAerosol-Cloud drop concentration closure in warm cumulusen_US
dc.contributor.departmentCenter for Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS)
dc.subject.authoraerosolen_US
dc.subject.authorCCNen_US
dc.subject.authorcloud microphysicsen_US


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