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dc.contributor.advisorvan den Heever, Susan C.
dc.contributor.authorSheffield, Amanda M.
dc.contributor.committeememberKreidenweis, Sonia
dc.contributor.committeememberEykholt, Richard
dc.date.accessioned2007-01-03T08:22:06Z
dc.date.available2007-01-03T08:22:06Z
dc.date.issued2011
dc.description2011 Fall.
dc.descriptionIncludes bibliographical references.
dc.description.abstractCumulus congestus clouds are mid-level clouds that form part of the trimodal tropical cloud distribution. They act to moisten the atmosphere and may become mixed-phase in their lifetime. Congestus typically surpass the tropical trade wind inversion from where they may either develop into deeper convection, or alternatively remain as terminal congestus. Such growth is dependent on multiple factors, including those which alter the local environment and the microphysical structure of the cloud. This study investigates the impacts of cloud condensation nuclei (CCN) on cumulus congestus clouds through the use of large domain, cloud-resolving model (CRM) simulations in radiative convective equilibrium (RCE). Previous studies have focused on the convective invigoration of congestus and their subsequent growth to deep convection in association with ice processes. This study will focus on the response of congestus clouds to more polluted conditions, with particular emphasis on the development and growth of congestus from the warm phase to beyond the freezing level. It is found that convection is invigorated in the more polluted cases in association with the enhanced latent heat released during the vapor diffusional growth of cloud droplets in the warm phase. Such invigoration results in stronger updraft speeds, enhanced vertical lofting of cloud water, and a subsequent increase in the number of clouds growing to above the freezing level. The lofted cloud water is available to form more ice, however the ice water produced is smaller in magnitude compared to cloud water amounts above the freezing level. The low amounts of ice result in relatively insignificant contributions of the latent heat of freezing to the updraft strength. The impacts of enhanced CCN concentrations on various other cloud characteristics and microphysical processes are also investigated.
dc.format.mediumborn digital
dc.format.mediummasters theses
dc.identifierSheffield_colostate_0053N_10856.pdf
dc.identifierETDF2011400325ATMS
dc.identifier.urihttp://hdl.handle.net/10217/70827
dc.languageEnglish
dc.publisherColorado State University. Libraries
dc.relation.ispartof2000-2019 - CSU Theses and Dissertations
dc.rightsCopyright of the original work is retained by the author.
dc.titleAssessing the impacts of cloud condensation nuclei on cumulus congestus clouds using a cloud resolving model
dc.typeText
dcterms.rights.dplaThe copyright and related rights status of this item has not been evaluated (https://rightsstatements.org/vocab/CNE/1.0/). Please refer to the organization that has made the Item available for more information.
thesis.degree.disciplineAtmospheric Science
thesis.degree.grantorColorado State University
thesis.degree.levelMasters
thesis.degree.nameMaster of Science (M.S.)


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