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dc.contributor.authorChen, Gang
dc.contributor.authorPlumb, R. Alan
dc.date.accessioned2015-04-02T17:18:06Z
dc.date.available2015-04-02T17:18:06Z
dc.date.issued2014-09
dc.date.submitted2014-05
dc.identifier.issn0022-4928
dc.identifier.issn1520-0469
dc.identifier.urihttp://hdl.handle.net/1721.1/96339
dc.description.abstractTropospheric transport can be described qualitatively by the slow mean diabatic circulation and rapid isentropic mixing, yet a quantitative understanding of the transport circulation is complicated, as nearly half of the isentropic surfaces in the troposphere frequently intersect the ground. A theoretical framework for the effective isentropic diffusivity of tropospheric transport is presented. Compared with previous isentropic analysis of effective diffusivity, a new diagnostic is introduced to quantify the eddy diffusivity of the near-surface isentropic flow. This diagnostic also links the effective eddy diffusivity directly to a diffusive closure of eddy fluxes through a finite-amplitude wave activity equation. The theory is examined in a dry primitive equation model on the sphere. It is found that the upper troposphere is characterized by a diffusivity minimum at the jet’s center with enhanced mixing at the jet’s flanks and that the lower troposphere is dominated by stronger mixing throughout the baroclinic zone. This structure of isentropic diffusivity is generally consistent with the diffusivity obtained from the geostrophic component of the flow. Furthermore, the isentropic diffusivity agrees broadly with the tracer equivalent length obtained from either a spectral diffusion scheme or a semi-Lagrangian advection scheme, indicating that the effective diffusivity of tropospheric transport is largely dictated by large-scale stirring rather than details of the small-scale diffusion acting on the tracers.en_US
dc.language.isoen_US
dc.publisherAmerican Meteorological Societyen_US
dc.relation.isversionofhttp://dx.doi.org/10.1175/jas-d-13-0333.1en_US
dc.rightsArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.en_US
dc.sourceAmerican Meteorological Societyen_US
dc.titleEffective Isentropic Diffusivity of Tropospheric Transporten_US
dc.typeArticleen_US
dc.identifier.citationChen, Gang, and Alan Plumb. “Effective Isentropic Diffusivity of Tropospheric Transport.” J. Atmos. Sci. 71, no. 9 (September 2014): 3499–3520. © 2014 American Meteorological Societyen_US
dc.contributor.departmentMassachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciencesen_US
dc.contributor.departmentMassachusetts Institute of Technology. Program in Atmospheres, Oceans, and Climateen_US
dc.contributor.mitauthorPlumb, R. Alanen_US
dc.relation.journalJournal of the Atmospheric Sciencesen_US
dc.eprint.versionFinal published versionen_US
dc.type.urihttp://purl.org/eprint/type/JournalArticleen_US
eprint.statushttp://purl.org/eprint/status/PeerRevieweden_US
dspace.orderedauthorsChen, Gang; Plumb, Alanen_US
dc.identifier.orcidhttps://orcid.org/0000-0002-6716-1576
mit.licensePUBLISHER_POLICYen_US


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