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Dynamics in the Anvil Outflow of Tropical Convection

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dc.contributor.advisorPagiatakis, Spiros D.
dc.creatorLederman, Jerusha Isabel
dc.date.accessioned2015-08-28T15:27:17Z
dc.date.available2015-08-28T15:27:17Z
dc.date.copyright2015-01-13
dc.date.issued2015-08-28
dc.date.updated2015-08-28T15:27:17Z
dc.degree.disciplineEarth & Space Science
dc.degree.levelDoctoral
dc.degree.namePhD - Doctor of Philosophy
dc.description.abstractThis thesis presents results of an experiment to investigate the dynamics of air motions within the outflow of tropical deep convection in the upper troposphere above Darwin, Australia. The research involved analyzing in situ measurements within the anvil outflow from the Egrett aircraft and also coincident laser remote sensing measurements of cloud structure from a King Air aircraft, flying directly below the Egrett. The data included the only in situ turbulence measurements that have been obtained with a resolution of 4 meters inside of an anvil outflow. The research shows that gravity waves and coherent structures exist in the anvil outflow. High frequency gravity waves were identified from the 90ᵒ phase lag between temperature and vertical wind oscillations. The gravity waves had wavelengths of 2 – 5 km and were observed as isolated waves with less than two oscillations, or, as extended waves with several oscillations. In some instances, correlations between temperature and vertical wind oscillations had zero phase lag between them and this was consistent with Rayleigh-Bénard convective rolls. Turbulence in the outflow was observed to be intense within patches separated by more quiescent flow. This turbulence had some characteristics that were unique in comparison to previous turbulence measurements at similar altitudes in the jet stream or midlatitude cirrus clouds. The ratio of the power spectral density of vertical wind fluctuations to the horizontal wind fluctuations was greater in the anvil outflow in comparison to the measurements in turbulence generated by shear in mid latitude jet stream and cirrus clouds. The relative magnitude of the vertical wind fluctuation spectrum decreases at all wavelengths with increasing distance away from the core region of the storm. This constitutes the first evidence that is consistent with theoretical predictions of “stratified turbulence.” Measurements in flights above and below the outflow base indicate that momentum flux is directed both upward and downward, away from the cloud base. This suggests the combination of shear and undulations in the cloud base are a mechanism for generating the observed high frequency gravity waves. This mechanism has not been previously identified from measurements or theoretical modelling and thus adds to our knowledge of processes that transport constituents and momentum within the tropical upper troposphere.
dc.identifier.urihttp://hdl.handle.net/10315/30028
dc.language.isoen
dc.rightsAuthor owns copyright, except where explicitly noted. Please contact the author directly with licensing requests.
dc.subjectAtmospheric sciences
dc.subjectPhysics
dc.subjectMeteorology
dc.subject.keywordsIsolated wave
dc.subject.keywordsIsolated waves
dc.subject.keywordsGravity wave
dc.subject.keywordsGravity waves
dc.subject.keywordsDeep convection
dc.subject.keywordsConvective roll
dc.subject.keywordsHorizontal convective roll
dc.subject.keywordsHCR
dc.subject.keywordsConvective rolls
dc.subject.keywordsAnvil
dc.subject.keywordsCirrus
dc.subject.keywordsCirrus clouds
dc.subject.keywordsAnvil outflow
dc.subject.keywordsAircraft safety
dc.subject.keywordsThunderstorm no fly zone
dc.subject.keywordsPlane
dc.subject.keywordsPlanes
dc.subject.keywordsFlight hazard
dc.subject.keywordsRayleigh-Benard convection
dc.subject.keywordsRayleigh-Benard
dc.subject.keywordsRankine vortex
dc.subject.keywordsOutflow
dc.subject.keywordsConvection
dc.subject.keywordsTropical
dc.subject.keywordsTropical convection
dc.subject.keywordsMaritime continent
dc.subject.keywordsTropopause
dc.subject.keywordsTroposphere
dc.subject.keywordsUpper Troposphere Lower Stratosphere
dc.subject.keywordsUTLS
dc.subject.keywordsAtmosphere
dc.subject.keywordsAtmospheric dynamics
dc.subject.keywordsDynamics
dc.subject.keywordsInstability
dc.subject.keywordsInstabilities
dc.subject.keywordsPhysics
dc.subject.keywordsAtmospheric physics
dc.subject.keywordsEMERALD
dc.subject.keywordsEMERALD 2
dc.subject.keywordsExperimental
dc.subject.keywordsCampaign
dc.subject.keywordsAirborne
dc.subject.keywordsAircraft
dc.subject.keywordsMeasurement
dc.subject.keywordsMeasurements
dc.subject.keywordsEgrett
dc.subject.keywordsKing Air
dc.subject.keywordsTurbulence
dc.subject.keywordsJerusha
dc.subject.keywordsJerusha Lederman
dc.subject.keywordsLederman
dc.subject.keywordsJim
dc.subject.keywordsWhiteway
dc.subject.keywordsJim Whiteway
dc.subject.keywordsStorm
dc.subject.keywordsTropical storm
dc.subject.keywordsHector
dc.subject.keywordsDarwin
dc.subject.keywordsAustralia
dc.subject.keywordsTiwi Islands
dc.subject.keywordsBathurst Island
dc.subject.keywordsMelville Island
dc.subject.keywordsIslands
dc.subject.keywordsSea-breeze circulation
dc.subject.keywordsSmall scale dynamics
dc.subject.keywordsLidar
dc.subject.keywordsRadar
dc.subject.keywordsBAT probe
dc.subject.keywordsTurbulence probe
dc.subject.keywordsLight detection and ranging
dc.subject.keywordsMeteorology
dc.subject.keywordsPlanetary science
dc.subject.keywordsScience
dc.subject.keywordsLaser
dc.subject.keywordsExperiment
dc.subject.keywordsStratified turbulence
dc.subject.keywordsMammatus
dc.subject.keywordsMammatus clouds
dc.subject.keywordsMamma
dc.subject.keywordsThunderstorm
dc.subject.keywordsLatent heat
dc.subject.keywordsWater vapor
dc.subject.keywordsVapor
dc.subject.keywordsVapour
dc.subject.keywordsClimate
dc.subject.keywordsMixing
dc.subject.keywordsAir
dc.subject.keywordsAir motions
dc.subject.keywordsWaves
dc.subject.keywordsWavelet
dc.subject.keywordsWavelets
dc.subject.keywordsDynamic
dc.subject.keywordsAnalysis
dc.subject.keywordsVertical velocity
dc.subject.keywordsPerturbation wind velocity
dc.subject.keywordsPerturbation vertical velocity
dc.subject.keywordsPotential temperature
dc.subject.keywordsCorrelations
dc.subject.keywordsWind temperature correlation
dc.subject.keywordsPhase
dc.subject.keywordsPhase relationship
dc.subject.keywordsQuasi-2d turbulence
dc.titleDynamics in the Anvil Outflow of Tropical Convection
dc.typeElectronic Thesis or Dissertationen_US

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