Buoyancy-Driven Flows

461 Pages·2012·35.644 MB·English

by  Eric P. Chassignet

BUOYANCY-DRIVEN FLOWS
Buoyancy is one of the main forces driving flows on our planet, especially in the oceans
and atmosphere.These flows range from buoyant coastal currents to dense overflows in the
ocean, and from avalanches to volcanic pyroclastic flows on the Earth’s surface. This book
bringstogethercontributionsbyleadingworldscientiststosummarizeourpresenttheoretical,
observational,experimental,andmodelingunderstandingofbuoyancy-drivenflows.
Thisbookstronglyemphasizestheocean,whichdisplaysanexceptionallywiderangeof
buoyancy-driven flows. Buoyancy-driven currents play a key role in the global ocean cir-
culation and in climate variability through their impact on deep-water formation. Correctly
representing buoyancy-driven processes not currently resolved in the ocean components of
climatemodelsisachallenge.Thelimitationsofcurrentmodelingtechniquesareexamined,
andrecommendationsaremadefortheproperphysicalparameterizationofbuoyancy-driven
processesinordertoaccuratelyprojectlong-termwatermassevolution.Buoyancy-drivencur-
rentsarealsoprimarilyresponsiblefortheredistributionoffreshwaterthroughouttheworld’s
oceans.Inadditiontofreshwater,buoyancy-drivenflowstransportheat,nutrients,sediments,
biogeochemicals, pollutants, and biological organisms along many continental shelves and
thushavesignificantimpactsonecosystems,fisheries,andthecoastalcirculation.
Thisbookisaninvaluableresourceforadvancedstudentsandresearchersinoceanography,
geophysical fluid dynamics, atmospheric science, and the wider Earth sciences who need a
state-of-the-artreferenceonbuoyancy-drivenflows.
eric p. chassignet
isprofessorintheDepartmentofEarth,Ocean,andAtmospheric
SciencesatFloridaStateUniversity,Tallahassee;directoroftheCenterforOcean-Atmospheric
PredictionStudies;andco-directoroftheFloridaClimateInstitute.Hewasawardedthe2008
NationalOceanographicPartnershipProgram’sExcellenceinPartneringAwardforhiscoordi-
nationoftheU.S.GlobalOceanDataAssimilationExperiment:GlobalOceanPredictionwith
thehybridCoordinateOceanModel(U.S.GODAEHYCOM).Dr.Chassignethaspublished
twopreviousbooksincollaborationwithDr.Verron:OceanModelingandParameterization
(1998)andOceanWeatherForecasting(2004).
claudia cenedese
is associate scientist with tenure in the Department of Physical
Oceanography at theWoods Hole Oceanographic Institution (WHOI), faculty of theWHOI
Geophysical Fluid Dynamics Summer Program, and co-director of the WHOI Geophysical
FluidDynamicsLaboratory.
jacques verron
isdirectorofresearchattheCentreNationaldeRechercheScientitifique
(CNRS);chiefscientistfortheFrance-IndiaSARAL/AltiKaaltimetricsatellitemission;and
formerdirectoroftheLaboratoiredesEcoulementsGéophysiquesetIndustrielsinGrenoble,
France.Dr.VerronwasawardedthesilvermedalfromtheCNRSin1994forhisworkonthe
developmentofoperationaloceanography.
drs. chassignet, cenedese, and verron
served as co-directors of the 2010
AlpineSummerSchoolonBuoyancy-DrivenFlowsheldinValsavarenche,Italy.
Published online by Cambridge University Press
Published online by Cambridge University Press
BUOYANCY-DRIVEN FLOWS
Editedby
ERIC P. CHASSIGNET
FloridaStateUniversity
CLAUDIA CENEDESE
WoodsHoleOceanographicInstitution
JACQUES VERRON
CentreNationaldelaRechercheScientifique
Published online by Cambridge University Press
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©CambridgeUniversityPress2012
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noreproductionofanypartmaytakeplacewithoutthewritten
permissionofCambridgeUniversityPress.
Firstpublished2012
PrintedintheUnitedStatesofAmerica
AcatalogrecordforthispublicationisavailablefromtheBritishLibrary.
LibraryofCongressCataloginginPublicationdata
Buoyancy-drivenflows/[editedby]EricChassignet,ClaudiaCenedese,JacquesVerron.
p. cm.
Includesbibliographicalreferencesandindex.
ISBN978-1-107-00887-8
1. Buoyantconvection. 2. Oceancirculation. 3. Atmosphericcirculation.
I. Chassignet,EricP. II. Cenedese,Claudia,1971– III. Verron,Jacques.
QC327.B862012
551.48–dc23 2011044342
ISBN978-1-107-00887-8Hardback
CambridgeUniversityPresshasnoresponsibilityforthepersistenceoraccuracyofURLsforexternalor
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Contents
ListofContributors page vii
Introduction 1
1 Gravitycurrents–theoryandlaboratoryexperiments 13
paul linden
2 Theoryofoceanicbuoyancy-drivenflows 52
joseph pedlosky
3 Buoyancy-forcedcirculationanddownwellinginmarginalseas 118
michael a. spall
4 Buoyantcoastalcurrents 164
steve lentz
5 Overflowsandconvectivelydrivenflows 203
sonya legg
6 Anoceanclimatemodelingperspectiveonbuoyancy-drivenflows 240
william g. large
7 Buoyancy-drivencurrentsineddyingoceanmodels 281
anne marie treguier, bruno ferron,
and raphael dussin
8 Atmosphericbuoyancy-drivenflows 312
sylvie malardel
9 Volcanicflows 338
andy woods
10 Gravityflowonsteepslope 372
christophe ancey
Index 433
Colorplatesfollowpage232
v
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Published online by Cambridge University Press
Contributors
Christophe Ancey Ecole Polytechnique Fédérale de Lausanne, Lausanne,
Switzerland
Raphael Dussin Laboratoire de Physique des Océans, CNRS-IRD-Ifremer-UBO,
Brest,France
BrunoFerronLaboratoiredePhysiquedesOcéans,CNRS-IRD-Ifremer-UBO,Brest,
France
WilliamG.LargeNationalCenterforAtmosphericResearch,Boulder,CO,USA
Sonya Legg Atmosphere and Ocean Science Program, Princeton University,
Princeton,USA
SteveLentzWoodsHoleOceanographicInstitution,WoodsHole,MA,USA
PaulLindenDepartmentofAppliedMathematicsandTheoreticalPhysics,University
ofCambridge,Cambridge,UK
SylvieMalardelMeteo-France,Toulouse,France,andECMWF,Reading,UK
JosephPedloskyWoodsHoleOceanographicInstitute,WoodsHole,MA,USA
MichaelA.SpallWoodsHoleOceanographicInstitute,WoodsHole,MA,USA
Anne Marie Treguier Laboratoire de Physique des Océans, CNRS-IRD-Ifremer-
UBO,Brest,France
AndyWoodsBPInstitute,UniversityofCambridge,Cambridge,UK
vii
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Published online by Cambridge University Press
Introduction
Buoyancyisoneofthemainforcesdrivingflowsonourplanetandbuoyancy-driven
flows encompass a wide spectrum of geophysical flows. In this book, contributions
by leading world scientists summarize our present theoretical, observational, exper-
imental, and modeling understanding of buoyancy-driven flows. These flows range
frombuoyantcoastalcurrentstodenseoverflowsintheocean,andfromavalanchesto
volcanicpyroclasticflowsontheEarth’ssurface.Bydesign,thereisastrongemphasis
on the ocean where a wide range of buoyancy-driven flows is observed. Buoyancy-
drivencurrentsplayakeyroleintheglobaloceancirculationandinclimatevariability
through deep-water formation. Formation of dense water usually occurs in marginal
seas, which are either cooler (at high latitudes) or saltier (due to greater evaporation
rates). These dense waters enter the ocean as a gravity-driven current, entrain sur-
roundingwatersastheydescendalongthecontinentalslope,andmodifytheocean’s
stratificationastheybecomepartoftheglobaloceancirculation.Buoyancy-drivencur-
rentsarealsoprimarilyresponsiblefortheredistributionoffreshwaterthroughoutthe
world’soceans.Inparticular,buoyantcoastalcurrentstransportfreshwater,heat,nutri-
ents, sediments, biogeochemicals, pollutants, and biological organisms along many
continental shelves and thus have significant impacts on ecosystems, fisheries, and
coastalcirculation.
In our examination of oceanic buoyancy-driven flows, we first provide a broad
overview of our current understanding of these flows from observations, laboratory
experiments, and idealized model configurations (Chapters 1–5). This is followed
by an in-depth discussion on the importance of correctly representing processes in
buoyancy-driven flows that are not currently resolved in the ocean component of
climatemodels(Chapter6)andonthedifficultyofproperlyrepresentingtheseflows
ineddy-resolvingoceanmodels(Chapter7).Finally,oceanicbuoyancy-drivenflows
are put in the context of a wider range of geophysical problems (atmospheric flows,
volcanicflows,andavalanches;Chapters8–10).
1
https://doi.org/10.1017/CBO9780511920196.001 Published online by Cambridge University Press