Building theADCIRC CollaborativeA federated approach to storm surge modeling and model output distribution toenable better decision support

C O N T A C T I N F O R M A T I O N

Brian BlantonTelephone: 919.445.9620Email: brian_blanton@renci.org

A R E N C I W H I T E P A P E R

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At a Glance• Strongcoastalstorms,inthe

formoftropicalcyclonesandextra-tropicalstorms,causeenormousdamage.Accuratepredictionofastorm’sim-pactscanhelpsavelivesandreducepropertydamage.

• ADCIRCisapowerfulmodelthatpredictstheimpactsofstormsurgeandwaveac-tionassociatedwithcoastalstormsatalevelofdetailandaccuracynotavailablefromothermodelingsystems.

• AnADCIRCcollaborative—aworkingrelationshipamongresearchcenterswithADCIRCcapabilities—willalloweffec-tiveandefficientdeploymentofADCIRCtosupportreal-timestormpredictionandon-the-groundpreparednessandresponse.

The TeamWrittenbyBrian Blanton,RENCISeniorResearchScientistandOceanographer,withcontributionsfromRick Luettich,Director,UNCHazardsCenterandUNCInstituteofMarineSciences,Jessica Losego,UNCInstitutefortheEnvironment,andJason Fleming,PrincipalEngineeratSeahorseCoastalConsulting.Additionalwritingsup-portfromAnne Frances Johnson.

ContactBrianBlanton,919.445.9620brian_blanton@renci.org

Vol.1,No.1intheRENCIWhitePaperSeries,August2013RenaissanceComputingInstituteUniversityofNorthCarolinaatChapelHill919-445-9640www.renci.org@renci

Summary

Strongcoastalstorms,includingbothtropicalcyclones(e.g.,hurri-canes)andextra-tropicalstorms(e.g.,nor’easters)routinelythreatenhumanlivesandproperty.Overthepastdecade,16stormsstriking

theAtlanticcoasthavecausedmorethan$1billionindamageeach,withotherstormscostingmanyhundredsofmillionsmore.HurricaneKatrinain2005,oneofthemostdevastatinginU.S.history,caused1,833deathsand$125billionindamage(NationalClimaticDataCenter2013).Muchofthedamagefromsuchstormscomesfromfloodingduetostormsurge(anabnormalriseinoceanwatercausedbyacoastalstorm),anddestructioncausedbylargewind-generatedwaves.

Accurate,detailed,andrapidstormpredictionscanhelpsavelivesandpreventpropertydamagebyinformingevacuationsandotheremergencypreparednessandresponseactivities.Stormimpactmodelsarealsocriti-caltolong-termplanningforcoastaldevelopment,infrastructure,andinsurance.Currentmodelsusedtopredictstormimpactsrequiretrade-offsbetweendetail,accuracy,andspeed.ADCIRCisapowerfulmodelthatspecializesinpredictingtheresponseofthecoastalocean,includingstormsurgeandwaveaction,causedbycoastalstorms.AlthoughADCIRCisbeingdeployedatseveralmajorresearchcentersandhasprovedhighlyvaluableforresearchandlong-termplanning,computingresourcechal-lengeslimititsgeneralutilityformakingtimelypredictionsduringactualstormevents.EstablishinganADCIRCcollaborative—aworkingrelation-shipamongresearchcenterswithADCIRCcapabilities—wouldoptimizethedeploymentofthismodelingsystemandenablereal-timeanalysisforthebenefitofcommunitiesaffectedbycoastalstorms.

The Challenge

Manyfactorscombinetomaketheconsequencesofcoastalstormsdifficulttopredict.Theyincludeaconfluenceofmultipleat-mosphericandoceanographicfactors—suchasairandocean

temperature,windspeed,winddirection,tides,stormsurge,andwaveaction—whichtheninteractwithanarrayofbuiltandnaturalstructures.Theimpactofstormsurge,whichisoftenresponsiblefortheextensivefloodingassociatedwiththesestorms,dependsonthesize,intensity,andtrajectoryofthestorm,aswellasthetopographyofthelandandthepresenceofstructuressuchasdunes,levies,orfloodwalls.Similarly,theimpactofwind-generatedwaves,responsibleformuchofthedamagetobuiltstructures,dependsonwindspeedandoceanographicfactors,aswellasthedesignofcoastalcommunities,buildingarchitecture,andotherfactors.Theabilitytoaccuratelypredictfloodingandstructuraldamageiscriticalforplanningroadclosuresandevacuationrouting,shelterandequipmentplacement,andrecoveryandrestorationefforts—allofwhichimpactastorm’shumanandmaterialtoll.

Twomodelsaremostfrequentlyusedforpredictingstormsurgeassociat-edwithcoastalstorms.ThemodeldevelopedbytheNationalOceanicandAtmosphericAdministration(NOAA)istheSea,LakeandOverlandSurgesfromHurricanes(SLOSH)model.SLOSHcanberuninashortenoughtimeintervaltoallowthecompletionofhundredsofmodelrunsbasedon

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differentpredictedstormtrajectoriesandproperties,whichcanthenbeusedtocreatemapsoftheprob-abilityoffloodinginstorm-impactedareas(Taylor&Glahn2008;Glahn,etal.2009).However,twoissueslimitSLOSH’saccuracy.First,SLOSHisnotwrittentoharnessmultiplecomputerCPUssimultaneously,sospatialresolutionmustbekeptrelativelycoarseforsimulationstofitontooneCPUandstillcompletequickly.Second,SLOSHrepresentsspatialfeaturesusinganorthogonalrectangulargrid,whichmakesitimpossibletoachievehighresolutioninthecoastalregionwithoutover-resolvingdeeperwater.Thistypi-callyresultsintheuseofmodeldomainsthataretoosmalltofullycapturethecoastalresponse.

Asecondmodel,ADCIRC,cancomputeextremelyhigh-resolution,detailed,andaccuratepredictions.ItiswrittentouseasmanycomputerCPUsasareavailable,andbecauseADCIRCusestrianglesasitsdescriptivebasis,themodel’sspatialresolutioncanbeveryhighinthecoastalzonewithoutover-resolvingdeeper,offshorewater(Westerink,etal.2008).Usingthisapproach,ADCIRCcangeneratemuchmoredetailedfloodforecastmapsthanSLOSH(seeFigure1).However,whenconfiguredtorunathighspatialresolution,ADCIRCrequiressignificantcomputingre-sources,makingeachrunofthemodelmoreresourceintensivethanSLOSH.

WhileSLOSHandADCIRCgenerallysolvethesameequationsforpredictingstormsurge,ADCIRC

incorporatestwoadditionalmechanismsdirectlyintoitssimulations:astronomicaltidesandbreakingwind-generatedwaves.Astronomicaltides,whicharecausedbythegravitationalattractionsbetweentheearth-moon-sunsystem,causetheperiodicfluctuationsofoceanicwaterlevelseenatthecoast.Themostdan-gerousstormsurgesandwavesarethosethatoccuratthesametimeashightide;however,thetimingofhightideislocation-specific,sothetimeofpeaktideinaninletorsoundmaybequitedifferentfromthetidetimingatanearbybeach.

ADCIRCdynamicallyincorporatesthetideineachmod-elrun,generatingalocation-specifictidalresponseandthereforeamoreaccuratepredictionofstormsurgeresponse.Inaddition,ADCIRCaccountsfortheimpactofwind-generatedwavesonstormsurge.Aswind-generatedwavesbreak,theycantransfermomentumtothestormsurge,increasingthewaterlevelofthestormsurgebyasmuchas5to15percentonwide,shallowcontinentalshelves(Dean&Dalrymple1991;Niedoroda,etal.2008)andsubstantiallymoreonnar-row,steepshelves(Resio&Westerink2008).ADCIRCiscoupledtotheSWANwind-wavemodelandthereforedirectlymodelsthewind-wavefieldandincorporatesthemomentumtransferfromthewavestothestormsurge.Accountingforastronomicaltidesandbreakingwind-generatedwavesimprovesADCIRC’saccuracy;however,italsoaddstothecomputingresourcesre-quiredtorunthemodel.

Figure 1:ADCIRC(graytriangles)andSLOSH(blacksquares)modelgridsintheWrightsvilleBeach,NCarea.BecauseADCIRCusestrianglesasitsdescriptivebasis,itallowsfloodpredictionatamuchgreaterlevelofdetailthanthecoarserSLOSHmodel,whichusessquares.TheredlineisthecoastlineinADCIRC’sgrid.

Theabilitytocomputeasiz-ableensembleofhigh-resolu-tionADCIRCrunswouldpro-videinformationonpredictionuncertaintyand,givenenoughruns(e.g.,100ormore),couldallowthecreationofextremelydetailedprobabilisticfloodandwave-impactpredictionstoguidedecisionmakingdur-ingcoastalstorms.However,severalkeychallengeslimittheutilityofADCIRCforreal-timeensemblesimulations:

1. Horsepower:Dependingonthesizeoftheareabeingmodeled,atypicalfive-daylongforecastruncantakeanhourormoreonseveralhundredtosev-eralthousandcomputer

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processors.Runningmultiplesimultaneoussimula-tionsrequiresmorecomputingpowerthancom-putingcentershaveavailableatanyonetime.

2. Cost: Duetoitshighdemandsoncomputingresources,ADCIRCcanimposesubstantialcostsinpersonnelandcomputingtime.

3. Time: Tobeusefulfordecisionmakingduringanactualstorm,predictionsmustbegeneratedinamatterofhoursorless.Few,ifany,computingcentershavetheavailablecapacitytoperformasizableensembleofhigh-resolutionADCIRCrunsinthistimeframe.Inaddition,thenatureoftropicalstormeventsmeanscomputingresourceswouldneedtobeavailableondemandwithashortwarn-ingperiod—asignificantobstacleforheavily-usedcomputingfacilities.

4. Output Translation: Forecasters, emergency

Ideas into Action: An ADCIRC Collaborative

ADCIRCispoisedtotransitionfromavaluableresearch/designmodelintoapowerfultoolforforecastguidanceanddecisionmaking.ADCIRC

alreadycontainsallofthetechnicalelementsneededtogenerateondemandeithersingledeterministicresultsoranensembleofresultsathighresolutionandtranslatethemforreal-world,real-timeforecasting.Butnosinglecomputingcentercaneasilyachievethisgoalalone.Whatisneededisacollaborativepartner-shipamongcomputingcentersequippedwithADCIRC.

TheUniversityofNorthCarolinaatChapelHill,UniversityofTexas,LouisianaStateUniversity,CollegeofStatenIslandattheCityUniversityofNewYork,andNOAA,areallexperiencedwithADCIRCandcomprisealogicalgrouptoformthebasisofsuchapartnership.

ThispartnershipwillpavethewayforADCIRCtobemoreefficientlyandeffectivelydeployed—andforpredictionresultstobedistributedtoforecastus-ers—wheneverastrongcoastalstormposesathreattotheU.S.coast.TheestablishmentoftheADCIRC

ADCIRCwasdevelopedintheearly1990sbyRickLuettichoftheUniversityofNorthCarolinaatChapelHillandJoannesWesterinkoftheUniversityofNotreDame(Luettich,etal.1992;Westerink,etal.2008).Whiletheyhavecontinuedtoleadmodeldevelopment(e.g.,Dietrich,etal.2011;Tanaka,etal.2011),inrecentyearsthebroaderADCIRCcommunity,comprisedoffederalgovern-ment,academic,andindustryusersandresearchers,hascontributedtoADCIRC’scontinueddevelopmentandim-provement,aswell.TheRenaissanceComputingInstitute(RENCI)helpstomaintaintheADCIRCcodeandservesasthemainADCIRCcoderepository.

Toaccuratelypredictstormsurgeathighresolution,ADCIRCincorporatesavarietyoffactorsaffectingthephysi-calforcesbehindstormsurge(forcingmechanisms),whichareaswillbeinundated(space),andwhenthegreatestimpactswilloccur(time).Thesefactorsinclude:

Forcing mechanisms

• Surfacewindandpressurefrommeteorological

modelsorhurricaneforecasttracks

• Wavebreakingforces

• Astronomicaltides

• Riverdischarge

Space

• Lineartriangularfiniteelements

• High-resolutiontopographyandbathymetry

• Hydraulicstructuresandraisedfeatures(levees,road-ways,channels)

• Locallandroughnessandtreecanopy

• ParallelimplementationviaMPI,DomainDecomposition(METIS)

Time

• Finitedifference,Courant–Friedrichs–Lewytime-steplimited

• User-specifiedmodeloutputrate;hourlysnapshotsofwaterlevelandwavesaretypical

ADCIRC Key Features

managersandotherkeydecisionmakersneedpre-dictivedatainformatsthatfitintodecisionmak-ingtoolsthatarealreadyinplace.Thus,ADCIRCoutputdataneedstobetranslatedintoformsthatarepracticalforuseontheground.

Federalcomputingfacilities(suchastheDepartmentofDefense’sCraysystemsinVicksburg,MS,andNOAA’sJetsystemsinBoulder,CO)havetheneces-saryhardwaretorapidlycreateADCIRCensemblepredictions,buttheseclustersandsupercomputersareheavilyusedandon-demandaccessisgenerallylimited.Atthefederallevel,therehashistoricallybeenmuchmoreemphasisplacedoncomputersimula-tionsofthemeteorologicalcomponentsofahurricaneitself,withlessemphasisoncomputingtheimpactsoftheseeventsintermsofstormsurge,waves,andevendamage.

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collaborativeisenvisionedintwophases.

Phase 1Phase1wouldconnectADCIRCoutputsfromallre-gionalcenterstocreateaunifiedviewofdatafromallADCIRCruns.Toachievethis,allsiteswouldcontributedatatoashareddatamanagementsystemusingstan-darddataformats,metadatadescriptions,anddataaccessprotocols.OneapproachwouldbetomanagethedatausingiRODS(integratedRules-OrientedDataSystem,anadvanceddatamanagementmiddleware,http://irods.org),anduseOPeNDAP(www.opendap.org)andUnidata’sTHREDDS(www.unidata.ucar.edu/projects/THREDDS)fordatacatalogingandaccess.

Ultimately,thesharedsystemwouldtranslatetheoutputdataintoWeb-basedvisualizationsandshape-filesforusebyforecastersandemergencymanagers.ConnectingandstandardizingtheoutputsfromallsitesrunningADCIRCwouldallowcriticalinformationtobeaccessedthroughasinglepoint-of-entry,regardlessofwhichcentergeneratedtheoutputdataorwhichareaswereimpactedbythestorm.

Phase 2InPhase1,onlyADCIRCoutputswouldbedealtwithcollectively.Phase2wouldallowADCIRCsitestogatherinputsandrunthemodelcollectively,thusenablingthecollaborativetorealizetheultimategoalofproducingensemblecalculationsathighresolutionondemand.Poolingthecomputingresourcesofmul-tiplesitesinthiswaywouldnotonlyallowthetimelygenerationofmoresimulationsofastorm-threatened

formalpolicyisneededthroughwhicheachADCIRCsitewouldpre-designatecompu-tationalpowerforon-demandusewhenastormthreatensthecoast,andthatwouldallowremoteADCIRCsystemstousesharedresources.Thisisasignificanthurdlegivenhighdemandsplacedonuniversitycomputeranddatacentersandcompetitionwithothertime-sensitivecomputationalneeds.

Figure 2: ConceptualdiagramofPhase1oftheADCIRCCollaborative.ExistingADCIRCsystemsareshowninblueandcoverthecoastalregionscoveredbytheovals.Plannedsystemsareshowninorange.Eachsys-tempublishesADCIRCmodelresultstoaTHREDDSserver.Currently,onlytheRENCITHREDDSserverisoperating.TheparticipatinggroupsaretheUniversityofTexasatAustin,LouisianaStateUniversity,RENCI,NOAA’sCoastSurveyDevelopmentLaboratory,andtheCollegeofStatenIslandattheCityUniversityofNewYork.ThecollectionofADCIRCresultsisrepresentedbythecloudandismaintainedbytheiRODS(integratedRule-OrientedDataSystem)datamanagementmiddleware.

ADCIRC already contains all of the technical elements needed to generate on demand either single, deterministic results or an ensemble of results at high resolution and translate them for real-world, real-time forecasting. But no single computing center can easily achieve this goal.

area,itwouldalsoprovideanimportantstructureforhandlingtwounlikely(butnotimpossible)scenarios:thattwoormorecoastalstormswouldthreatendif-ferentpartsofthecoastatthesametime,orthatanADCIRCsitewouldgoofflineduringastorm.

Attheconclusionofthisphase,allparticipatingADCIRCsystemswouldbeabletorespondtoanimpendingstormthreatanywherealongthecoastbyconductingmultiplesimultane-ousmodelruns.Theoutputsfromthesemodelrunswouldthenbeintegratedintohigh-resolutionprobabilisticpredictionsandtranslatedintousableformatstoinformdeci-sionmaking.

AchievingPhase2willrequireresearchontwofronts.First,researchisneededtodeterminethebestapproachforthesharedsystemtorequestremoteresources,stagetheneededmodelinputdatatotheremotesite,submittheparallelcomputation,andretrievethemodeloutput.Thisresearchisal-readyunderwayatRENCI,inprojectssuchasExoGENI(www.exogeni.net)andapplicationsoftheiRODSsoftwaretechnology.Second,a

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What Will It Take?

AnADCIRCcollaborativewouldaddressmanyofthechallengesthathavelimitedthereal-worldapplicationofthispowerfulsoftwarethusfar:

1. Horsepower:ThecollaborativewouldgreatlyincreasethecomputationalresourcesavailableforrunningADCIRCduringanactualstormevent.Bydrawinguponthecomputingcapacityofmultiplecomputingcenterssimultaneously,thecollabora-tivewouldallowcoordinated,redundant,parallelmodelruns,increasingthelikelihoodofgeneratingusefulresultsintherequiredtimewindow.Italsowouldallowmodelingofperturbationstoaccountfordifferentpathsthestormcouldtake,ultimatelyenablingthecreationofensemble-basedfloodingpredictions.Finally,itwouldensureADCIRCcouldcontinuetoruninmultiplestatesevenifonecen-terdropsofflineduetostormimpacts.

2. Cost:Acollaborativestructureallowsallcenterstoreapbenefitsfromsharedinfrastructureinvest-ments,reducingtheoverallcosttoeachcenter.Forexample,thesharedoutputsystemdeveloped

inPhase1wouldeliminatetheneedforeachcen-tertodevelopitsownmethodoftranslatingdataoutputsforusebyon-the-grounddecisionmakers,reducingredundancyandthusloweringcosts.

3. Time: ThecollaborativewouldallowmultiplesitestorunADCIRCsimultaneously,thusgeneratingusefulresultsmuchmorequicklythanwouldbefeasibleatanysinglesite.Inaddition,theagree-mentsputinplaceinPhase2wouldensurecom-putingresourcescanbeimmediatelyredirectedforADCIRCwhenastormposesathreat,allowingmodeloutputstobegeneratedintimetomakeadifference.

4. Output Translation: Ratherthanrequiringdatauserstoworkdirectlywithdataproducers,thecollaborativeoutputsystemsdevelopedinPhase1wouldhelpdatacontributorsofferpracticableinformationforuserswithoutneedingtocreatetheinterfacesthemselves.Thiswouldresultinaunified,streamlinedproductavailabletoforecast-ersandemergencymanagers.

TofullyunleashADCIRC’spotential,anewcol-laborativestructureisproposedthatchannelsthecollectiveresourcesofallADCIRC-equipped

centerswhenastrongstormthreatensthecoast.Suchastructurewouldlargelyovercomecurrentcomput-ingresourcelimitationsandultimatelyallowtheproductionofensemblecalculationsathighresolutionondemand.Theextremelydetailed,accuratestormimpactpredictionsgeneratedthroughthiseffortwoulddirectlybenefitemergencymanagersandthepublic—savinglivesandmoney.

ImplementationofPhaseIwillrequiretwocriticalcomponentsandcyberinfrastructureexperts.First,acapablewebprogrammermustbuildafront-endportaltodisplaythedesiredinformationcomingfromtheparticipatingADCIRCcenters.Thiswouldincludea“systemstatus”portalthatgathersreal-timeinforma-tionfromparticipatingcentersusinganAMQPimple-mentationlikeRabbitMQtotrackthestatusofsimula-tions(forexample,pending,running,complete,failed),

collectensemblememberinformation,andlinktotheoutputfilesondataservers.

Second,atechnicianwithknowledgeofthemethodsusedwithADCIRCmusthelpmaintaintheautomatedsoftwareonparticipatingcomputingresourcesandsolveunanticipatedissuesthatariseinfederatingmul-tipleADCIRCinstancesthroughthecollaborativedatagridusingiRODS.

PhaseIIwillrequiremaintenanceofPhaseIactivitiesandtheexpansionoftheweb-basedresultstoincludeeffectivedisplayofensembleresultsandprobabilisticassessments,andtoorganizeandimplementacoordi-natedsetofmodelrunsacrossdistributedresources.TheresourcesharingaspectsofPhaseIIwillrequirepolicyagreementsbetweenparticipatingcentersandadministratorstoenablecross-centercommunicationandcooperation,aswellasadoptionofcomputere-sourcequeuesthatallowpreemptiveandon-demandsimulationsduringstormevents.

This partnership will pave the way for ADCRIC to be more efficiently and effectively deployed—and for prediction results to be distributed to forecast users—whenever a strong coastal storm poses a threat to the U.S. coast.

The Upshot

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How to reference this paper:

Blanton,B.,Luettich,R.,Losego,J.,Fleming,J.&Johnson,A.F.(2013):BuildingtheADCIRCCollaborative.RENCI,UniversityofNorthCarolinaatChapelHill.Text.http://dx.doi.org/10.7921/G0RN35SG