TheYearofPolarPrediction

WhitePapersubmittedtotheArcticObservingSummit2016Authors:HelgeGoessling*,ThomasJung,StefanieKlebe,NeilGordon,PeterBauer,AliceBradley, David Bromwich, Barbara Casati, Peter Chen, Matthieu Chevallier, JonathanDay, Francisco Doblas-Reyes, Christopher Fairall, Øystein Godøy, Marika Holland, JunInoue, Trond Iversen, Daniela Liggett, Gita Ljubicic, François Massonnet, AlexanderMakshtas,BrianMills,PerttiNurmi,DonaldPerovich,PhillipReid,IanRenfrew,GregorySmith,EmmaStewart,GunillaSvensson,MikhailTolstykh,andQinghuaYang*CorrespondingAuthor:HelgeGoessling,AlfredWegenerInsitute,HelmholtzCentreforPolarandMarineResearch,Bremerhaven,Germany,helge.goessling@awi.deExecutiveSummary:TheYearofPolarPrediction(YOPP)hasthemissiontoenableasignificantimprovementin environmental prediction capabilities for the polar regions and beyond, bycoordinating a period of intensive observing,modelling, prediction, verification, user-engagement and education activities. The YOPP Core Phasewill be frommid-2017 tomid-2019, flanked by a Preparation Phase and a Consolidation Phase. YOPP is a keycomponent of the World Meteorological Organization – World Weather ResearchProgramme(WMO-WWRP)PolarPredictionProject(PPP).TheobjectivesofYOPPareto:

1. Improve the existing polar observing system (better coverage, higher-qualityobservations);

2. Gather additional observations through field programmes aimed at improvingunderstandingofkeypolarprocesses;

3. Develop improved representation of key polar processes in coupled (anduncoupled)modelsusedforprediction;

4. Developimproved(coupled)dataassimilationsystemsaccountingforchallengesinthepolarregionssuchassparsenessofobservationaldata;

5. Explore the predictability of the atmosphere-cryosphere-ocean system, with afocusonseaice,ontimescalesfromdaystoseasons;

6. Improve understanding of linkages between polar regions and lower latitudesandassessskillofmodelsrepresentingtheselinkages;

7. Improve verification of polarweather and environmental predictions to obtainbetterquantitativeknowledgeonmodelperformance,andontheskill,especiallyforuser-relevantparameters;

8. Demonstratethebenefitsofusingpredictiveinformationforaspectrumofusertypesandservices;

9. Provide training opportunities to generate a sound knowledge base (and itstransferacrossgenerations)onpolarpredictionrelatedissues.

ThePPPSteeringGroupprovidesendorsement forprojectsthatcontributetoYOPPtoenhance coordination, visibility, communication, and networking. ThisWhite Paper isbased largely on the much more comprehensive YOPP Implementation Plan(WWRP/PPPNo.3–2014),buthasanemphasisonArcticobservations.

1. IntroductionThere has been growing interest in the polar regions in recent years due to theopportunities and risks associated with anthropogenic climate change. Increasingeconomic,tourism,transportation,andscientificactivitiesinpolarregionsareleadingtomoredemandsforenhancedenvironmentalpredictioncapabilitiestosupportdecision-making.Furthermore,thereisincreasingevidencethatweatherandclimateinthepolarregions have a substantial influence on the lower latitudes. However, forecastingcapabilities inthepolarregionsare laggingbehindcomparedtomid-and low-latitudepredictions. The probably most important reason for this is the sparseness of polarobservations (Figure 1), posing challenges to data assimilation, forecast initialization,processunderstanding,modeldevelopment,andforecastverification.

Figure 1: Conventional observations that were assimilated by the operationalforecastingsystematECMWFon15April2015.Differentcolorsareused fordifferentobservationtypes(seelegend).ThestrinkingobservationalgapintheArcticexistsalsoforotherimportantdatatypes,inparticularArgofloatsintheocean.FigurefromJungetal.(2016).

Recognizing this, theWorldMeteorological Organization –WorldWeather ReasearchProgram (WMO-WWRP) has decided to embark on a decade-long Polar PredictionProject from 2013 to 2022. The key element of PPP is the Year of Polar Prediction(YOPP)withaCorePhasetakingplacebetweenmid-2017andmid-2019.

TheYOPPMissionisto:Enableasignificantimprovementinenvironmentalpredictioncapabilitiesforthepolarregionsandbeyond,bycoordinatingaperiodofintensiveobserving,modelling,prediction,

verification,user-engagementandeducationactivities.Inotherwords,YOPPisanextendedperiodofcoordinatedintensiveobservationalandmodelling activities, aimed at improving prediction capabilities for the Arctic, the

Antarctic, and beyond. This concerted effort will be augmented by research intoforecast-stakeholder interaction, verification, and a strong educational component.BeingpartofthePolarPredictionProject,YOPPconcentratesontimescalesfromhoursto seasons.With its clear focusonpolarprediction rather than a verybroad rangeofpolarsciencetopics,YOPPisquitedifferentfromIPY(theInternationalPolarYear2007-2008).Predictionofkeyvariablessuchasvisibility,wind,precipitation,andinparticularsea ice, is central to YOPP. The presence of linkages between polar and non-polarregionssuggeststhatthebenefitofYOPPwillextendbeyondthepolarregions.Extraobservationswillbecrucial toYOPPinorderto(i)optimizethepolarobservingsystem, (ii) generate the knowledge necessary to improve the representation of keypolarprocesses inmodels, and (iii) provideground-truthing that it is so important toexploit the full potential of the space-borne satellite network. YOPP will provide anopportunity for testing new observational activities, and will encourage research,developmentandemploymentofinnovativesystems.Another important aspect of YOPP will be a strong virtual component throughinvolvement of the numerical modelling community, encompassing models of theatmosphere,ocean,seaice,andland.Operationalmodelrunswillcovertimescalesfromhours to seasons. A particular focus will be on sea ice, since for polar regions thismedium is both a critically important environmental variable to be predicted, and astrongmodulatorofotherweather-relatedpredictands(Figure2).

Figure2:Mean2-mtemperaturedifference(inK)betweenhindcastexperimentsusingobservedandpersistedseaiceandseasurfacetemperatureat5daysleadtimewiththeECMWF forecasting system for October 2011. The large errors along the ice edgehighlight the importance of coupled processes even for near-term prediction in polarregions.FigurefromJungetal.(2016).

Strivingtoimprovepolarpredictions,theadditionalobservationscollectedduringYOPPwill beutilized in severalways.Theobservationswill beused (i) indata assimilationsystems to improve forecast initialization, assess the relative merits of differentobservation types, locations, and frequencies (by means of observing system(simulation) experiments, i.e., data denial experiments), and further develop coupleddata assimilation techniques, (ii) as basis for forecast verification, and (iii) to studyprocessesthatarekeytoimprovedpolarpredictions,forexampleprocessesrelatedto

the stable boundary layer, sea ice, mixed-phase clouds, and polar lows. YOPP-relateddata from observations andmodels will be shared using standardised interfaces anddocumentationstandards,alsoenablinglong-termdatapreservation.AdedicatedYOPPData Portal will provide a unified framework of the data hosted by the data centrescontributingtoYOPP.YOPP will also explore largely uncharted territory in the area of polar forecastverification;YOPPwillcontributetoourunderstandingof thevalueof improvedpolarpredictioncapabilities;andYOPPwillhelptoeducatethenextgenerationofscientists.YOPPwillbecarriedoutinthreephases:aPreparationPhasefrom2013tomid-2017,aCorePhase frommid-2017 tomid-2019,andaConsolidationPhase frommid-2019 to2022(Figure1).EachofthesephasesisdiscussedinthefollowingSections.In order to achieve the research objectives listed in the executive summary, strategicaspectsofYOPPareto:

A. Strengthen linkages between academia, research institutions and operationalforecastingcentres;

B. Establish and exploit special research data sets that can be used by thewiderresearchcommunityandforecastproductusers;

C. Establish a common virtual data archive through integration of contributingarchives;

D. Linkwithspaceagencies;E. PromoteYOPPwithfundingagencies;F. Developstronglinkageswithotherinitiatives;G. Promoteinteractionsandcommunicationbetweenresearchandstakeholders;H. Fostereducationandoutreach.

Figure3:ThephasesofYOPPandkeyactivitiestherein

Prepara&onPhase2013tomid-2017

Consolida&onPhasemid-2019to2022

Communityengagement

Fundraising&Resourcemobiliza&on

Alignmentwithotherplannedac&vi&es

Preparatoryresearch

SummerschoolWorkshops

DevelopmentofImplementa&onPlan

Intensiveobservingperiods&satellitesnapshot

Dedicatedmodelexperiments

Researchintouse&valueofforecasts

Intensiveverifica&oneffort

Modeldevelopments

Dedicatedreanalyses

Opera&onalimplementa&on

Datadenialexperiments

Prepara&onPhase2013tomid-2017

CorePhasemid-2017tomid-2019

Consolida&onPhase

mid-2019to2022

Evalua&onofforecastimprovementsanduse

SummerschoolWorkshops

Coupleddataassimila&on

YOPPpublica&ons

YOPPconference

2. YOPPPreparationPhase(2013tomid-2017)ThecurrentPreparationPhaseiscrucialforthesuccessofYOPP.Itinvolvesanumberofaspects–overallplanning,engagementwithstakeholders,coordinationofobservationsandrelatedfieldprogrammes,promotionofmodellingactivities,establishmentofdataarchivesystems,preparatoryresearch,andinvolvementoffundingagencies.YOPPwasdevisedfollowingthefirstmeetingofthePPPSteeringGroupinSwitzerlandinDecember2011.TheinitialconceptforYOPPisoutlinedinthePPPImplementationPlan(WWRP/PPPNo.2–2013).TheInternationalCoordinationOffice(ICO) forPolarPrediction,hostedat theAlfredWegener Institute inGermanyandresponsible for theoverallmanagementofPPP,isalsoinchargeoftheoverallmanagementofYOPP.YOPPPlanningMeetings involvingmembersof theWWRP-PPPSteeringGroupaswellas participants representing important partners (Table 1)were held 2013 in the UK,2014 in Finland and Canada, and 2015 in Switzerland. The last of these – the YOPPSummit - was special in that about 120 scientists, stakeholders, and representativesfrom operational forecasting centers, international bodies, and funding agencieswereassembledtomakemajorprogressintheplanningoftheapproachingYOPPCorePhase.TheoutcomesofextensivediscussionsheldattheYOPPSummitarethebasisforafinalrevisionof theYOPPImplementationPlanwhichwillbepublishedaheadof theArcticObservingSummit2016.Table1:SelectedYOPPPartners(coordinatingbodies;acronymsareexplainedinthe

appendixoftheYOPPImplementationPlan).

Group Role

APECS ImplementationofeducationalcomponentofYOPP

CBS/IntegratedObservingSystems

Facilitatingtheimprovementofpolarobservingsystems

EC-PHORS Overallpolicyperspective

EUCOS Additionalobservationsovernorthernpolarregions

GASS Coordinationofpolarmodelintercomparisonprojects

GCW Cryosphericobservations,andpotentialuseoftheGCWportal

GODAEOceanview Development and implementation of the intensive modellingcampaign(ice-ocean)

IASC PlanningofYOPPfornorthernpolarregions

IASOA Contributing observations and research based on pan-Arcticatmosphericobservatories

IICWG Coordinationofoperationaliceservices

MOSAiC Gatheringdata fromandaround thedriftingobservatory to improvecoupled models and coupled data assimilation, and for ground

truthingofsatellitedata

PCPI Closecoordinationofrelatedactivities

PSTG Supportingtheexploitationofsatellitedata(“satellitesnapshot”)

S2S Sub-seasonaltoseasonalaspectsofpolarpredictions

SAON CoordinationofArcticObservations

SCAR PlanningofYOPPforsouthernpolarregions

SeaIcePredictionNetwork CollaborationonArcticsea-iceprediction

SOOS CoordinationofSouthernOceanObservations

WCRP/CliC ClosecoordinationofrelatedactivitiesofCliCanditsworkinggroups

WGNE Development and implementation of the intensive modellingcampaign(atmosphere)

WGSIP Encouraging institutions with prediction capability to use initialconditionsthattakeadvantageofthenewavailabledatafromYOPPtorerunsomesub-seasonalandseasonalpredictions

The identification of, and engagement with, key partners for YOPP is an importantelement of the Preparation Phase (Table 1). Another crucial element at a slightlydifferent level is the excitationof, support for, and coordinationof individualprojectsandinitiativesthatfillYOPPwithlife.Inthepast,anumberofscientistsseekingfundsfromdifferentfundingagenciesforprojectspotentiallycontributingtoYOPPhavebeensupported with individual letters of support. At the YOPP Summit it was decided toestablishanendorsementprocessthatfulfilsthesetasksinamoresystematicmanner.For projects and initiatives to be endorsed, criteria include, among others, thecontribution to the general YOPP objectives, willingness for close coordination withotherYOPPactivities,andopendatasharing.Requestsforendorsementarereviewedbythe PPP Steering Group. During the first four weeks, more than 10 projects andinitiatives have requested YOPP endorsement. Among the earliest endorsed are forexample:aprojectcontributingadditionalupperairsoundingsfromNeumayerStation(Antarctica) and RV Polarstern; the Forum for Arctic Modelling and ObservationalSynthesis (FAMOS); a project conducting an Arctic Earth Observation ImpactAssessment; and the Group on Earth Observations Cold Regions Initiative (GEO-CRI).Details on the endorsement process and an up-to-date list of endorsed projects andinitiativesisgivenat<http://www.polarprediction.net/yopp/yopp-endorsement.html>.Anumberof important scienceworkshopshas alreadybeen co-organizedbyPPP, forexampleaPolarPredictionWorkshopheld intheUK(2013),aPPPScienceWorkshopheldintheUS(2013),aPolar-LowerLatitudeLinkagesWorkshopheldinSpain(2014),a SERA Workshop held in Canada (2015), and a Workshop on the Dynamics ofAtmosphere-Ice-OceanInteractionsintheHigh-LatitudesheldinNorway(2015).Another important outcome of the YOPP Summitwas the establishment of additionalsub-committeesthattaketheleadinfosteringcertainaspectsofYOPP.Theexistingsub-

committees on (i) Sea-Ice Prediction, (ii) Societal and Environmental Research andApplications (SERA), and (iii) Education are complemented with committees on (iv)SouthernHemisphereaspects,(v)CoordinatedModelExperiments,(vi) theYOPPDataComponent, and (vii) Arctic Observations and Intensive Observing Periods. Most ofthesearenowintheprocessofbeingestablished(asofNovember2015).Asubstantialpartof the furtherYOPPplanningwill takeplacewithin thesesub-committeesandonpre-YOPPworkshopstheyareorganizing,focussedontheirrespectivethemes.

3. YOPPCorePhase(mid-2017tomid-2019)ThemainYOPPactivitiesareplannedtotakeplaceduringtheperiodmid-2017tomid-2019 – centred on the year 2018. The YOPP Core Phase encompasses four majorelements: an intensive observing period, a complementary intensive modelling andforecastingperiod,aperiodofenhancedmonitoringofforecastuseindecisionmakingincludingverification, anda special educational effort.Hereweonly sketchaspectsofobservationalactivitiesintheArctic.YOPPwilltakeadvantageoftheexistingoperationaldatagatheredunderWMOauspicesfor the globe, including polar regions. Additional observations promoted during theYOPP Preparation Phase will fall into the following categories: (i) comprehensivereference stations, (ii) field campaigns, (iii) aircraft campaigns, (iv) shipping, (v) freetroposphere, (vi) sea ice and upper ocean, (vii) open ocean, (viii) deeper ocean, (ix)autonomoussensorsystems, (x)snow,(xi) land, (xii)boundary layersandclouds,andalso (xiii) stakeholders. All of these categories are discussed in detail in the YOPPImplementationPlan.It has been realized that maintaining certain types of Polar observations (e.g., fourradiosonde launches daily) over two full years is not feasible. Therefore, extraobservationswill concentrate on IntensiveObserving Periods (IOPs)within the YOPPCorePhase. Taking into account operational feasibility, physical processes, benefit fordataassimilationsystems,andsocio-economicrelevance, thetimingofArctic IOPshastentativelybeendeterminedasfollows.TherewillprobablybetwoArcticIOPs,withonecoveringafullopen-waterseason(JunetoNovember2018)andone focusingonwinter (January toMarch2019).ThestartoftheArcticsummerIOPwellbeforethesea-iceminimumisrequiredtoensurethatlong-termpredictionsfortheeconomicallyrelevantlatesummer/earlyautumnseasoncanbewell initialized.To improvepredictionson shorter time scales (hours todays) for thesametargetperiod,ontheotherhand, itwillbe importanttoenhanceobservations inlatesummerandearlyautumn.Furthermore, itwasstronglyargued forextending theIOP to late autumn to capture the time of year when atmosphere-sea ice-oceaninteractions are most vigorous. The shorter Arctic winter IOP will take place inoperationally more challenging conditions and will be targeting phenomena such asPolarlows,snow,cold-airoutbreaks,andstableboundarylayerprocesses.ItisimportanttonotethatthetemporalfocusonIOPsdoesnotimplythatobservationstaken outside IOPs but within the YOPP Core Phase, or even in the late PreparationPhaseorearlyConsolidationPhase,wouldnotbeuseful forYOPP.Forexample, someobservation types will be more continous in nature (e.g., extra automatic weather

stations and floats), and some relevant observational campaigns will not be able tocomplywithIOPsforpracticalreasons(e.g.,MOSAiC).Given the strong involvement of operational forecasting centers, YOPP will not onlybenefit fromadditionalobservationsperse,butalso fromadditionalefforts toprovideobservational data in (near-)real-time via the WMO Information System / GlobalTelecommunication System (WIS/GTS). The revised YOPP Implementation Plan willinclude a “How-To” chapter to facilitate real-time data provision for the researchcommunity.

4. YOPPConsolidationPhase(mid-2019to2022)TheConsolidationPhasewillbeasimportantastheearlierphasesinthatitwillensuretoprovidealegacyofYOPP.Besidetheholdingofsynthesisworkshopsandconferences,implementationofYOPPfindingsintooperationalforecastingsystems,andevaluationofforecastimprovementsandtheirusebystakeholders,itwillbecrucialtoensureproperarchiving, availability, and traceability (Digital Object Identifiers) of the additionalobservationaldatageneratedduringYOPP.Tothisend,aYOPPDataPortal,buildingonthe experience of theGlobal CryosphereWatch (GCW)Portal,will be implemented toenable an efficient exploitation of YOPP data. GCW data management is based onachievements indistributeddatamanagement systemsduring the InternationalPolarYear and alignment of these achievements with relevant WMO activities like WMOInformation System (WIS) andWMO Integrated Global Observing System (WIGOS) aswellasthecombinedSAON/IASCArcticDataCommitteeandSCARStandingCommitteeon Antarctic Data Management (SCADM). The foundation of this is standardiseddocumentation of datasets using metadata describing whomeasured/modelled/analysedwhat,whereandwhen,aswellastheaccessmechanismsto data and potential constraints. Integration of YOPP data management with WISensurethatYOPPdataareexposedthroughtheGEOSSCommonInfrastructureaswellas for other WMO programmes (e.g., the emerging Polar Regional Climate Centre).WIGOS metadata describes instrumentation, procedures and facilities used to collectobservationaldataandensuresproperunderstandingofquality,comparabilityandhowrepresentativedataare.ItisalsothebasisforWMOprogrammesnetworkdesign.TheadditionaldatacollectedduringYOPPwillbeusedduringtheConsolidationPhaseto evaluate the benefit of extra observations for polar predictions. This includes datadenial experiments which will provide guidance for optimizing the polar observingsystem.Furthermore, the extraobservations alongwith thehigh-resolutionnumericalexperimentswillbenefitmodeldevelopmentandtheenhancementofvalueofsatellitedatainapredictioncontext.InordertosynthesizetheavailableYOPPdataandtoexploittheminmodels,itwillbedesirable to carry out special (high-resolution) reanalyses for the Arctic (as for theAntarctic). This will be an ongoing activity during the Consolidation Phase. Suchreanalysesalongwith theavailabilityof reforecastdata setswillprovide thebasis forprobabilistic forecast calibration and for diagnostic and verification studies that areexpected to advance polar prediction across a wide range of time scales. Finally, inparticularthestronglyinvolvedofobservationalcenterswillenableaseamlesslegacyof

YOPP by utilizing an optimized polar observing network and improved forecastingsystemsforbetterpolarpredictionsbeyond2022.

5. FinalRemarksThisWhitePaperhasbarelytouchedonsomeaspectsthatareimportantingredientsfora successful YOPP, including coordinatedmodel experiments, education and outreachefforts, funding aspects, verification, data assimilation, satellite data, andmore. If youwant to learn more, and want to stay informed, about YOPP, the website of theInternational Coordination Office for Polar Predicion at<http://www.polarprediction.net> hosts all relevant information, including workshopand meeting reports, the PPP and YOPP Implementation Plans, a frequently updatednewssection,andinformationonupcomingevents(includingthepre-YOPPworkshops)and on the endorsement process. Another way to get more information is to follow@polarpredictiononTwitter,and/ortosubscribetothepolarpredictionmailinglistbysendinganemailto<office@polarprediction.net>.TheremainingoneandahalfyearsofthePreparationPhasearecruciallyimportanttomaking YOPP a fruitful endeavor. Ultimately, the success of YOPP depends on theenthusiasmandwillingnessofscientiststocontributewiththeirprojectsandinitiatives.TheArcticObservingSummit2016 isaprimeopportunity to informonYOPP,discussArctic observations needed for YOPP, and to excite corresponding contributions toYOPP.WeinviterequestsforYOPPendorsementnotonlyforalreadyfundedprojectstomaximizecoordinationandmutualbenefits,butalsotosupportplannedprojectsintheireffortstoobtainfunding.Selectedpublications:PPP Steering Group and Coauthors: Implementation Plan for the Year of PolarPrediction,WWRP/PPPNo.3,2014 (newerversionavailableby the timeof theArcticObservingSummit2016)Goessling,H.andCoauthors:PavingtheWayfortheYearofPolarPrediction,Bull.Am.Met.Soc.,2015Jung,T.andCoauthors:Advancingpolarpredictioncapabilitiesondailytoseasonaltimescales,Bull.Am.Met.Soc.,2016Jung, T. and Coauthors: Polar-lower latitude linkages and their role in weather andclimateprediction,Bull.Am.Met.Soc.,2015