AMPSCONTRIBUTIONSTOTHEYEAROFPOLARPREDICTION–SOUTHERNHEMISPHERE(YOPP–SH)

JordanG.Powers1 andDavidH.Bromwich2

13th WorkshoponAntarcticMeteorologyandClimateUniversityofWisconsin–MadisonMadison,Wisconsin,USA16–18 July2018

1MesoscaleandMicroscaleMeteorologyLaboratoryNationalCenterforAtmosphericResearchBoulder,Colorado,USA

2DepartmentofGeographyandByrdPolarandClimateResearchCenterTheOhioStateUniversityColumbus,Ohio,USA

BACKGROUND

•WMOPolarPredictionProject(PPP)

– Goal:Promoteinternationalresearchtowardimprovedweatherandenvironmentalpredictionforthepolarregions

– Period:2013–2022

•PPPActivity:YearofPolarPrediction

– Period:2017–2019

– Elements:Intensiveobserving,modeling,verification,andeducationalactivities

BACKGROUND

•YearofPolarPrediction–SouthernHemisphere(YOPP-SH)– Focus:Observationandpredictioninthehighsouthernlatitudes

– SpecialObservingPeriod(SOP):November2018–February2019

SOPObservations

ü ExtraradiosondelaunchesEx:4/dayfromNeumayer andDumontD’Urville

ü DeploymentofenhancedsurfaceAWSplatforms

ü Additional SouthernOceandriftingbuoys

ü OceanicobservationsfromshipsEx:Sondes,CTD(conductivity/temp/depth)measurements

AMPS-RELATEDACTIVITIESINYOPP-SH

1)RegularAMPSForecasts

2)Thwaites GlacierStudySupport

3)YOPP-SHDataImpactStudy

– WRFoutputarchivedandweb-accessibleforYOPP-SHstudies

EarthSystemGrid/ClimateDataGatewayatNCAR

https://www.earthsystemgrid.org/project/amps.html

AMPSACTIVITIESINYOPP-SH

1) RegularAMPSForecasts– Models:WeatherResearchandForecasting(WRF)Model

andModelforPredictionAcrossScales(MPAS)

– WRF:5domains— 24km/8km/2.67km/.89kmgridspacings

2)SupportforThwaites GlacierStudy

– InvestigationoftheunstableThwaites Gl:NERC(UK)&NSF(US)sponsors

– Fieldcampaigns(2018–2021):Measureoceanandcurrents,glacierdynamics,andmarinesediments

https://thwaitesglacier.org/

AMPS:Additional,higher-resWRFforecastgridforfield

periodsEx:Dx£ 2.67-km

Thwaites activityyr.1

3)YOPP-SHSOPDataImpactStudyUsingtheAMPSFramework

– Collaboration:TheOhioStateUniversityBPCRCandPolarMeteorologyGroupandNCAR

– Support:NSF

– Components

(i)SOPobs acquisitionandpreparation

(ii)Configurationofmodel,forecasts,anddataassimilationsystem

(iii)Modelsimulations

(iv)Experimentanalyses

YOPP-SHSOPDATAIMPACTSTUDY

•Goal1:Determineeffectsonmodelforecastsofenhancedsouthernhemisphereobservations

– DotheSOPobs improveforecasts?Towhatdegree?

– Overwhattimescalesaretheeffectsseen:Oversubseasonalperiodsorinspecificweatherevents?

® DeterminevalueinmaintainingadditionalSouthern Hemispherehigh-latitudeobs

•Goal2:ExplorevariationsindataassimilationforWRFinAMPSforforecastimprovement

– CandifferentdataassimilationapproachesforWRFyieldAMPSforecastimprovements?

® AdvancethePPPgoalofimprovingpolarNWP

YOPP-SHSOPDATAIMPACTSTUDY

•Background:CurrentAMPSSetup

– AMPSEnsembleWRFForecasts

○ 15-memberWRFensemble(24-km/8-kmgridsonly)

(i)ProvidesensembleguidanceforUSAPforecasters

(ii)GeneratesbackgrounderrorinformationforthedataassimilationforthemainWRFforecasts

○ Memberbackgrounds:NCEPGlobalEnsembleForecastSystem(GEFS)

– AMPSMainWRFForecasts:BackgroundsfromNCEP GFS (GlobalForecastSystem)analyses

Note:YOPP-SHexperiments— CycledWRFforecastsforbackgrounds

YOPP-SHSOPDATAIMPACTSTUDY

•Approach:WRFAntarcticforecasts(i)assimilatingdifferentdataand(ii)applyingdifferentDAprocedures

•ExperimentVariations

1)ObservationsIngested(a)STD obs (standardAMPSoperational)

STDobs:AWS,SYNOP,METAR,shipsandbuoys,radiosondes,aircraftobs,satellitewinds,GPSradiooccultations,

satelliteradiances(b)STDobs +SOPobs

2)DataAssimilation(DA)ProceduresUsed– Variationofthebackgrounderror(BE)covariance

inputstothedataassimilationpackage

DAProcedureExperiments

•CurrentDAforWRFinAMPS:HybridEnsemble/3-DimensionalVariational DA(3DEnVar)

– 3DVARw/backgrounderrorcovariances (BEs)fromtwomethods

(i)BEsfromAMPSmainfcstsusingNMCmethod:StaticBEs

(ii)BEsfromAMPSensemblefcsts:EnsembleBEs (flow-dependent)

AMPSWRFforecastpath

(GFS)

DAProcedureExperiments

•Experiments:WRFDAVariationsUsingNewEnsembles

– Purpose: Generatetwoversionsofflow-dependentBEsforuseintheDA

– Create2new,largerensemblesforexpts: ~60memberseach

ü BEcovariances betterestimatedfromlargerensembles

– Ensembledifferences:Member(a)backgroundsand(b)initializations

○ Ensemble1:GEFSbackgrounds + noDA

○ Ensemble2:CycledWRFbackgrounds+DA

DAmethodused:EnKF (EnsembleKalman Filter)DAforinitializationofmembersusing DART— DataAssimilationResearchTestbed

DAProcedureExperiments

•DABEVariation1

– WRFensemblemembersinitializedfromGEFS

– EnsemblefcstsusedtogenerateBEsfortheDAfortheexperimentfcsts

MainWRFForecasts

WRFEnsembleforBEGeneration

6-hrWRFforecastfornewbackground

Fullfcst forverification

DAProcedureExperiments

•DABEVariation2– CycledWRFensembleusedtogenerateBEsfortheDAfortheexperimentforecasts

DARTusesanEnKF approachforDAininitializingcycledWRFensemblemembersWRFEnsembleforBEGeneration

MainWRFForecasts

– DataAssimilationResearchTestbed(DART) usedforDAfortheensemblemembers

6-hrWRFfcst fornewbackground

X6-hrfcsts formemberbackgrounds

WRFfcst forverification

(WRF)

(WRF)

SOPDATAWRFFORECASTEXPERIMENTS:2TYPES

•PeriodForecasts

– 2-weekperiodsNovember2018 (spring)EarlyJanuary2019 (mid-summer)February2019 (latesummer)

– 24-km/8-kmforecastgridsused

– 2forecasts/day:≥72 hrs

•EventForecasts

– SelectedcasesofsignificantweatheraffectingPalmerandMcMurdo

– Higher-resolutiongridsused:£2.67-km

SECONDARYDATAIMPACTTARGET:GLOBALSOUTHERNOCEAN(GSO)ARRAYDATA

Resourcespermitting:Assessfcst impactofobs fromtheNSFOceanObservatoriesInitiative(OOI)GSOarray

– GSO:55°S90°W

– OOI:Programtomeasurephysical,chemical,geological,andbiologicalpropertiesandprocesses

– DataclaimedtoimproveanECMWFmodelforecast

Aim:LeveragetheYOPP-SHstudytoassesstheinfluenceofthedatafromthisNSFasset

GSOArray

OOIResearchArrays

SUMMARY

•AMPSContributionstoYOPP-SH

(1)ContinuedAMPSforecastsanddataarchiving

(2)Thwaites Gl.studysupport

(3)SOPdataimpactstudy

•YOPP-SHDataImpactStudy

– ExamineeffectsofSOPdataonWRFAntarcticforecasts

– VariationofdataassimilationapproachesinAMPS

– Goals

•DetermineforecastvalueofextraSouthernHemisphereobs

•IdentifyimprovementsforDAin AMPS