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AssimilationofHimawari-8AtmosphericMotionVectorsintotheNumericalWeatherPredictionSystemsofJapanMeteorologicalAgency
Koji YamashitaJapanMeteorologicalAgency
kobo.yamashita@met.kishou.go.jp13thInternationalWindsWorkshop,Monterey,
California,USA,27June- 1July,2016113thInternationalWindsWorkshop
OperationalAMVs(OPE-AMVs)SatelliteStatusupdateforNWPuse inJMA
* K.Yamashta 2016:AssimilationofHimawari-8atmosphericmotionvectorsintoJMA’soperationalglobal,mesoscaleandlocalNWPsystems.CAS/JSCWGNERes.Activ.Atmos.OceanicModel,Submitted.
2
EQ
N60
S60
MTSAT-2 GOES-15(Hourly)
GOES-13(Hourly)
METEOSAT-7
METEOSAT-10
From 6 May 2014
From 10 Aug. 2010
From 6 May 2014
From 5 Feb. 2007
From 18 Feb. 2013
NESDIS and CIMSS MODIS polar winds (Terra and Aqua) from 28 May 2004 AVHRR polar winds from 1 Jul. 2013LEO-GEO winds from 1 Jul. 2013
Same as the North Pole region
Himawari-8
From 17 Mar. 2016*
Himawari-8 AMVs have also assimilated into JMA’s operational regional NWP Systems as same method except Super-observation scheme as the operational global NWP Systems since 17 March 2016.
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TODAY’STALK
AssimilationofHimawari-8AMVsintotheoperationalglobalNWP
SystemofJMA
3
Hereafter the items associated with regional NWP Systems are abbreviated.(The impacts for regional NWP system will be presented by Michiko Otsuka and Kenichi Nonaka in presentations tomorrow.)
Outline
• Background• Purpose• NWPsystemforObservingSystemExperiment(OSE)• CharacteristicsofHimawari-8AMVs• Qualitycontrol• OSEresults• Summaryandfutureplans
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Background
• TheMeteorologicalSatelliteCenterofJMAstartedproductionofHimawari-8AMVsonJuly7th,2015.– TheAMVsarebeingproducedusingthreesequentialHimawari-8imageswith10minutesinterval.
• ItwasreportedthatthequalityoftheHimawari-8AMVshasbeenimprovedbyemployingnewtrackingandnewheightassignmentalgorithms.(PresentedbyKazuki Shimoji inpresentationsyesterday)
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Purpose
• TostartassimilatingHimawari-8AMVsinJMA’soperationalNWPSystemswithmaximizing itsimpact
• Forthispurpose,– ItneedstoreviewthequalityofHimawari-8AMVsbycomparingwithMTSAT-2AMVsindetail.• CharacteristicsofHimawari-8AMV
– Anditneedstorevisethequalitycontrol(QC)suitablefortheHimawari-8AMVs.
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NWPSYSTEMFOROSE
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NWPsystemforOSE
8
Global(GSM-DA)
Purposes Short- andmedium-rangeforecasts
Forecastdomain Globe
Gridsize 20km
Verticallevels/Top 100/0.01hPa
Forecastrange(Initialtime) 84hours(00,06,18UTC)264hours(12UTC)
Initialcondition 4D-VarAnalysisTimewindow 6-hourInner-loopmodelres. 55km
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CHARACTERISTICSOFHIMAWARI-8AMVS
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CharacteristicsofHimawari-8AMV• EvaluatedstatisticallyagainstthefirstguessesoftheGSM-DA
• ComparedwithMTSAT-2AMVs• Conditions
– Over60QualityIndicator(QI)withforecast– Period:From5Februaryto20March2015– Investigationitems
• Histogramsofthenormalizeddifference(O-B)betweentherelevantwindspeedsandfirstguesses
• Results– ProperGaussiandistributionsindataassimilation– BetteraccuracyHimawari-8AMVscomparingtoMTSAT-2AMVs
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O-BnormalizedhistogramsofHimawari-8AMVsintheNorthernHemisphere(polewardof20N)
11
NH-IR-HL NH-IR-ML NH-IR-LL
NH-VS-LLNH-WV-HL
0.15 2.63 -0.77 3.22
1184701398727
H8 sample num.MT2 sample Num.
H8: ME STDMT2:ME STD
1238220254619
-0.08 2.39 -0.76 3.15 2655491
1779867-0.16 1.65 0.03 1.73
1100327502840
-0.09 1.56 0.02 1.60
0.44 2.65 0.31 3.28 1884951
517113
ME: Mean Error (unit m/s)STD: Standard Deviation (unit m/s)
IR(B07+B13)
VIS(B03)
WV(B08+B09+B10)
HL:≦400 hPaML:400~700 hPaLL:≧700 hPa
HL ML LL
O-B normalized histograms for other regions has the same characteristics.
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QUALITYCONTROL(QC)
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QCforHimawari-8AMVs
• TosupporttheeffectiveuseofHimawari-8AMVs,theAMVpre-processingsystemwasupdatedinthreemainways.– Revisedqualityindicator(QI,Holmlund 1998)withforecastthresholds
forlow-qualityAMVrejection– Revisedclimatologicalchecking
• RejectionofIRandVISAMVsoverlandbelow700hPa• UseofAMVsinthemiddle troposphere (utilization limitationrelease)
– Introduceda100-kmsuper-observationtechniqueforJapanandthesurroundingareas intotheglobalNWPsystem (introduceda200-kmthinningschemefortheotherregions)
• DetailsofotherQCmeasuresareprovidedontheNWPSAFAMVmonitoringpage*.*http://nwpsaf.eu/monitoring/amv/amvusage/jmamodel.html
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Super-observation(SPOB)technique• Purpose
– PreventionofobservedinformationlossofmanyAMVsbythinning
– Reductionofbothobservationerrorsandfirstguesserrors– Improvementofmeantyphoonpositionalerrors
• ImprovementoftyphoontrackforecastsbyOSEsforMTSATRS-AMVswithSPOBin2013and2014(Yamashita2014,IWW12)
• Method– AveragingofAMVs(observationtime,level,space,winddirectionsandspeeds)by100kmx100kmx100hPa (definedas100kmSPOB)intervalsineachhourlytimewindowinassimilationforJapanandthesurroundingareas(20Nto45Nand120Eto150E)
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VerificationsofSPOBtechnique• UsingMTSAT-1RRapidScanAMVsfromOct.1toOct.30,
2014• Targetedfora100kmSPOBgridpointaroundCHICHIJIMA• InvestigationitemsØ Histogramofthenormalizeddifference betweenwindspeedsand
CHICHIJIMASonde ObservationsorfirstguessesØ ComparedwithSPOBAMVsandallsensorsAMVs
15
TOKYO
CHICHIJIMA
One SPOB grid point
HL:≦400 hPa LL:≧700 hPaHL:≦400 hPa LL:≧700 hPa
Rel
ativ
e fre
quen
cy
First guess departure (O-B) (m/s)Sonde departure (AMV-SONDE) (m/s)
■SPOB AMVs after QC ■All sensors AMVs after QC
・Improved Gaussian distribution・Almost reduction of AMV-SONDE and O-B wind speed differences
improved improvedimproved
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OSEFORHIMAWARI-8AMV
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ExperimentalDesignforGlobalNWPsystem
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Name Specification(Maindifferences)CNTL Aschemeofthe200kmthinningofOPE-AMVs
inthe6hourtimewindow
TEST CNTL+QCforHimawari-8AMVs(100kmSPOBetc.)(100kmSPOBforJapanandthesurroundingareasand200kmthinningfortheotherregions)+NOMTSAT-2AMVs
• Period– Winter2015
• Assimilation :From17Januaryto11March2015• Forecast:From17Januaryto28February2015
– Summer2015• Assimilation:From 3Julyto11September2015• Forecast:From3Julyto11September2015
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DatacoverageandwindspeedSTDdifferencesbetweenTESTandCNTLonanalyzedfields
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●GOES-15 ●MET-7 ●LEOGEO
00 UTC 20 July 2015
CNTL TEST
O-B wind speed STD differences below 700 hPa for summer 2015
BetterW
orse
Normalized O-B wind speed STD differences against JMA’s wind profiler observations for summer 2015
●MTSAT ●Himawari-8
WorseBetter
• Improved data coverage• Reduction of O-B wind speed differences
over the Himawari-8 observation area( especially around Japan )
• Impact of revision of derived wind vector methods and introduced SPOB around Japan
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ResultsofOSEinsummer2015
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Forecast lead time (hours)
BetterW
orse
Normalized RMSE differences around Japan between TEST and CNTL for 850 hPa wind vectors Average of typhoon positional errors
TESTCNTLBST
Typhoon track forecast of NANGKA (T1511) initialized at 12 UTC on 13 July 2015.
Improved
Enhancement ofwind speed to the northward
Enhancement of jet stream
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U V
Analyzed field of U-component and V-component winds around Japan (Zonal mean meridional cross sections: TEST-CNTL)
Summary(1/2)• CharacteristicsofHimawari-8AMV
– Useofnewtrackingandnewheightassignmentalgorithms– ProperGaussiandistributionsindataassimilation– BetteraccuracyHimawari-8AMVscomparingtoMTSAT-2AMVs
• QCforHimawari-8AMV– RevisedQIwithforecastthresholdsforlow-qualityAMVrejection– Revisedclimatologicalchecking– Introductionofa100-kmsuper-observationtechnique(SPOB)forJapan
andthesurroundingareas
• ResultsofOSEs– Modificationofatmosphericgeneralcirculation(especiallyHimawari-8
observationarea)Ø Enhancementof windspeedtothenorthwardØ Enhancementof jetstream,andshiftofthestreamtothesouthward
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Summary(2/2)• ResultofOSE(continuation)
– ReductionofO-BwindspeeddifferencesovertheHimawari-8observationarea(especiallyaroundJapan)
– Significantimprovements(upto3– 6%onaverage)for850hPawindvectorsuntiltwo-dayforecastsaroundJapanforsummer2015
– Improvementofmeantyphoonpositionalerrors(Thereductionwasaround6%with24-hourto48-hourforecastleadtimes.)
– PositiveimpactsonmostphysicalelementsandheightsintheSouthernHemispherewerealsoseeninfour-dayforecastsforwinter2015(notshown)
– Positiveorneutralimpactsforotherphysicalelementsandheights/regions
• Himawari-8AMVswiththerevisedpre-processingsystemhaveintroducedintheJMA’soperationalNWPsystemssince17March2016.
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Futureplans• IntroductionofminorrevisionofQCforHimawari-8AMVinOctober2016– RejectionofHimawari-8AMVswithnegativewindspeedbiasesassociatedinjetstream
• ProperregionexpansionfromJapanareasofAMVswithSPOBmethodintotheglobalNWPsystem
• UseofHimawari-8AMVswithSPOBmethodintotheregionalNWPsystems– Considerationofsuper-observationprocedureintheappropriateareaandgridsize
• UseofnewpolarAMVsin2017– S-NPP/VIIRS,Dual-Metop/AVHRR,Terra/MISR,Aqua/AIRS
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THANKYOUFORYOURATTENTION
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BACKUP
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NWPsystemforOSE
25
Global(GSM-DA)
Meso-Scale(MSM-DA)
Local(LFM-DA)
Purposes Short- andmedium-rangeforecasts
Very-short-rangeforecasts,aviationforecasts
Forecastdomain GlobeJapananditssurroundingareas
Japananditssurroundingareas
Gridsize 20km 5km 2km
Verticallevels/Top 100/0.01hPa 48/21.8km 58/20.2km
Forecastrange(Initialtime)
84hours(00,06,18UTC)264hours(12UTC)
39hours(00,03,06,09,12,15,18,21UTC)
9hours(hourly)
Initialcondition 4D-VarAnalysis 4D-VarAnalysis 3D-VarAnalysis
Timewindow 6-hour 3-hour3D-Varanalysesand1-hforecastsarerepeatedinturnfor3hours.
Inner-loopmodelres.55km 15km 5km
Today’s talk
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QIthresholds• RevisedinconsiderationofHimawari-8AMVcharacteristics
26
Area Sensor HL(≦400hPa)
ML(400-700hPa)
LL(≧700hPa)
NH(polewards of20N)
IR(B07+B13) 85 94 88
VIS(B03) 88 95 85
WV(B08+B09+B10)
85 85 ―
EQ(20S-20N)
IR 85 85 88
VIS 95 90 85
WV 85 85 ―
SH(polewards of20S)
IR 92 91 93
VIS 96 96 85
WV 95 85 ―
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Climatologicalchecking
• RejectionofIRandVISAMVsoverlandbelow700hPa• UseofAMVsinthemiddletroposphere
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OSEFORHIMAWARI-8AMVUSINGMESO-SCALENWPSYSTEM
(MSM)
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ExperimentalDesignforMeso-scaleNWPsystem
29
Name Specification(Maindifferences)CNTL Aschemeofthe200kmthinningofOPE-AMVs
inthe3hourtimewindow
TEST CNTL+QCforHimawari-8AMVs(sameasaschemeofCNTL)+NOMTSAT-2AMVs
• Period– Summer2015
• Assimilation:From 7August to11September2015• Forecast:From7August to11September2015
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ResultofOSE(RainScoreandCaseStudyofheavyrain)
30
CNTL TEST
OBS
A case study of Kanto-Tohoku heavy rain (FT=03 at 03 UTC 9 September, 2015)
CNTLTEST
CNTLTEST
Equitable Threat Score (ETS)
Bias Score (BS)
Better
improved
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Incrementofgeopotentialheightandwindsfor850hPa at03UTC9September2015
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Strengthened convergence winds along E140 line
CNTL
TEST
Himawari-8 AMVs
NO AMV
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