Bottom Bottom # of edge of edge pressure GEOS-5 72 layers

layer (hPa) lumped togetherPTOP 0.010

1 0.066 42 0.211 43 0.617 44 1.651 45 4.077 46 9.293 47 19.792 48 28.368 29 40.175 2

10 56.388 211 78.512 2

%% START LUMPING LAYERS ABOVE HERE %%12 92.36613 108.66314 127.83715 150.39316 176.930

%% FIXED-PRESSURE LEVELS BEGIN ABOVE %%17 .18 .. Variable

46 .47 .

Variable Description Units Dimensions Source ProductNameLatitude Latitude deg (nLines,60) OMI OML1BR(U,V)GLongitude Longitude deg (nLines,60) Level1BTime Time s (nLines)PBLTOP PBLtopheight Pa (nLines,60) GEOS-5 tavg1_2d_slv_NxTROPPB Tropopauseheight(blendedestimate) Pa (nLines,60) assimilationU10M Eastwardwindat10m ms-1 (nLines,60)V10M Northwardwindat10m ms-1 (nLines,60)DELP Layerthickness Pa (nLines,60,47) GEOS-5 tavg_3d_asm_NvPS Surfacepressure Pa (nLines,60,47) assimilationT Airtemperature K (nLines,60,47)U Eastwardwindprofile ms-1 (nLines,60,47)V Northwardwindprofile ms-1 (nLines,60,47)

NASA GEOS-5 Assimilated Data Products for use in OMI Algorithms: Background and ApplicationsZachary T. Fasnacht, David P. Haffner, Ramaswamy A. Tiruchirapalli, Wenhan Qin, Alexander Vassilkov, Eun-Su Yang, Nick Gorkavyi

Science Systems and Applications, Inc., Lanham, MD USA

Description of the Product

Vertical Grid

Fields in the Current Product : OMxFPASM x:U,V=UV2,VIS

Spatial and Temporal Interpolation•  LinearInterpola-oninspaceand-meisusedtore-gridassimilateddatatotheOMImeasurements.

•  Originalresolu-on(MERRA-2,FP-IT)is0.50°x0.625°(figa.)

•  Timeresolu-on:1houror3hour.•  Timeaveragedassimila-onproductsareused.

•  OriginalGMAOdatareportedin72layerhybridsigmapressurecoordinates.

•  ToreducefilesizetheOMxFPASMproductsarere-gridedtoareducedgridsimilarto47layerGEOS-Chemgrid.

•  Ver-calresolu-onremainsunchangedfromsurfaceto176hPa.

•  Next8layersabovearelumpedby2.•  Remaininglayersarelumpedby4.•  Re-layereddataarecomputedbypressureweightedaverage.

•  PTOPis0.01hPa•  Indexingistopdown(L1isTOA).

GMAOproducesrobustreanalysisproductsfromdataassimila-onrunsoftheGEOS-5model.TheOMIcoreteamwillsoonreleasedataproductsthatreportthesedatainterpolatedinspaceand-metoeachOMImeasurementforuseinOMIretrievalalgorithmsandresearch/analysisapplica-ons.Meteorologicalfieldshavebeenpriori-zedbecausetheyareofexcellentqualityandwidelyused,butsugges-onsforinclusionofotherfieldsaremostwelcome. ResearchApplica?ons Variables AnalysisMethods

Emissions U,V,PS,PBLTOP Oversamplinganalysis

RetrievalErrorAnalysis T,O3Retrievalsensi-vitytes-ngUseas“Truth”profiles

RTMTheore?calStudies U10M,V10M,PS Oceanreflectancesimula-onPlumeTracking U,V Ver-calplumeheightes-ma-on

Chem+DynAnalysis T,U,V,PV,TROPPB PV-ThetamappingEs-ma-onofozoneholearea

OMI Standard Algorithm Applications

Data Availability and Access•  O2-O2ver-calcolumndensity(VCD)

highlysensi-vetoassumedtemperatureprofile.

AlgorithmsUseofAssimilatedDataFields

NotesCurrent Planned Possible

OMNO2 PS,U10M,V10M T PBLTOP 10mwindsviaGLER

OMTO3 T PS TROPPB,PV,O3 Temp.correc-on,aprioriprofileparameteriza-on

OMGLER PS,U10M,V10M T AccurateRayleigh&Oceansurfacemodeling

OMCLDRR - PS,U10M,V10M “”

OMAERUV - - PS,U10M,V10M

“”

OMSO2 - PS U,V Ver-calwindsforheight/trajectoryanalysis?

OMCLDO2N PS,U10M,V10M T 10mwindsviaGLER

Temperatures and Winds

SON

JJA

MAM

DJF

Uses for Research and Analysis

References

− FP-IT− CLIM

c. Figb.Thesensi-vityofO2-O2VCDtodifferencesinTprofilesis7%.Figc.showsassimilatedGMAOTdataisconsistentwithmonthlyclimatologyinTOMSV8,butGMAOdataprovidesvariability(1-σshownforFP-IT).

a.

d.

b.

Cold vs. Warm profile results in 7% ΔVCD at P=1 atm

Monthly Averaged T data at 45 N

Bosilovich,M.G.,R.Lucchesi,andM.Suarez,2016:MERRA-2:FileSpecifica-on.GMAOOfficeNoteNo.9(Version1.1),73pp,availablefromhjp://gmao.gsfc.nasa.gov/pubs/office_notes.

47-layer reduced GEOS-5 vertical grid

g.

Blackbarbs:vw≈0knots

Figd.GeometryDependentLER(GLER)data(len)simulatedoveroceansurfaceusingFP-ITwindspeed(right)showsreducedsunglintathigherwindspeeds.

f. h.

Figf.GLERsimula-onsforOMIgeometryusingGMAOwindsonJuly16,2005show"notches"inthespa-aldistribu-onofsun

glintontheoceansurfaceinregionsofverylowwindspeed.AnexampleofthisphenomenonisobservedinMODISradiances(Figg.)onAug.5,2017andcorrelatedwithlowwindspeedsmeasuredbyWindSat2intheregion(Fig.h.)

Higher latitudes

Tropical latitudes

FP-IT ForwardProcessingforInstrumentTeamsGMAO GlobalModelingandAssimila-onOfficeMERRA-2 Modern-EraRetrospec-veanalysisforResearchandApplica-ons,Version2

OMIScienceTeamMee-ngSep12-14,2017Greenbelt,MD

Acronyms

•  Version1oftheOMIUV-2FP-ITassimilatedproduct(OMUFPASM)willbeavailablesoonfortheen)remissioninAS70003.

•  VISchannelFP-ITdata(OMVFPASM)willbeavailableshortlyaner.•  OMIMERRA-2products(OMUM2ASM,OMVM2ASM)areplannedforanerFP-ITrelease.•  Contact:ZacharyFasnachtzachary.fasnacht@ssaihq.com

ThemainreasonforproducingOMIGEOS-5assimilateddataproductsistoputthedatainaformatforeasyusebystandardOMIalgorithms.AssimilatedFP-ITandMERRA-2productssupplyhighqualitymeteorologicalinforma-onforeachOMIorbit,providingmoreaccuraterepresenta-onofnaturalvariabilitythanclimatologicalsourcesofdata.

Therearealsonumerousanalysisapplica-onsforassimilatedGEOS-5outputreportedontheOMIpixels.TheOMIcoreteamhasbeguntoexplorethispoten-al,focusingfirstonimprovedtheore-calradia-vetransferworkforthemodelingtheoceansurface(sunglint),itseffectsontracegasretrievals,andonretrievalalgorithmerroranalysis.