NASA GEOS-5 Assimilated Data Products for use in OMI...
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Bottom Bottom # of edge of edge pressure GEOS-5 72 layers layer (hPa) lumped together PTOP 0.010 1 0.066 4 2 0.211 4 3 0.617 4 4 1.651 4 5 4.077 4 6 9.293 4 7 19.792 4 8 28.368 2 9 40.175 2 10 56.388 2 11 78.512 2 %% START LUMPING LAYERS ABOVE HERE %% 12 92.366 13 108.663 14 127.837 15 150.393 16 176.930 %% FIXED-PRESSURE LEVELS BEGIN ABOVE %% 17 . 18 . . Variable 46 . 47 . Variable Description Units Dimensions Source Product Name Latitude Latitude deg (nLines,60) OMI OML1BR(U,V)G Longitude Longitude deg (nLines,60) Level 1B Time Time s (nLines) PBLTOP PBL top height Pa (nLines,60) GEOS-5 tavg1_2d_slv_Nx TROPPB Tropopause height (blended estimate) Pa (nLines,60) assimilation U10M Eastward wind at 10 m ms -1 (nLines,60) V10M Northward wind at 10 m ms -1 (nLines,60) DELP Layer thickness Pa (nLines,60,47) GEOS-5 tavg_3d_asm_Nv PS Surface pressure Pa (nLines,60,47) assimilation T Air temperature K (nLines,60,47) U Eastward wind profile ms -1 (nLines,60,47) V Northward wind profile ms -1 (nLines,60,47) NASA GEOS-5 Assimilated Data Products for use in OMI Algorithms: Background and Applications Zachary 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 • Linear Interpola-on in space and -me is used to re-grid assimilated data to the OMI measurements. • Original resolu-on (MERRA-2, FP-IT) is 0.50° x 0.625° (fig a.) • Time resolu-on: 1 hour or 3 hour. • Time averaged assimila-on products are used. • Original GMAO data reported in 72 layer hybrid sigma pressure coordinates. • To reduce file size the OMxFPASM products are re-grided to a reduced grid similar to 47 layer GEOS-Chem grid. • Ver-cal resolu-on remains unchanged from surface to 176 hPa. • Next 8 layers above are lumped by 2. • Remaining layers are lumped by 4. • Re-layered data are computed by pressure weighted average. • PTOP is 0.01 hPa • Indexing is top down (L1 is TOA). GMAO produces robust reanalysis products from data assimila-on runs of the GEOS-5 model. The OMI core team will soon release data products that report these data interpolated in space and -me to each OMI measurement for use in OMI retrieval algorithms and research/analysis applica-ons. Meteorological fields have been priori-zed because they are of excellent quality and widely used, but sugges-ons for inclusion of other fields are most welcome. Research Applica?ons Variables Analysis Methods Emissions U, V, PS, PBLTOP Oversampling analysis Retrieval Error Analysis T, O3 Retrieval sensi-vity tes-ng Use as “Truth” profiles RTM Theore?cal Studies U10M, V10M, PS Ocean reflectance simula-on Plume Tracking U, V Ver-cal plume height es-ma-on Chem+Dyn Analysis T, U, V, PV, TROPPB PV-Theta mapping Es-ma-on of ozone hole area OMI Standard Algorithm Applications Data Availability and Access • O2-O2 ver-cal column density (VCD) highly sensi-ve to assumed temperature profile. Algorithms Use of Assimilated Data Fields Notes Current Planned Possible OMNO2 PS, U10M, V10M T PBLTOP 10 m winds via GLER OMTO3 T PS TROPPB, PV, O3 Temp. correc-on, a priori profile parameteriza-on OMGLER PS, U10M, V10M T Accurate Rayleigh & Ocean surface modeling OMCLDRR - PS, U10M, V10M “” OMAERUV - - PS, U10M, V10M “” OMSO2 - PS U, V Ver-cal winds for height/ trajectory analysis? OMCLDO2N PS, U10M, V10M T 10 m winds via GLER Temperatures and Winds SON JJA MAM DJF Uses for Research and Analysis References − FP-IT − CLIM c. Fig b. The sensi-vity of O2-O2 VCD to differences in T profiles is 7%. Fig c. shows assimilated GMAO T data is consistent with monthly climatology in TOMS V8, but GMAO data provides variability (1-σ shown for FP-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, and M. Suarez, 2016: MERRA-2: File Specifica-on. GMAO Office Note No. 9 (Version 1.1), 73 pp, available from hjp://gmao.gsfc.nasa.gov/pubs/office_notes. 47-layer reduced GEOS-5 vertical grid g. Black barbs: v w ≈ 0 knots Fig d. Geometry Dependent LER (GLER) data (len) simulated over ocean surface using FP-IT wind speed (right) shows reduced sun glint at higher wind speeds. f. h. Fig f. GLER simula-ons for OMI geometry using GMAO winds on July 16, 2005 show "notches" in the spa-al distribu-on of sun glint on the ocean surface in regions of very low wind speed. An example of this phenomenon is observed in MODIS radiances (Fig g.) on Aug. 5, 2017 and correlated with low wind speeds measured by WindSat 2 in the region (Fig. h.) Higher latitudes Tropical latitudes FP-IT Forward Processing for Instrument Teams GMAO Global Modeling and Assimila-on Office MERRA-2 Modern-Era Retrospec-ve analysis for Research and Applica-ons, Version 2 OMI Science Team Mee-ng Sep 12-14, 2017 Greenbelt, MD Acronyms • Version 1 of the OMI UV-2 FP-IT assimilated product (OMUFPASM) will be available soon for the en)re mission in AS 70003. • VIS channel FP-IT data (OMVFPASM) will be available shortly aner. • OMI MERRA-2 products (OMUM2ASM, OMVM2ASM) are planned for aner FP-IT release. • Contact: Zachary Fasnacht [email protected] The main reason for producing OMI GEOS-5 assimilated data products is to put the data in a format for easy use by standard OMI algorithms. Assimilated FP-IT and MERRA-2 products supply high quality meteorological informa-on for each OMI orbit, providing more accurate representa-on of natural variability than climatological sources of data. There are also numerous analysis applica-ons for assimilated GEOS-5 output reported on the OMI pixels. The OMI core team has begun to explore this poten-al, focusing first on improved theore-cal radia-ve transfer work for the modeling the ocean surface (sun glint), its effects on trace gas retrievals, and on retrieval algorithm error analysis.
Transcript of NASA GEOS-5 Assimilated Data Products for use in OMI...
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:[email protected]
ThemainreasonforproducingOMIGEOS-5assimilateddataproductsistoputthedatainaformatforeasyusebystandardOMIalgorithms.AssimilatedFP-ITandMERRA-2productssupplyhighqualitymeteorologicalinforma-onforeachOMIorbit,providingmoreaccuraterepresenta-onofnaturalvariabilitythanclimatologicalsourcesofdata.
Therearealsonumerousanalysisapplica-onsforassimilatedGEOS-5outputreportedontheOMIpixels.TheOMIcoreteamhasbeguntoexplorethispoten-al,focusingfirstonimprovedtheore-calradia-vetransferworkforthemodelingtheoceansurface(sunglint),itseffectsontracegasretrievals,andonretrievalalgorithmerroranalysis.
