aerosol ver.cal structure as assessed by the micropulse lidar … · 2018. 7. 5. · nrb max: 1.22...
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LidarConstantCCalibra.on• NormalizedRela-veBacksca3ersignalisfoundbyapplyingthe
a=erpulse,dead-me,overlap,andrangecorrec-onstorawlidarsignal:
• Themolecularprofilesrelyonnearbyradiosondeprofiles.• Thecolumn-averagedlidarconstantCisfoundusingamolecular
fiFngalgorithmsearchingforthesta-s-callybesttopofaerosollayer.
• AeronetAOD:AirportSite(76malt.)andMobileSite(341malt.)• Theairportsitewascross-calibratedtothemobilesitetoincrease
thenumberoflidarCcalibra-ondatapoints.SolvingforLidarEx.nc.on• AmolecularfiFngalgorithmfindsthetopoftheaerosollayer,
whichiscombinedwiththepreviouslyfoundCsolvesforthecolumnop-caldepth.
• TheFernaldalgorithmisthenusedtofindtheex-nc-onprofile.• Sincethisinversionisdependentonthemolecularfit,the
coefficientofvaria-onR2determinesthequalityofthedata.• OnlyR2>0.5dataareconsidered.
Ascension Island Aeronet AOD (532 nm)
Airport Site (sea-level)0.1 0.2 0.3 0.4 0.5
AR
M S
ite (
365 m
)
0.1
0.2
0.3
0.4
0.5
DataFit: y = 0.915x - 0.0021 to 1 line
Results• ThemountainsofAscensionIslandandproximitytotheocean
encourageorographicli=ingofmoistair.• Consequently,Itiso=encloudyatthelidarmobilesite.• Mostoftheop-caldepthstemsfromthecloudyboundarylayer(0
to2km).Theal-tuderangeabovetheclouds(2to5km)thatcancontainsmokeandotheraerosolswasmostpollutedinOct.2017,andmostpris-neinlateMay-earlyJune.
Duringthebiomassburningseason:
• Thelowdepolariza-onra-oindicatesthattheaerosolsareprobablysmoke.
ElevatedaerosollayersalsooccurinFebandMarch(examplebelow).Thehigherdepolariza-onra-ossuggestthisisdustnotsmoke
Conclusion• Aerosolsaboveclouds,between2to5km,areo=enpresentat
Ascension• Anewfindingisthatthesearemorelikelytobedustinlateaustral
summer• Theever-presentcloudsprovidedasignificantchallengeiniden-fy
goodqualitylidardata.• Collabora-onwiththeCLARIFYteam,theNASAORACLESlidarteam
andthenewARMoverlapfunc-onhasallowedustoimproveourlidarex-nc-oncalcula-onandprovideconfidenceintheresults.
Introduc.on• AscensionIsland(8S,14W)isanidealloca-ontowitnessthelong-
rangetransportofsmokefromAfricanbiomassburninganddust.• TheDOEmicropulselidarprovidestheonlyconsistentindicatorof
ver-calstructureduringthe17-month-longLASICcampaign.• Thelidarex-nc-onprofileisderivedusinganFernald-based
inversionalgorithmdevelopedattheUniversityofMiamiandisconstrainedbyAERONET-derivedaerosolop-caldepth.
• Wecompareourlidarinvertedex-nc-onprofilestotheCLARIFYEXSCALABARaircra=in-situex-nc-onprofile.
Aim• ComparisonbetweentheDOElidarandin-situex-nc-onvalues• Observeaerosolstructureevolu-onbymonth.• Be3erunderstandhowtoobtainhighqualityex-nc-onretrievals
frommicropulselidar
AcknowledgementsManythankstoDOEASRDE-SC0013720LASICplanninggrantandDE-SC0018272formakingthisresearchpossible.
ContactInforma.onRodrigoDelgadillo:rod@physics.miami.edu
AerosolVer.calStructureasAssessedbytheMicropulseLidaruponAscensionIslandduringtheLASICCampaign
RodrigoDelgadillo,P.Zuidema,P.Muradyan,R.L.Coulter,S.J.Abel,C.Fox,R.A.Ferrare,S.P.BurtonUniv.ofMiami/RSMAS,Miami,FLDOEArgonneNtnlLabUKMetOfficeNASALangley
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18-Aug-2017
SNRB(z) = C(�a(z) + �m(z))e�2(⌧a(z)+⌧m(z))
MPL Particle Extinction
18:00
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20:15 22:30 00:45 03:00 05:15 07:30 09:45 12:00
05 Mar 2017
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05 Mar 2017UTC
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Ceilometer cloud base in red
MPL Particle Extinction
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21:45 01:30 05:15 09:00 12:45 16:30 20:15 00:0016 Aug 2016
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ComparisonwithCLARIFYIn-situEx.nc.on(EXSCALABAR)• MPLex-nc-onfor15minaverageoftherawlidardata:
• Thepost-deploymentoverlapcalibra-ondonebyARMattheSGPsitedifferssubstan-allyfromthepre-deploymentcalibra-ondonebytheMPLmanufacturerSigmaSpace.Thenewoverlapplaceslessweightwithintheboundarylayer,reducingthoseex-nc-ons.
• Thenewex-nc-onprofilesabove2kmhavever-calstructuresthatagreewiththosefromtheaircra=.
• Correc-ngthederivedcolumn-averagedlidarra-otobe65/sr,themeanlidarra-ooffree-troposphericsmokeat530nmderivedbytheNASAHighSpectralResolu-onLidar2duringORACLESSept2016,bringstheMPL-retrievedvaluesintoapproximateagreementwiththein-situex-nc-on.
Integrated Extinction for Entire Campaign with 3 day running average
10Jul
2016
25 9Aug2016
24 8Sep2016
23 8Oct
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20 7Mar2017
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21 5Jun
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20 4Aug2017
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18 2Nov2017
UTCIn
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od1: integrated from 0 to 2 kmod2: integrated from 2 to 5 km
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CloudyprofilesexcludedbyfiFngalgoritm
MPL: 25-Aug-2017 14:30Aircraft: 25-Aug-2017 14:17 to 14:31
Extinction [Mm-1]
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2016 Sigma Space Overlap (aod: 0.29, R2: 0.56, LR: 18.07 sr-1)
2018 ARM Overlap (aod: 0.09, R2: 0.49, LR: 13.54 sr-1)Aircraft RH 405 (aod: 0.21)Aircraft RH 660 (aod: 0.11)
LR Adjusted MPL (65 sr-1)
MPL: 01-Sep-2017 13:45Aircraft: 01-Sep-2017 13:26 to 13:48
Extinction [Mm-1]
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2016 Sigma Space Overlap (aod: 0.72, R2: 0.19, LR: 13.65 sr-1)
2018 ARM Overlap (aod: 0.38, R2: 0.24, LR: 25.04 sr-1)Aircraft RH 405 (aod: 0.53)Aircraft RH 660 (aod: 0.28)
LR Adjusted MPL (65 sr-1)
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