Aerosol Lidar

Aerosol Lidar System ntsuas
Lub aerosol lidar system ntsuas cov ntaub ntawv ntawm aerosol thiab / lossis huab backscatter ntawm 532 thiab 1064 nm thiab aerosol / huab depolarization ntawm 532 nm. Backscatter profiles ntawm ob lub wavelengths no muab cov ntaub ntawv ntawm cov txheeb ze concentration thiab spatial faib ntawm aerosol / huab hais. Kev sib piv ntawm aerosol / huab backscatter ntawm ob lub wavelengths muab qee qhov qhia txog qhov loj me. Kev ntsuas ntawm cov nyhuv depolarizing ntawm cov khoom (uas yog, qhov degree ntawm qhov polarization ntawm backscattered lub teeb los ntawm cov khoom sib txawv ntawm linear polarization ntawm lub teeb transmissions laser) muab ib qho kev qhia ntawm particle theem. Cov teeb liab uv raug xa mus rau arotel receiver assembly thiab 532- thiab 1064-nm cov teeb liab raug coj mus rau aerosol lidar receiver assembly. Nyob rau hauv lub aerosol lidar receiver, ib tug rotating shutter thaiv qhov muaj zog heev nyob ze-ntau 532- thiab 1064-nm teeb liab thiaj li yuav txo tau distortion nyob rau hauv lub kuj tsis muaj zog teeb liab los ntawm qhov chaw siab tshaj. Lub 532- thiab 1064-nm signals yog sib cais los ntawm ib tug dichroic beam splitter thiab lub 532-nm teeb liab yog ntxiv cais mus rau hauv orthogonal polarization Cheebtsam siv ib tug polarizing beam cube. Lub tshuab computer tswj ib nrab-yoj phaj nyob rau hauv pem hauv ntej ntawm lub polarizing beam lub voos xwmfab yog rotated thiaj li hais tias lub polarization ntawm 532 teeb liab yog parallel thiab perpendicular mus rau lub polarization ntawm kis laser pulses. Cov teeb liab ntawm ob qho tib si wavelengths thiab ob qho tib si 532-nm polarizations raug xa mus rau cov khoom ntes ntawm aerosol lidar cov ntaub ntawv khaws cia ntawm fiber ntau optic cables. Txhua lub teeb liab kho qhov muag, 1064-nm tag nrho backscatter thiab 532-nm thaum uas tig mus thiab perpendicularly polarized backscatter, yog coj mus rau ob cais detectors, nrog 10% mus rau ib tug detector thiab 90% mus rau lwm yam, nyob rau hauv thiaj li yuav txhawm rau ntsuas qhov tseeb dua ntawm cov teeb liab hla lawv cov dynamic ntau yam. Lub 532-nm rov qab yog ntsuas nrog cov duab-multiplier raj thiab cov 1064-nm rov qab yog ntsuas nrog avalanche photo-diodes. Vim muaj cov teeb liab siab kho qhov muag, tag nrho cov ntaub ntawv tau txais hauv hom analog, siv 12-ntsis analog-rau-digital converters. Lub cuab yeej ua haujlwm nyob rau hauv ob qho tib si nruab hnub thiab hmo ntuj teeb pom kev zoo, nrog me ntsis degradation hauv cov ntaub ntawv zoo thaum nruab hnub.

Aerosol Lidar System ntsuas
Lub aerosol lidar system ntsuas cov ntaub ntawv ntawm aerosol thiab / lossis huab backscatter ntawm 532 thiab 1064 nm thiab aerosol / huab depolarization ntawm 532 nm. Backscatter profiles ntawm ob lub wavelengths no muab cov ntaub ntawv ntawm cov txheeb ze concentration thiab spatial faib ntawm aerosol / huab hais. Kev sib piv ntawm aerosol / huab backscatter ntawm ob lub wavelengths muab qee qhov qhia txog qhov loj me. Kev ntsuas ntawm cov nyhuv depolarizing ntawm cov khoom (uas yog, qhov degree ntawm qhov polarization ntawm backscattered lub teeb los ntawm cov khoom sib txawv ntawm linear polarization ntawm lub teeb transmissions laser) muab ib qho kev qhia ntawm particle theem. Cov teeb liab uv raug xa mus rau arotel receiver assembly thiab 532- thiab 1064-nm cov teeb liab raug coj mus rau aerosol lidar receiver assembly. Nyob rau hauv lub aerosol lidar receiver, ib tug rotating shutter thaiv qhov muaj zog heev nyob ze-ntau 532- thiab 1064-nm teeb liab thiaj li yuav txo tau distortion nyob rau hauv lub kuj tsis muaj zog teeb liab los ntawm qhov chaw siab tshaj. Lub 532- thiab 1064-nm signals yog sib cais los ntawm ib tug dichroic beam splitter thiab lub 532-nm teeb liab yog ntxiv cais mus rau hauv orthogonal polarization Cheebtsam siv ib tug polarizing beam cube. Lub tshuab computer tswj ib nrab-yoj phaj nyob rau hauv pem hauv ntej ntawm lub polarizing beam lub voos xwmfab yog rotated thiaj li hais tias lub polarization ntawm 532 teeb liab yog parallel thiab perpendicular mus rau lub polarization ntawm kis laser pulses. Cov teeb liab ntawm ob qho tib si wavelengths thiab ob qho tib si 532-nm polarizations raug xa mus rau cov khoom ntes ntawm aerosol lidar cov ntaub ntawv khaws cia ntawm fiber ntau optic cables. Txhua lub teeb liab kho qhov muag, 1064-nm tag nrho backscatter thiab 532-nm thaum uas tig mus thiab perpendicularly polarized backscatter, yog coj mus rau ob cais detectors, nrog 10% mus rau ib tug detector thiab 90% mus rau lwm yam, nyob rau hauv thiaj li yuav txhawm rau ntsuas qhov tseeb dua ntawm cov teeb liab hla lawv cov dynamic ntau yam. Lub 532-nm rov qab yog ntsuas nrog cov duab-multiplier raj thiab cov 1064-nm rov qab yog ntsuas nrog avalanche photo-diodes. Vim muaj cov teeb liab siab kho qhov muag, tag nrho cov ntaub ntawv tau txais hauv hom analog, siv 12-ntsis analog-rau-digital converters. Lub cuab yeej ua haujlwm nyob rau hauv ob qho tib si nruab hnub thiab hmo ntuj teeb pom kev zoo, nrog me ntsis degradation hauv cov ntaub ntawv zoo thaum nruab hnub.

Basic Detection Principles ntawm Aerosol Lidar
Lub hauv paus ntsiab lus tshawb pom ntawm aerosol lidar yog tias tom qab lub laser tso tawm los ntawm lub laser mus rau hauv cov huab cua yog tawg thiab absorbed los ntawm aerosols thiab huab cua molecules, lub tawg ntho teeb liab tau txais los ntawm astronomical telescope, thiab ces finely faib, muab rho tawm thiab hloov dua siab tshiab rau hauv hluav taws xob. Cov teeb liab tau txais los ntawm kev siv daim npav ceev cov ntaub ntawv tau txais thiab khaws cia. Thaum kawg, los ntawm kev ua cov ntaub ntawv thiab kev hloov pauv, cov ntaub ntawv ntawm aerosol tuaj yeem tau txais. Feem ntau, lub lidar system suav nrog peb lub subsystems: laser emissions, teeb liab txais tos thiab nrhiav kom tau, thiab cov ntaub ntawv tau txais thiab ua.Lub laser emission subsystem muaj xws li ib tug laser thiab ib tug beam expander. Raws li hom khoom siv ua haujlwm, lasers tuaj yeem muab faib ua cov khoom, semiconductor, dye thiab roj lasers; beam expanders tuaj yeem nthuav qhov chaw laser thaum ua kom lub divergence lub me me. Lub teeb liab tau txais lub cev muaj xws li telescopes, apertures, spectroscopes, detectors, thiab lwm yam. Feem ntau siv telescopes muaj xws li Newtonian reflecting telescopes thiab Cassegrain reflecting telescopes; lub aperture yog muab tso rau ntawm lub tsom iav raj tsom iav, uas tuaj yeem txo cov suab nrov tom qab nyob rau saum ntuj thiab cuam tshuam ntawm ntau yam cuam tshuam; Tam sim no cov khoom siv feem ntau siv avalanche diodes (APD), photomultiplier hlab (PMT) thiab them nyiaj sib txuas (CCD), thiab lwm yam.

Aerosol Scattering Signal ntawm Aerosol Lidar
Lub aerosol scattering teeb liab muaj feem xyuam rau cov particle loj spectrum, wavelength, atmospheric refractive index, concentration, thiab lwm yam. Los ntawm kev ntsuas ncha signals nyob rau hauv txawv bands, aerosol optical zog yuav tau, xws li extinction coefficient, backscatter coefficient, radar ratio (LR) , aerosol optical depth (AOD), wavelength index, thiab lwm yam. Lub aerosol extinction coefficient thiab backscatter coefficient yog ob yam tsis paub txog ntawm lidar sib npaug. Qhov loj dua qhov backscattering coefficient yog, qhov muaj zog tshaj qhov muaj peev xwm tawg ntawm cov khoom nyob rau hauv qhov chaw, thiab vice versa. Muaj ntau yam uas cuam tshuam rau backscattering coefficient, xws li particle concentration thiab particle radius, thiab kev sib raug zoo ntawm lawv yog complex. Lub aerosol extinction coefficient qhia txog lub peev xwm ntawm aerosol extinction. Lub Ångström wavelength Performance index yog ib qho tseem ceeb parameter ntsuas qhov luaj li cas ntawm cov ' meter ' s scattering hais. Tus nqi ntawm qhov ntsuas wavelength feem ntau yog nyob rau hauv thaj tsam ntawm {{{0}}}.0, uas yog ze ze rau qhov loj ntawm aerosol, nthuav tawm qhov kev vam meej ntawm kev ploj mus ntawm lub wavelength ntawm teeb meem teeb meem. Thaum lub aerosol particle radius loj piv rau qhov teeb meem laser wavelength.

Aerosol Lidar yog ib qho cuab yeej siv tau rau kev siv cov chaw taws teeb pom kev pom ntawm Atmospheric Aerosols
Lidar yog ib qho cuab yeej txhim khu kev qha rau cov chaw taws teeb sensing nrhiav pom ntawm atmospheric aerosols. Cov qauv tsim, kev qhia tshwj xeeb, kev soj ntsuam kev sib tw, thiab lub hauv paus ntsiab lus ntawm kev tshawb nrhiav tau qhia. Txhawm rau kom ntseeg tau qhov tseeb thiab kev ntseeg siab ntawm lidar soj ntsuam cov ntaub ntawv, cov ntsiab lus calibration, thiab cov txheej txheem ntawm lidar tau thov, suav nrog kev kho, thiab gluing ntawm cov ntaub ntawv qub, kev sib tsoo ntawm kev xa tawm thiab tau txais optical axes, kev ntsuam xyuas cov teeb liab saturation, kev kho ntawm molecular rayleigh haum thiab kev txiav txim siab ntawm depolarization ratio kho qhov tseem ceeb. Cov txiaj ntsig kev tshawb nrhiav pom pom qhov kev ntseeg siab ntawm lidar uas tuaj yeem tau txais cov yam ntxwv ntawm lub cev thiab qhov sib txawv ntawm qhov haze. Cov profiles ntawm aerosol extinction coefficient, muaj peev xwm kub thiab txheeb ze av noo tuaj yeem siv tau zoo los txheeb xyuas qhov haze thickness thiab cuam tshuam ntawm cov av noo ntawm cov khoom aerosol. Cov ntaub ntawv ntawm huab cua zoo saib pom tau hais tias pm10 yog cov pa phem tseem ceeb thiab qhov piv ntawm pm2.5 / pm10 yog qhov cuam tshuam tsis zoo nrog cov av noo. Huab cua thiab huab cua cuam tshuam los ntawm aerosol-kawg thiab aerosol- huab sib cuam tshuam. Qhov ncaj qha huab cua cuam tshuam ntawm aerosols yog cuam tshuam rau qhov sib npaug ntawm lub ntiaj teb-kho huab cua hluav taws xob los ntawm kev tawg thiab nqus hnub ci hluav taws xob, yog li cuam tshuam rau kev hloov pauv huab cua. Thiab qhov tsis ncaj qha huab cua cuam tshuam ntawm aerosols yog ua raws li lub hauv paus ntsiab lus ntawm huab cua, uas hloov cov khoom kho qhov muag ntawm huab, huab npaum li cas thiab huab lifespan, thiab tom qab ntawd cuam tshuam rau lub ntiaj teb-kho huab cua hluav taws xob sib npaug. Hauv kev xaus, atmospheric aerosols muaj kev cuam tshuam tseem ceeb rau huab cua, huab cua, nyob ib puag ncig thiab tib neeg kev noj qab haus huv.