Retrievals of aerosol optical and microphysical properties from Imaging Polar Nephelometer scattering measurements

Espinosa, W. Reed; Remer, L. A.; Dubovik, Оleg; Ziemba, L. D.; Beyersdorf, A. J.; Orozco, D.; Schuster, Gregory L.; Lapyonok, Tatyana; Fuertes, David; Martins, J. V.

doi:10.5194/amt-10-811-2017

Cited by 66 publications

(62 citation statements)

References 49 publications

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“…The inversion is initialized using a priori model emissions plus a spatially uniform value of 10 −4 for DD, 10 −6 for BC and 5 × 10 −6 for OC over land grid boxes where S a = 0; this allows for the detection of new sources and performs satisfactorily even at locations where the a priori knowledge of aerosol emission is poor (Chen et al, 2018). In this study, the a priori DD emission is based upon the mineral dust entrainment and deposition (DEAD) scheme (Zender et al, 2003) and the GOCART dust source function (Ginoux et al, 2001) that was implemented in GEOS-Chem model by Fairlie et al (2007). We adopted the improved fine mode dust contribution scheme by Zhang et al (2013) for both inversion and simulation.…”

Section: Geos-chem Inverse Modeling Frameworkmentioning

confidence: 99%

Constraining global aerosol emissions using POLDER/PARASOL satellite remote sensing observations

et al. 2019

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We invert global black carbon (BC), organic carbon (OC) and desert dust (DD) aerosol emissions from POLDER/PARASOL spectral aerosol optical depth (AOD) and aerosol absorption optical depth (AAOD) using the GEOS-Chem inverse modeling framework. Our inverse modeling framework uses standard a priori emissions to provide a posteriori emissions that are constrained by POLDER/PARASOL AODs and AAODs. The following global emission values were retrieved for the three aerosol components: 18.4 Tg yr −1 for BC, 109.9 Tg yr −1 for OC and 731.6 Tg yr −1 for DD for the year 2010. These values show a difference of +166.7 %, +184.0 % and −42.4 %, respectively, with respect to the a priori values of emission inventories used in "standard" GEOS-Chem runs. The model simulations using a posteriori emissions (i.e., retrieved emissions) provide values of 0.119 for global mean AOD and 0.0071 for AAOD at 550 nm, which are +13.3 % and +82.1 %, respectively, higher than the AOD and AAOD obtained using the a priori values of emissions. Additionally, the a posteriori model simulation of AOD, AAOD, single scattering albedo, Ångström exponent and absorption Ångström exponent show better agreement with independent AERONET, MODIS and OMI measurements than the a priori simulation. Thus, this study suggests that using satellite-constrained global aerosol emissions in aerosol transport models can improve the accuracy of simulated global aerosol properties.

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Section: Geos-chem Inverse Modeling Frameworkmentioning

confidence: 99%

Constraining global aerosol emissions using POLDER/PARASOL satellite remote sensing observations

et al. 2019

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“…This type of instrument uses a single detector with a simple, relatively compact design that does not require any moving parts and has great potential for field measurements that require higher time resolution. The first polarized imaging nephelometer used for field measurements employed a wide-angle lens and charge-coupled device (CCD) to record the scattering phase function under two orthogonal linear polarization conditions at three wavelengths (473, 532, and 671 nm) and derive both the phase function and degree of linear polarization across the visible spectral region (Dolgos and Martins, 2014;Espinosa et al, 2017). This instrument was deployed on the NASA DC8 aircraft for the Deep Convective Clouds and Chemistry (DC3) campaign in 2012 (Barth et al, 2015) and the Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC 4 RS) mission in 2014 (Toon et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Investigating biomass burning aerosol morphology using a laser imaging nephelometer

et al. 2018

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Abstract. Particle morphology is an important parameter affecting aerosol optical properties that are relevant to climate and air quality, yet it is poorly constrained due to sparse in situ measurements. Biomass burning is a large source of aerosol that generates particles with different morphologies. Quantifying the optical contributions of non-spherical aerosol populations is critical for accurate radiative transfer models, and for correctly interpreting remote sensing data. We deployed a laser imaging nephelometer at the Missoula Fire Sciences Laboratory to sample biomass burning aerosol from controlled fires during the FIREX intensive laboratory study. The laser imaging nephelometer measures the unpolarized scattering phase function of an aerosol ensemble using diode lasers at 375 and 405 nm. Scattered light from the bulk aerosol in the instrument is imaged onto a chargecoupled device (CCD) using a wide-angle field-of-view lens, which allows for measurements at 4-175 • scattering angle with ∼ 0.5 • angular resolution. Along with a suite of other instruments, the laser imaging nephelometer sampled fresh smoke emissions both directly and after removal of volatile components with a thermodenuder at 250 • C. The total integrated aerosol scattering signal agreed with both a cavity ring-down photoacoustic spectrometer system and a traditional integrating nephelometer within instrumental uncertainties. We compare the measured scattering phase functions at 405 nm to theoretical models for spherical (Mie) and fractal (Rayleigh-Debye-Gans) particle morphologies based on the size distribution reported by an optical particle counter.Results from representative fires demonstrate that particle morphology can vary dramatically for different fuel types. In some cases, the measured phase function cannot be described using Mie theory. This study demonstrates the capabilities of the laser imaging nephelometer instrument to provide realtime, in situ information about dominant particle morphology, which is vital for understanding remote sensing data and accurately describing the aerosol population in radiative transfer calculations.

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“…CC BY 4.0 License. applied to measurements from many different types of instruments (Benavent-Oltra et al, 2019;Espinosa et al, 2017Espinosa et al, , 2018Román et al, 2018;Titos et al, 2019;Torres et al, 2017), but the most pertinent to AirHARP are the previous applications of GRASP to POLDER-3 on PARASOL (Chen et al, 2018(Chen et al, , 2019Dubovik et al, 2011;Frouin et al, 2019;Li et al, 2019) 215 because of its familiar polarization, multi-wavelength, and multi-angle sampling characteristics.…”

Section: Generalized Retrieval Of Aerosol and Surface Properties (Grasp)mentioning

confidence: 99%

Retrieval of aerosol properties from Airborne Hyper Angular Rainbow Polarimeter (AirHARP) observations during ACEPOL 2017

Puthukkudy¹,

Martins²,

Remer³

et al. 2020

Preprint

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Multi-angle polarimetric (MAP) imaging of Earth scenes can be used for the retrieval of microphysical and optical parameters of aerosols and clouds. The Airborne Hyper-Angular Rainbow Polarimeter (AirHARP) is an aircraft MAP 15 instrument with the hyper-angular imaging capability of 60 along-track viewing angles at 670 nm, and 20 along-track viewing angles at other wavelengths 440, 550, 870 nm across the full 114 ̊ (94 ) along-track (cross-track) field-of-view. Here we report the retrieval of aerosol properties using the Generalized Retrieval of Aerosols and Surface Properties (GRASP) algorithm applied to AirHARP observations collected during the NASA Aerosol Characterization from Polarimeter and Lidar (ACEPOL) campaign in October -November 2017. The retrieved aerosol properties include spherical fraction (SF), aerosol volume 20 concentration in multiple size distribution modes, and with sufficient aerosol loading, complex aerosol refractive index. From these primary retrievals, we derive aerosol optical depth (AOD), Angstrom exponent (AE), and single scattering albedo (SSA). AOD retrieved from AirHARP measurements are compared with the High Spectral Resolution LiDAR-2 (HSRL2) AOD measurements at 532 nm and validated with measurements from collocated Aerosol Robotic NETwork (AERONET) stations. A good correlation with HSRL2 ( = 0.940, | | = 0.062) and AERONET AOD (0.013 ≤ Mean Absolute Error ( ) ≤ 25 0.017, 0.013 ≤ | | ≤ 0.017) measurements is observed for the collocated points. Forest fire smoke intercepted during ACEPOL provided a situation with sufficient aerosol loading to retrieve the real part of the refractive index (RRI) of 1.55 and the imaginary part of the refractive index (IRI) of 0.024 The derived SSAs for this case are 0.87, 0.86, 0.84, 0.81 at wavelengths of 440 nm, 550 nm, 670 nm, and 870 nm, respectively. Finer particles with an average AE of 1.53, volume median radius of 0.157 µm and standard deviation of 0.55 µm for fine mode is observed for the same smoke plume. These results serve as a 30 proxy for the scale and detail of aerosol retrievals that are anticipated from future space mission data, as :HARP CubeSat (mission begins 2020) and HARP2 (aboard the NASA PACE mission with launch in 2023) are near duplicates of AirHARP and are expected to provide the same level of aerosol characterization.

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Retrievals of aerosol optical and microphysical properties from Imaging Polar Nephelometer scattering measurements

Cited by 66 publications

References 49 publications

Constraining global aerosol emissions using POLDER/PARASOL satellite remote sensing observations

Constraining global aerosol emissions using POLDER/PARASOL satellite remote sensing observations

Investigating biomass burning aerosol morphology using a laser imaging nephelometer

Retrieval of aerosol properties from Airborne Hyper Angular Rainbow Polarimeter (AirHARP) observations during ACEPOL 2017

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