Modeling of the scattering and radiative properties of nonspherical dust-like aerosols

Yang, Ping; Qian, Feng; Hong, Gang; Kattawar, George W.; Wiscombe, W. J.; Mishchenko, Michael I.; Dubovik, Оleg; László, István; Sokolik, I. N.

doi:10.1016/j.jaerosci.2007.07.001

Cited by 197 publications

(152 citation statements)

References 65 publications

(91 reference statements)

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“…Optical properties of large spheroids were calculated with the improved geometric optics method (IGOM) code provided by Yang et al (2007) and Bi et al (2009). In general, this approximation is most accurate if the particle and its structures are large compared to the wavelength.…”

Section: Improved Geometric Optics Methods (Igom)mentioning

confidence: 99%

MOPSMAP v1.0: a versatile tool for the modeling of aerosol optical properties

Gasteiger

Wiegner²

2018

Geosci. Model Dev.

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Abstract. The spatiotemporal distribution and characterization of aerosol particles are usually determined by remotesensing and optical in situ measurements. These measurements are indirect with respect to microphysical properties, and thus inversion techniques are required to determine the aerosol microphysics. Scattering theory provides the link between microphysical and optical properties; it is not only needed for such inversions but also for radiative budget calculations and climate modeling. However, optical modeling can be very time-consuming, in particular if nonspherical particles or complex ensembles are involved.In this paper we present the MOPSMAP package (Modeled optical properties of ensembles of aerosol particles), which is computationally fast for optical modeling even in the case of complex aerosols. The package consists of a data set of pre-calculated optical properties of single aerosol particles, a Fortran program to calculate the properties of userdefined aerosol ensembles, and a user-friendly web interface for online calculations. Spheres, spheroids, and a small set of irregular particle shapes are considered over a wide range of sizes and refractive indices. MOPSMAP provides the fundamental optical properties assuming random particle orientation, including the scattering matrix for the selected wavelengths. Moreover, the output includes tables of frequently used properties such as the single-scattering albedo, the asymmetry parameter, or the lidar ratio. To demonstrate the wide range of possible MOPSMAP applications, a selection of examples is presented, e.g., dealing with hygroscopic growth, mixtures of absorbing and non-absorbing particles, the relevance of the size equivalence in the case of nonspherical particles, and the variability in volcanic ash microphysics.The web interface is designed to be intuitive for expert and nonexpert users. To support users a large set of default settings is available, e.g., several wavelength-dependent refractive indices, climatologically representative size distributions, and a parameterization of hygroscopic growth. Calculations are possible for single wavelengths or user-defined sets (e.g., of specific remote-sensing application). For expert users more options for the microphysics are available. Plots for immediate visualization of the results are shown. The complete output can be downloaded for further applications. All input parameters and results are stored in the user's personal folder so that calculations can easily be reproduced. The web interface is provided at https://mopsmap.net (last access: 9 July 2018) and the Fortran program including the data set is freely available for offline calculations, e.g., when large numbers of different runs for sensitivity studies are to be made.

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Section: Improved Geometric Optics Methods (Igom)mentioning

confidence: 99%

MOPSMAP v1.0: a versatile tool for the modeling of aerosol optical properties

Gasteiger

Wiegner²

2018

Geosci. Model Dev.

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“…A variation in single scattering albedo (SSA) of ±3 % (based on a reference value of 0.90) results in a 10 % error for moderate AOD (τ = 0.5 at 0.67 µm) and a 32 % error for large AODs (τ = 1.5) (Zhang et al, 2001). Lee et al (2012) used a triaxial ellipsoidal database of dust (Yang et al, 2007) and inversion data from the AErosol RObotic NETwork (AERONET) to greatly improve the AOD retrieved using the MODIS dark target algorithm with regards to its Pearson coefficient (from 0.92 to 0.93), regression slope (from 0.85 to 0.99), and the percentage of data within an expected error bound (from 62 to 64 %).…”

Section: Introductionmentioning

confidence: 99%

Aerosol optical properties derived from the DRAGON-NE Asia campaign, and implications for a single-channel algorithm to retrieve aerosol optical depth in spring from Meteorological Imager (MI) on-board the Communication, Ocean, and Meteorological Satellite (COMS)

Kim

Jeong

et al. 2016

Atmos. Chem. Phys.

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Abstract. An aerosol model optimized for northeast Asia is updated with the inversion data from the Distributed Regional Aerosol Gridded Observation Networks (DRAGON)-northeast (NE) Asia campaign which was conducted during spring from March to May 2012. This updated aerosol model was then applied to a single visible channel algorithm to retrieve aerosol optical depth (AOD) from a Meteorological Imager (MI) on-board the geostationary meteorological satellite, Communication, Ocean, and Meteorological Satellite (COMS). This model plays an important role in retrieving accurate AOD from a single visible channel measurement. For the single-channel retrieval, sensitivity tests showed that perturbations by 4 % (0.926 ± 0.04) in the assumed single scattering albedo (SSA) can result in the retrieval error in AOD by over 20 %. Since the measured reflectance at the top of the atmosphere depends on both AOD and SSA, the overestimation of assumed SSA in the aerosol model leads to an underestimation of AOD. Based on the AErosol RObotic NETwork (AERONET) inversion data sets obtained over East Asia before 2011, seasonally analyzed aerosol optical properties (AOPs) were categorized by SSAs at 675 nm of 0.92 ± 0.035 for spring (March, April, and May). After the DRAGON-NE Asia campaign in 2012, the SSA during spring showed a slight increase to 0.93 ± 0.035. In terms of the volume size distribution, the mode radius of coarse particles was increased from 2.08 ± 0.40 to 2.14 ± 0.40. While the original aerosol model consists of volume size distribution and refractive indices obtained before 2011, the new model is constructed by using a total data set after the DRAGON-NE Asia campaign. The large volume of data in high spatial resolution from this intensive campaign can be used to improve the representative aerosol model for East Asia. Accordingly, the new AOD data sets retrieved from a single-channel algorithm, which uses a precalculated look-up table (LUT) with the new aerosol model, show an improved correlation with the measured AOD during the DRAGON-NE Asia campaign. The correlation between the new AOD and AERONET value shows a regression slope of 1.00, while the comparison of the original AOD data retrieved using the original aerosol model shows a slope of 1.08. The change of y-offset is not significant, and the correlation coefficients for the comparisons of the original and new AOD are 0.87Published by Copernicus Publications on behalf of the European Geosciences Union. M. Kim et al.: AOD retrieval using GEO measurement during DRAGON-NE Asia 2012and 0.85, respectively. The tendency of the original aerosol model to overestimate the retrieved AOD is significantly improved by using the SSA values in addition to size distribution and refractive index obtained using the new model.

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“…Certain spheroidal shape parameterizations can substantially diminish the differences between experimental and modeled values of the atmospheric aerosol radiative forcing (Otto et al, 2009). Yang et al (2007) estimated the influence of prolate spheroidal model particles on the radiation field and stated that the nonsphericity of particles affects short-wave radiation significantly, but has no impact on long-wave radiation. Pilinis and Li (1998) estimated the radiative forcing of prolate spheroidal model particles, and found that assuming such shapes can result in a radiative forcing up to three times larger than for spherical shapes when the solar zenith angle nears zero.…”

Section: Introductionmentioning

confidence: 99%

Aerosol radiative forcing during African desert dust events (2005–2010) over Southeastern Spain

et al. 2012

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Abstract. The daily (24 h) averages of the aerosol radiative forcing (ARF) at the surface and the top of the atmosphere (TOA) were calculated during desert dust events over Granada (southeastern Spain) from 2005 to 2010. A radiative transfer model (SBDART) was utilized to simulate the solar irradiance values (0.31-2.8 µm) at the surface and TOA, using as input aerosol properties retrieved from CIMEL sun photometer measurements via an inversion methodology that uses the sky radiance measurements in principal plane configuration and a spheroid particle shape approximation. This inversion methodology was checked by means of simulated data from aerosol models, and the derived aerosol properties were satisfactorily compared against well-known AERONET products. Good agreement was found over a common spectral interval (0.2-4.0 µm) between the simulated SBDART global irradiances at surface and those provided by AERONET. In addition, simulated SBDART solar global irradiances at the surface have been successfully validated against CM-11 pyranometer measurements. The comparison indicates that the radiative transfer model slightly overestimates (mean bias of 3 %) the experimental solar global irradiance. These results show that the aerosol optical properties used to estimate ARF represent appropriately the aerosol properties observed during desert dust outbreak over the study area. The ARF mean monthly values computed during desert dust events ranged from −13 ± 8 W m −2 to −34 ± 15 W m −2 at surface, from −4 ± 3 W m −2 to −13 ± 7 W m −2 at TOA and from +6 ± 4 to +21 ± 12 W m −2 in the atmosphere. We have checked if the differences found in aerosol optical properties among desert dust sectors translate to differences in ARF. The mean ARF at surface (TOA) were −20 ± 12 (−5 ± 5) W m −2 , −21 ± 9 (−7 ± 5) W m −2 and −18 ± 9 (−6 ± 5) W m −2 for sector A (northern Morocco; northwestern Algeria), sector B (western Sahara, northwestern Mauritania and southwestern Algeria), and sector C (eastern Algeria, Tunisia), respectively. The Kolmogorov-Smirnov statistical test revealed that daily ARF values at TOA for sector A were significantly different from the other two sectors, likely as a result of the lower values of single scattering albedo obtained for sector A. The mean values of aerosol radiative forcing efficiency at surface (TOA) were −74 ± 12 W m −2 (−17 ± 7 W m −2 ) for sector A, −70 ± 14 W m −2 (−20 ± 9 W m −2 ) for sector B, and −65 ± 16 W m −2 (−22 ± 10 W m −2 ) for sector C, and thus comparable between the three sectors in all seasons.

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Modeling of the scattering and radiative properties of nonspherical dust-like aerosols

Cited by 197 publications

References 65 publications

MOPSMAP v1.0: a versatile tool for the modeling of aerosol optical properties

MOPSMAP v1.0: a versatile tool for the modeling of aerosol optical properties

Aerosol optical properties derived from the DRAGON-NE Asia campaign, and implications for a single-channel algorithm to retrieve aerosol optical depth in spring from Meteorological Imager (MI) on-board the Communication, Ocean, and Meteorological Satellite (COMS)

Aerosol radiative forcing during African desert dust events (2005–2010) over Southeastern Spain

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