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Alexander Smirnov, Brent N. Holben, Oleg Dubovik, Norm T. O'Neill, Thomas F. Eck, Douglas L. Westphal, Andreas K. Goroch, Christophe Pietras, and Ilya Slutsker

aerosol, often has been neglected in anthropogenic climate change considerations ( Andreae 1996 ). Although it is not presently possible to adequately characterize the influence of mineral dust on global climate, Li et al. (1996) suggest that it could be an important climate-forcing component over specific oceanic areas and other regions where dust concentration is high. Dust plays an important role in radiative processes and its optical properties are important for various estimations of radiative

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S. G. Bradley, C. D. Stow, and C. A. Lynch-Blosse

the calculation of mean rainfall intensity and gauge-derived optical depth. In all events gauges were in operation at the source, the detector, and at the midway point. The average rainfall intensity can be found by simple trapezoidal integration using weights based on the gauge spacing. The samples with zero rain, sometimes in sequence, were used to determine clear-air image properties. Figure 1 shows the difficulty with estimation of rainfall by point measurements when rainfall is spatially and

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Julia Marshall, Ulrike Lohmann, W. Richard Leaitch, Nicole Shantz, Lisa Phinney, Desiree Toom-Sauntry, and Sangeeta Sharma

° and 180° ( Carrico et al. 1998 ). The direct aerosol effect is determined by the optical properties of the aerosol particles, which are dependent upon the size, shape, and composition of the particles and the wavelength of the incident light. Measurements of the aerosol optical properties through the use of an integrating nephelometer or a particle soot absorption photometer (PSAP) are unable to apportion these effects into the contributions from individual chemical species ( Anderson et al. 1999

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R. M. Schotland and Huanling Hu

JOURNAL OF ATMOSPHERIC AND OCEANIC TECHNOLOGY VOLUME IA Supplement to "Optical Properties of a Plastic Pyranometer Head" R. M. SCHOTLAND AND HUANLING HU~ Institute of Atmospheric Physics, The University of Arizona. Tucson 85721 13 December 1983 and 15 February 19831. Introduction Schotland and Copp (1982) described the opticalcharacteristics of a newly designed two-step pyranometer head. The percentage error in the cosineresponse

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the Right Hon. LORD RAJLEIGH

the still colder ocean water creeping up from the depths of the Labrador current.NOTES, ABSTRACTS; AND REVIEWS.THE BLUE SKY AND THE OPTICAL PROPERTIES OF AIR.By the Right Hon. LORD RAJLEIGH.(Abstracted from Nature, vol. 105, pp. 5PA-5!!, July 8,1920.)The late Lord Rayleigh, from his demonstration that upon the basis of either the elastic-solid or the electro- magnetic theory a cloud of small particles (individually minute relative to the wave-length) is capable of scatter- in5 incident light in

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Masanori Saito, Ping Yang, Jiachen Ding, and Xu Liu

Abstract

A database (TAMUdust2020) of the optical properties of irregular aerosol particles is developed for applications to radiative transfer simulations involving aerosols, particularly dust and volcanic ash particles. The particle shape model assumes an ensemble of irregular hexahedral geometries to mimic complex aerosol particle shapes in nature. State-of-the-art light scattering computational capabilities are employed to compute the single-scattering properties of these particles for wide ranges of values of the size parameter, the index of refraction, and the degree of sphericity. The database therefore is useful for various radiative transfer applications over a broad spectral region from ultraviolet to infrared. Overall, agreement between simulations and laboratory/in-situ measurements is achieved for the scattering phase matrix and backscattering of various dust aerosol and volcanic ash particles. Radiative transfer simulations of active and passive spaceborne sensor signals for dust plumes with various aerosol optical depths and the effective particle sizes clearly demonstrate the applicability of the database for aerosol studies. In particular, the present database includes, for the first time, robust backscattering of nonspherical particles spanning the entire range of aerosol particle sizes, which shall be useful to appropriately interpret lidar signals related to the physical properties of aerosol plumes. Furthermore, thermal infrared simulations based on in-situ measured refractive indices of dust aerosol particles manifest the effects of the regional variations of aerosol optical properties. This database includes a user-friendly interface to obtain user-customized aerosol single-scattering properties with respect to spectrally dependent complex refractive index, size, and the degree of sphericity.

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Guangyao Dai, Xiaoye Wang, Kangwen Sun, Songhua Wu, Xiaoquan Song, Rongzhong Li, Jiaping Yin, and Xitao Wang

Abstract

A practical method for instrumental calibration and aerosol optical properties retrieval based on Coherent Doppler Lidar (CDL) and sun-photometer is presented in this paper. To verify its feasibility and accuracy, this method is applied into three field experiments in 2019 and 2020. In this method, multi-wavelength (440 nm, 670 nm, 870 nm and 1020 nm) Aerosol Optical Depth (AOD) from sun-photometer measurements are used to estimate AOD at 1550 nm and calibrate integrated CDL backscatter signal. Then, it is validated by comparing the retrieved calibrated AOD at 1550 nm from CDL signal and that from sun-photometer measurements. Well agreement between them with the correlation of 0.96, the RMSE of 0.0085 and the mean relative error of 22% is found. From the comparison results of these three experiments, sun-photometer is verified to be an effective reference instrument for the calibration of CDL return signal and the aerosol optical properties measurement with CDL is feasible. It is expected to promote the study on the aerosol flux and transport mechanism in the planetary boundary layer with the widely deployed CDLs.

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O. E. García, A. M. Díaz, F. J. Expósito, J. P. Díaz, A. Redondas, and T. Sasaki

is greater where the largest dust concentrations are found, such as Saharan plumes ( Herman et al. 2001 ; Torres and Bhartia 1999 ). The physical and optical properties of the atmospheric aerosols directly depend on the source regions and on the modifications that occur during the transport history. In the case of mineral dust, the two main source areas are the Saharan–Sahel and Asian deserts (the Taklimakan and Gobi Deserts), which show different mineralogical characteristics ( Sokolik and Toon

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Tyler J. Thorsen, David M. Winker, and Richard A. Ferrare

) = [ ⁡ ( ∂ DRX ∂ AOD Δ AOD − ∂ DRX ∂ SSA Δ SSA ) 2 + ⁡ ( ∂ DRX ∂ g Δ g ) 2 + ⁡ ( ∂ DRX ∂ a Δ a ) 2 + ( ∂ DRX ∂ COD ΔCOD ) 2 + ( ∂ DRF ∂ f ant Δ f ant ) 2 + ⁡ ( σ DRX z + σ DRX H + σ DRX λ ) 2 ] 1 / 2 , where the AOD is the aerosol optical depth, SSA is the aerosol single scattering albedo, g is the aerosol asymmetry factor, a is the surface albedo, COD is the cloud optical depth, and f ant is the anthropogenic fraction. All aerosol properties uncertainties and kernels are for a 550-nm wavelength. The

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Bastiaan van Diedenhoven, Andrew S. Ackerman, Ann M. Fridlind, and Brian Cairns

1. Introduction To properly represent the radiative properties of ice clouds in cloud and climate models, accurate optical properties of individual ice crystals are needed. For example, Vogelmann and Ackerman (1995) estimate that scattering asymmetry parameters must be known to within about 2%–5%, or about 0.02–0.04 in absolute terms, to constrain computed shortwave fluxes to within about 5%. For ice crystal scattering properties, in particular the asymmetry parameter, the shape and geometry

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