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Vijayakumar S. Nair, K. Krishna Moorthy, S. Suresh Babu, and S. K. Satheesh

1. Introduction The optical properties of atmospheric aerosols such as the aerosol optical depth (AOD) and scattering ( σ ) and extinction coefficients, as well as information on their spectral dependencies, are quite important in estimating the radiative impacts and regional climate forcing of aerosols ( Houghton et al. 1995 ; Solomon et al. 2007 ). Aerosols are known to perturb the energy budget of the earth–atmosphere system, both directly by the scattering and absorption of radiation

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B. Kärcher, B. Mayer, K. Gierens, U. Burkhardt, H. Mannstein, and R. Chatterjee

high air traffic density ( Minnis 2003 ). The development of initially line-shaped contrails into cirrus clouds is not well understood; however, contrail cirrus may be the largest component in aviation radiative forcing ( Sausen et al. 2005 ). Given the large uncertainty in evaluating the contrail climate impact despite almost two decades of scientific study ( Forster et al. 2007 ), atmospheric research toward understanding the life cycle, spatial coverage, and microphysical and optical properties

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Bastiaan van Diedenhoven and Brian Cairns

1. Introduction To calculate the effect of ice clouds on Earth’s radiation budget, accurate optical properties are needed that are consistent with the range of ice crystal shapes and sizes present in natural ice clouds ( Stephens et al. 1990 ; Vogelmann and Ackerman 1995 ). Distributions of ice crystal shapes and sizes in clouds depend on many processes, such as depositional vapor growth, sublimation, crystal aggregation, riming, and crystal deposition, which in turn may depend on dynamics

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

asymmetry parameter ( Coakley and Chylek 1975 ; Fu 1996 ; Yang et al. 2000 ; Fu 2007 ). An increasing number of parameterizations for these optical properties of ice clouds are available. Such parameterizations generally relate the optical properties in selected wavelength bands in terms of predicted or imposed bulk characteristics of the ice, such as effective size, shape, and ice water content (e.g., Fu and Liou 1993 ; Fu 1996 ; Wyser and Yang 1998 ; Kristjánsson et al. 1999 ; Yang et al. 2000

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Dandan Zhao, Jinyuan Xin, Chongshui Gong, Xin Wang, Yongjing Ma, and Yining Ma

because of the unique geographical environment ( Wang and Zhang 2015 ). Therefore, several studies of northeastern Asian aerosols have been performed. Zhao et al. (2013) investigated the aerosol optical characteristics of four industrial cities in northeastern China based on data from a sun photometer and showed that unique “intercity” pollution exists between certain industrial cities. Xin et al. (2011) researched and analyzed the aerosol optical properties of the Bohai Rim region and supplied

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Ping Yang, Lei Bi, Bryan A. Baum, Kuo-Nan Liou, George W. Kattawar, Michael I. Mishchenko, and Benjamin Cole

habit prescription ( Baum et al. 2005 , 2011 ; Yue et al. 2007 ; Baran 2009 ). The resulting bulk-scattering properties are used in radiative transfer models to simulate the reflectance and transmittance associated with ice clouds over a range of conditions, and are tabulated in lookup tables (LUTs) for use in subsequent data reduction to infer ice cloud optical thickness and effective particle size from airborne or satellite observations ( Platnick et al. 2003 ; King et al. 2004 ; Huang et al

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T. H. Cheng, X. F. Gu, L. F. Chen, T. Yu, and G. L. Tian

. Optically thin cirrus have been identified as one of the major unsolved elements in weather and climate research, largely because of their unique optical properties and altitude ( McFarquhar et al. 2000 ). They affect the earth’s radiation budget because they reflect incoming solar radiation back to space and they absorb and re-emit terrestrial radiation ( Liou 1986 ; Lynch 1996 ). The radiative effect of the optically thin cirrus is determined by the optical and microphysical properties. Thus, studies

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Emma Järvinen, Martin Schnaiter, Guillaume Mioche, Olivier Jourdan, Valery N. Shcherbakov, Anja Costa, Armin Afchine, Martina Krämer, Fabian Heidelberg, Tina Jurkat, Christiane Voigt, Hans Schlager, Leonid Nichman, Martin Gallagher, Edwin Hirst, Carl Schmitt, Aaron Bansemer, Andy Heymsfield, Paul Lawson, Ugo Tricoli, Klaus Pfeilsticker, Paul Vochezer, Ottmar Möhler, and Thomas Leisner

1. Introduction Convective systems are an important source of ice particles in the upper troposphere (e.g., Jensen et al. 1996 ; Gayet et al. 2012a ; Frey et al. 2011 ) and the lowermost stratosphere ( de Reus et al. 2009 ). Ice particles found in the anvil outflows are usually formed in the lower and warmer part of the convective cell, and therefore their microphysical and optical properties differ from in situ formed ice particles (e.g., McFarquhar and Heymsfield 1996 ; Lawson et al

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C. G. Schmitt and A. J. Heymsfield

calculated for the dataset was 0.801 for solid crystals and 0.815 when the hollowness factor was considered. Following the same calculation as Schmitt et al. (2006) , consideration of the scattering properties of hollow crystals would yield a surface radiation increase of 2.5 W m −2 for a cirrus cloud with an optical depth of 0.5 for the wavelength range between 380 and 780 nm. 5. Summary and conclusions In this note we have reported the investigation of the frequency of hollows in the ends of bullet

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Takashi M. Nagao, Kentaroh Suzuki, and Takashi Y. Nakajima

. J. Atmos. Sci. , 47 , 1878 – 1893 . Nakajima , T. , M. D. King , J. D. Spinhirne , and L. F. Radke , 1991 : Determination of the optical thickness and effective radius of clouds from reflected solar radiation measurements. Part II: Marine stratocumulus observations . J. Atmos. Sci. , 48 , 728 – 750 . Nakajima , T. Y. , and T. Nakajima , 1995 : Wide-area determination of cloud microphysical properties from NOAA AVHRR measurements for FIRE and ASTEX regions . J. Atmos. Sci

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