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Stanley David Gedzelman and Michael Vollmer

We present simple radiative transfer models for the radiance and color of atmospheric optical phenomena. Skylight, halos, and rainbows are treated as singly scattered sunlight that is depleted by scattering as it passes through a plane-parallel atmosphere and a vertical rain shaft or a geometrically thin cloud layer. Skylight in a molecular atmosphere grades from deep blue at the zenith to pale blue near the horizon whenever the solar zenith angle φ sun ≤ 80°. Skylight near the horizon is orange resulting from wavelength-dependent scattering by air molecules and aerosol particles through a long oblique path through the atmosphere when the sun is low in the sky (φ sun ≥ 85°). Halos (and coronas) seen through clouds facing the sun are brightest for cloud optical depth τ cld ≈ cos(φ sun), and fade to obscurity for τ cld ≥ 5. Rainbows (and glories), seen by light that is backscattered from clouds, also appear most dramatic when 0.2 ≤ τ cld ≤ 1, but remain visible even in the thickest clouds.

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Paul Ricchiazzi, Shiren Yang, Catherine Gautier, and David Sowle

SBDART is a software tool that computes plane-parallel radiative transfer in clear and cloudy conditions within the earth's atmosphere and at the surface. All important processes that affect the ultraviolet, visible, and infrared radiation fields are included. The code is a marriage of a sophisticated discrete ordinate radiative transfer module, low-resolution atmospheric transmission models, and Mie scattering results for light scattering by water droplets and ice crystals. The code is well suited for a wide variety of atmospheric radiative energy balance and remote sensing studies. It is designed so that it can be used for case studies as well as sensitivity analysis. For small sets of computations or teaching applications it is available on the World Wide Web with a user-friendly interface. For sensitivity studies requiring many computations it is available by anonymous FTP as a well organized and documented FORTRAN 77 source code.

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Robert F. Cahalan, Lazaros Oreopoulos, Alexander Marshak, K. Franklin Evans, Anthony B. Davis, Robert Pincus, Ken H. Yetzer, Bernhard Mayer, Roger Davies, Thomas P. Ackerman, Howard W. Barker, Eugene E. Clothiaux, Robert G. Ellingson, Michael J. Garay, Evgueni Kassianov, Stefan Kinne, Andreas Macke, William O'hirok, Philip T. Partain, Sergei M. Prigarin, Alexei N. Rublev, Graeme L. Stephens, Frederic Szczap, Ezra E. Takara, Tamas Várnai, Guoyong Wen, and Tatiana B. Zhuravleva

The interaction of clouds with solar and terrestrial radiation is one of the most important topics of climate research. In recent years it has been recognized that only a full three-dimensional (3D) treatment of this interaction can provide answers to many climate and remote sensing problems, leading to the worldwide development of numerous 3D radiative transfer (RT) codes. The international Intercomparison of 3D Radiation Codes (I3RC), described in this paper, sprung from the natural need to compare the performance of these 3D RT codes used in a variety of current scientific work in the atmospheric sciences. I3RC supports intercomparison and development of both exact and approximate 3D methods in its effort to 1) understand and document the errors/limits of 3D algorithms and their sources; 2) provide “baseline” cases for future code development for 3D radiation; 3) promote sharing and production of 3D radiative tools; 4) derive guidelines for 3D radiative tool selection; and 5) improve atmospheric science education in 3D RT. Results from the two completed phases of I3RC have been presented in two workshops and are expected to guide improvements in both remote sensing and radiative energy budget calculations in cloudy atmospheres.

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A. J. Drummond and A. R. Karoli
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A. J. Illingworth, H. W. Barker, A. Beljaars, M. Ceccaldi, H. Chepfer, N. Clerbaux, J. Cole, J. Delanoë, C. Domenech, D. P. Donovan, S. Fukuda, M. Hirakata, R. J. Hogan, A. Huenerbein, P. Kollias, T. Kubota, T. Nakajima, T. Y. Nakajima, T. Nishizawa, Y. Ohno, H. Okamoto, R. Oki, K. Sato, M. Satoh, M. W. Shephard, A. Velázquez-Blázquez, U. Wandinger, T. Wehr, and G.-J. van Zadelhoff

domain; this 3D domain will be used as input to broadband radiative transfer models so that fluxes, heating rates, and radiances may be computed and TOA radiances and fluxes compared to those derived from EarthCARE’s broadband radiometer (BBR). Simulations described in this paper suggest that it will be possible to compute TOA fluxes and compare them with the BBR observations over each 10 km × 10 km scene to an accuracy of 10 W m –2 . The comparison between the modeled and observed BBR observations

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W. Paul Menzel, Timothy J. Schmit, Peng Zhang, and Jun Li

, advanced computers combined with better atmosphere radiative transfer theory opened the way to address important issues in weather forecasting and global climate change research. This included determining the initial conditions for NWP, the early warning and prediction of global weather processes and events, estimating the global radiation energy budget, monitoring global ocean conditions and ocean–atmosphere interactions, observing land and biosphere seasonal trends, evaluating the changes in

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James H. Mather and Jimmy W. Voyles

improved liquid water path retrievals when the liquid water path is small ( Turner et al. 2007 ). The SAS-Ze measures zenith radiance over the range 300 to 1,700 nm with a resolution of 2.4 to 3.5 nm (full width at half maximum) while the SAS-He uses a shadowband to measure hemispheric, direct-beam, and diffuse solar irradiance with the same spectral characteristics. The SAS-Ze and SAS-He are new instruments and are expected to provide constraints for radiative transfer models as well as retrievals of

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Stephen S. Leroy and Mark J. Rodwell

of data assimilation. The forward models associated with the anchor data should be made at least as accurate as the data themselves to take full advantage of the data's accuracy. Should improving accuracy of radiative transfer be an insurmountable problem, though, it may still be possible to discern model error when considering different types of highly accurate data that obey different remote sounding physics, including in situ data types, but are sensitive to the same atmospheric state

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Thomas J. Greenwald, R. Bradley Pierce, Todd Schaack, Jason Otkin, Marek Rogal, Kaba Bah, Allen Lenzen, Jim Nelson, Jun Li, and Hung-Lung Huang

defined in the GOES-R Product Definition and Users’ Guide (PUG; Horne 2014 ) using WRF-Chem V3.3.1 ( Grell et al. 2005 ) with the Goddard Chemistry Aerosol Radiation and Transport (GOCART) aerosol scheme ( Chin et al. 2000 , 2002 ) at 8-km horizontal grid spacing and with 34 vertical layers. Despite the relatively coarse horizontal resolution, convective clouds are explicitly forecasted so that signatures of fair weather cumulus and deep convective clouds can be included in the radiative transfer

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Ping Zhao, Xiangde Xu, Fei Chen, Xueliang Guo, Xiangdong Zheng, Liping Liu, Yang Hong, Yueqing Li, Zuo La, Hao Peng, Linzhi Zhong, Yaoming Ma, Shihao Tang, Yimin Liu, Huizhi Liu, Yaohui Li, Qiang Zhang, Zeyong Hu, Jihua Sun, Shengjun Zhang, Lixin Dong, Hezhen Zhang, Yang Zhao, Xiaolu Yan, An Xiao, Wei Wan, Yu Liu, Junming Chen, Ge Liu, Yangzong Zhaxi, and Xiuji Zhou

circulations. In the 1990s, a longer-term field experiment was conducted over the TP with the support of the Japanese Experiment on Asian Monsoon (JEXAM). It estimated the drag coefficient C d of surface momentum and the bulk transfer coefficient C h of surface sensible heat (SH) and revealed seasonal and interannual variations of the surface heat budget over the TP and their relationships with rainy seasons ( Chen 1999 ; Zhao and Chen 2000a , b ). Afterward, the Second Tibetan Plateau Atmospheric

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