Search Results

You are looking at 11 - 20 of 7,603 items for :

  • Optical properties x
  • All content x
Clear All
Anthony J. Baran, Peter Hill, Kalli Furtado, Paul Field, and James Manners

underestimated by those models ( Baran 2012 ). Moreover, the parameterization of high clouds can affect the amount of low clouds predicted by the model through the vertical profile of radiative heating in the model, as shown by McFarquhar et al. (2003) . To quantify the role of the ice cloud in the radiative coupling between the atmosphere and cloud, it is of primary importance to construct accurate parameterizations of its bulk optical properties. Unfortunately, this is currently far from being achieved

Full access
R. Paul Lawson, Brad A. Baker, Patrick Zmarzly, Darren O’Connor, Qixu Mo, Jean-Francois Gayet, and Valery Shcherbakov

) suggest that using the wrong scattering phase function in retrieving cloud optical thickness can result in an overestimation or underestimation of optical thickness by more than a factor of 3. Detailed measurements of the size, shape, and scattering phase function of ice crystals at SPS can be adapted to studies of the optical properties of ice crystals in cirrus and other ice clouds. The elevation of SPS is approximately 2.8 km from mean sea level (MSL), and the temperature in the first 5 km MSL of

Full access
Michael E. Feinholz, Stephanie J. Flora, Mark A. Yarbrough, Keith R. Lykke, Steven W. Brown, B. Carol Johnson, and Dennis K. Clark

1. Introduction The optical properties of seawater reflect its composition. Under natural illumination from sunlight, radiometric measurements of the light leaving the ocean contain information about the nature and concentration of dissolved and suspended materials. The optical properties of the ocean can be related to meaningful physical and biogeochemical data products such as the concentration of phytoplankton chlorophyll- a through bio-optical algorithms. Quantitative measurements of

Full access
Wayne H. Slade, Emmanuel Boss, Giorgio Dall’Olmo, M. Rois Langner, James Loftin, Michael J. Behrenfeld, Collin Roesler, and Toby K. Westberry

optical absorption, attenuation, and backscattering coefficients. These quantities can be used to validate remotely sensed optical parameters and to estimate biomass and, using variable fluorescence, the physiological state of phytoplankton (e.g., Mueller et al. 2003 ; Behrenfeld and Boss 2003 ), as well as to provide constraints on particulate and dissolved pools and properties in ecosystem models (e.g., Fujii et al. 2007 ). Spectral particulate absorption and attenuation have also been used to

Full access
Gang Hong, Ping Yang, Bo-Cai Gao, Bryan A. Baum, Yong X. Hu, Michael D. King, and Steven Platnick

1. Introduction High clouds occur frequently over the Tropics (e.g., Liou 1986 ; Rossow and Schiffer 1999 ; Wylie et al. 1994 , 2005 ; Liu et al. 1995 ; Wang et al. 1996 , 1998 ; Wylie and Menzel 1999 ; Dessler and Yang 2003 ; Luo and Rossow 2004 ; Stubenrauch et al. 2006 ). The effect of high clouds on the climate system is highly sensitive to their optical and microphysical properties (e.g., Stephens et al. 1990 ; Liu and Curry 1999 ; McFarquhar et al. 2002 ). Cloud

Full access
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

Full access
Anne Garnier, Jacques Pelon, Philippe Dubuisson, Michaël Faivre, Olivier Chomette, Nicolas Pascal, and David P. Kratz

calculations ( Ackerman et al. 1995 ; Rädel et al. 2003 ; Kahn et al. 2004 ; Pavolonis 2010 ; Stubenrauch et al. 2006 ; Wang et al. 2011 ; Wei et al. 2004 ; Yue et al. 2007 ). In the framework of the CALIPSO mission, we have chosen to use selected range-resolved lidar inputs in a standard split-window technique to provide a fast retrieval of cirrus optical (emissivity and optical depth) and microphysical (particle size and ice water path) properties taking into account critical vertical

Full access
Bart De Paepe and Steven Dewitte

often appeared as a gap on the current aerosol retrievals, since most aerosol retrieval algorithms use the solar channels that are not suited to work over bright reflecting surfaces, such as the desert. Algorithms that use other parts of the spectrum, such as the ultraviolet ( Hsu et al. 2004 ), help to overcome these problems. In addition to the spectral information, there are algorithms that use angular information to retrieve the aerosol optical properties. The Multiangle Imaging

Full access
David Antoine, André Morel, Edouard Leymarie, Amel Houyou, Bernard Gentili, Stéphane Victori, Jean-Pierre Buis, Nicolas Buis, Sylvain Meunier, Marius Canini, Didier Crozel, Bertrand Fougnie, and Patrice Henry

which photons are simply diverted from their initial direction of propagation. These phenomena are described by coefficients that belong to the “inherent” optical properties (IOPs; Preisendorfer 1961 ). The way these processes alter the radiant field is described by the radiative transfer equation (RTE) ( Mobley 1994 ). To describe the radiant field inside a scattering/absorbing medium, like a water body, the spectral radiance ( L ) is the fundamental radiometric quantity (units: W m −2 sr −1 nm

Full access
K. M. Markowicz, P. J. Flatau, A. E. Kardas, J. Remiszewska, K. Stelmaszczyk, and L. Woeste

1. Introduction The role of atmospheric aerosols in modifying the radiation budget of the earth–atmosphere climate system is being increasingly understood and recognized ( Hansen et al. 1997 ; Haywood et al. 1999 ; Ramanathan et al. 2001 ). There are still large uncertainties of the aerosol radiative forcing on regional scales ( Houghton et al. 2001 ) because of the lack of sufficient knowledge of aerosols’ optical, physical, and chemical properties and their large spatial and temporal

Full access