Search Results

You are looking at 1 - 10 of 1,496 items for :

  • Optical properties x
  • Journal of Applied Meteorology and Climatology x
  • All content x
Clear All
Ping Yang, Zhibo Zhang, George W. Kattawar, Stephen G. Warren, Bryan A. Baum, Hung-Lung Huang, Yong X. Hu, David Winker, and Jean Iaquinta

parameterization of the bulk radiative properties of ice clouds, which is a necessary component of the radiative transfer schemes used in climate models, it is important to learn more about the optical properties of highly complex, nonspherical ice particles. The optical properties are determined fundamentally by the ice habits, particle size distributions, and refractive indices. Furthermore, modeling the optical properties of complex ice particles is also an interesting but challenging research topic in the

Full access
Krzysztof M. Markowicz and Marcin L. Witek

forcing for optical depths between 2 and 3 ( Jensen et al. 1994 ; Meerkötter et al. 1999 ) and of nearly 3 ( Fu and Liou 1993 ). These values suggest that some observed contrail-induced cirrus clouds may already exert the strongest possible warming. Here we address some of the existing uncertainties by performing a detailed sensitivity study of contrail radiative-forcing computations on various parameters, primarily on the parameterization of ice-crystal shape and optical properties. Radiative

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
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
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
S. R. Pal, A. I. Carswell, I. Gordon, and A. Fong

2388 JOURNAL OF APPLIED METEOROLOGY VOLUME34Lidar-Derived Cloud Optical Properties Obtained during the ECLIPS Program S. R. PAL, A. I. CARSWELL, I. GORDON, AND A. FONGInstitute for Space and Terrestrial ~cience and Department of Physics and Astronomy, York University, North York, Ontario, Canada(Manuscript received 24 October 1994, in final form 10 May 1995)ABSTRACT This paper presents the statistical properties of

Full access
U. C. Dumka, K. Krishna Moorthy, S. K. Satheesh, Ram Sagar, and P. Pant

, thereby leading to increased AODs in the AN period. Aerosols over the Indian subcontinent may have implications for cloud microphysical properties and the radiation budget. 5. Conclusions Multiyear measurements of spectral aerosol optical depths (AODs) made at Manora Peak in the central Himalayas have revealed the following. The AODs at 0.5 μ m were very low (≤0.1) in winter and increased rather steeply to reach high values (∼0.5) in summer. The monthly mean AODs vary significantly (by more than a

Full access
T. Cherubini, S. Businger, R. Lyman, and M. Chun

1. Introduction Atmospheric turbulence is a key challenge in ground-based astronomy because it dramatically impacts the angular resolution of a telescope. Small-scale temperature and moisture fluctuations in the atmosphere result in fluctuations of the refractive index. The wave front of radiation traveling through the atmosphere changes as it encounters inhomogeneities in the refractive index, degrading optical image quality. The intensity of the turbulent fluctuations of the atmospheric

Full access
Guy Potvin, Denis Dion, Jacques Claverie, Paul A. Frederickson, Kenneth L. Davidson, and J. Luc Forand

1. Introduction Atmospheric turbulence can significantly affect the performance of electro-optical imaging systems to detect and identify objects, being responsible for scintillation, blurring, and image wandering. The theory, in the scientific literature, relates the turbulence effects to the optical refractive index structure parameter C 2 n , which characterizes the rapid fluctuation of the index of refraction ( Beland 1993 ). For predicting turbulence effects on an imaging system, it would

Full access
Philippe Dubuisson, Vincent Giraud, Jacques Pelon, Bertrand Cadet, and Ping Yang

1. Introduction Ice clouds play an important role in the earth’s radiation budget and climate ( Liou 1986 ). Accurate information of their optical properties is critical to assessing the climate effects and feedback associated with these clouds ( Stephens et al. 1990 ). Reflected solar radiation and emitted longwave radiation under cirrus cloudy conditions depend strongly upon the complex microphysical properties of these clouds ( Mitchell et al. 1996 ; Fu et al. 1998 , 1999 ; Chepfer et al

Full access