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Kuan-Man Xu

cloud overlap assumption for each ECMWF grid that is divided into a number of subgrid cells or subcolumns. The Fu–Liou radiation model ( Fu and Liou 1992 ) is used to compute the cloud optical depth and radiative fluxes for each subcolumn. A threshold on cloud optical depth is used to determine the cloud-top height while selection criteria for DC cloud objects are used to select subcolumns for producing the pdfs of cloud physical properties. These steps are discussed in detail below. First, each

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Zhian Sun and Lawrie Rikus

climatology may be considered adequate, real-time cloud fields are more difficult to characterize and validate, particularly if cloud optical properties are involved. Nevertheless it has been shown that the scheme is capable of providing useful and timely information about the operational medium-range prediction model and has also been used as a validation tool for the development of a modified diagnostic cloud scheme and various cloud optical property schemes implemented into the GASP model, leading to

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Jean-Jacques Morcrette

APRIL 1990 JEAN-JACQUES MORCRETTE 847Impact of Changes to the Radiation Transfer Parameterizations Plus Cloud Optical. Properties in the ECMWF Model JEAN-JACQUES MORCRETTEEuropean Centre for Medium-Range Weather Forecasts, Shinfield Park, Reading, Berkshire, England(Manuscript received 10 July 1989, in final form 18 October 1989) ABSTRACT A new radiation package

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Angela Benedetti and Marta Janisková

properties of liquid water clouds and Fu (1996) for those of ice clouds. For liquid water clouds, the effective radius ( r e ) is derived from the cloud liquid water content following Martin et al. (1994) , with the concentration of cloud condensation nuclei fixed at 50 cm −3 over the oceans and 900 cm −3 over the continents. For ice clouds, the effective size of the particles is a function of temperature following Ou and Liou (1995) . A detailed description of the cloud optical depth

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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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C. J. Grund and E. W. Eloranta

2344 MONTHLY WEATHER REVIEW VOLUM-118The 27-28 October 1986 FIRE IFO Cirrus Case Study: Cloud Optical Properties Determined by High Spectral Resolution Lidar C. J. GRUND AND E. W. ELORANTAUniversity of Wisconsin-Madison, Department of Meteorology, Madison, WisconsinManuscript received 17 February 1989, in final form 12 June 1990) ABSTRACT During

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Jui-Lin F. Li, Martin Köhler, John D. Farrara, and C. R. Mechoso

stratocumulus cloud optical thicknesses than those estimated using ISCCP-D2 data (see Figs. 4e and 4f ; Rossow et al. 1996 ). In the model that produced Fig. 2 , stratocumulus cloud optical thickness is simply proportional to cloud depth. It has been recognized, however, that cloud properties such as the vertical integral of liquid water path (LWP) and the cloud particle size distribution can have large impacts on PBL cloud radiative properties ( Gultepe and Isaac 1997 ). In most AGCMs, the determination

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Frédérique Chéruy and Filipe Aires

, the DX version of the ISCCP data will be used: it provides cloud information [radiatively determined cloud-top pressure (CTP) and optical thicknes] at a satellite resolution level: about 10-km pixel size at these latitudes, with a horizontal sampling rate of 25–30 km. In this paper, only cloud properties retrieved from the IR and VIS radiances measured by the radiometer aboard the geostationary Meteosat are used. In section 2 , a clustering algorithm is designed to find the most important

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Laurent Sauvage, Pierre H. Flamant, Hélène Chepfer, Gérard Brogniez, Vincent Trouillet, Jacques Pelon, and Franck Albers

physical and optical properties to be used in models. In order to illustrate the need in this area, it has been shown that the shape and size distribution of crystals and their orientation in space modify to a large extent the scattering properties of cirrus clouds ( Takano and Liou 1989 ; Brogniez et al. 1992 ) and, consequently, their radiative properties. Recently, it has become an issue to document cirrus clouds in order to derive their physical and optical properties that are needed to

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L. A. T. Machado and W. B. Rossow

~sures andmuch higher optical thicknesses, associated with deep convection, and one with higher cloud-top pressures andlower optical thicknesses, associated with the mesoscale stmtiform anvil clouds. The anvil cloud properties showsome evidence of a further division into opt!c~ally thicker and thinner parts. The average properties of theseclouds vary in a correlated fashion such that a larger horizontal extent of the convective system cloud is accompanied by a lower convective cloud-top pressure, larger

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