• Chaboureau, J-P., J-P. Cammas, P. Mascart, J-P. Pinty, C. Claud, R. Roca, and J-J. Morcrette, 2000: Evaluation of a cloud system life-cycle simulated by Meso-NH during FASTEX using METEOSAT radiances and TOVS-3I cloud retrievals. Quart. J. Roy. Meteor. Soc, 126 , 17351750.

    • Search Google Scholar
    • Export Citation
  • Chevallier, F., and J-J. Morcrette, 2000: Comparison of model fluxes with surface and top-of-the-atmosphere observations. Mon. Wea. Rev, 128 , 38393852.

    • Search Google Scholar
    • Export Citation
  • Chevallier, F., P. Bauer, G. Kelly, C. Jakob, and T. McNally, 2001: Model clouds over oceans as seen from space: Comparison with HIRS/2 and MSU radiances. J. Climate, 14 , 42164229.

    • Search Google Scholar
    • Export Citation
  • Courtier, P., J-N. Thépaut, and A. Hollingsworth, 1994: A strategy, for operational implementation of 4D-Var, using an incremental approach. Quart. J. Roy. Meteor. Soc, 120 , 13671388.

    • Search Google Scholar
    • Export Citation
  • Ebert, E. E., and J. A. Curry, 1992: A parameterization of ice optical properties for climate models. J. Geophys. Res, 97D , 38313836.

    • Search Google Scholar
    • Export Citation
  • Eyre, J. R., 1991: A fast radiative transfer model for satellite sounding systems. ECMWF Tech. Memo. 176, 28 pp.

  • Fouquart, Y., and B. Bonnel, 1980: Computation of solar heating of the earth's atmosphere: A new parameterization. Beitr. Phys. Atmos, 53 , 3562.

    • Search Google Scholar
    • Export Citation
  • Gregory, D., J-J. Morcrette, C. Jakob, A. C. M. Beljaars, and T. Stockdale, 2000: Revision of convection, radiation and cloud schemes in the ECMWF Integrated Forecasting System. Quart. J. Roy. Meteor. Soc, 126 , 16851710.

    • Search Google Scholar
    • Export Citation
  • Hortal, M., 1999: The development and testing of a new two-time-level semi-Lagrangian scheme (SETTLS) in the ECMWF forecast model. ECMWF Tech. Memo. 292, 17 pp. [Available from ECMWF, Shinfield Park, Reading, Berkshire RG2 9AX, United Kingdom.].

    • Search Google Scholar
    • Export Citation
  • Jakob, C., 1999: Cloud cover in the ECMWF reanalysis. J. Climate, 12 , 947959.

  • Jakob, C., 2000: The representation of cloud cover in atmospheric general circulation models. Ph.D. thesis, Ludwig-Maximilians-Universität, Munich, Germany, 193 pp.

    • Search Google Scholar
    • Export Citation
  • Jakob, C., and S. A. Klein, 2000: A parametrization of the effects of cloud and precipitation overlap for use in general-circulation models. Quart. J. Roy. Meteor. Soc, 126 , 25252544.

    • Search Google Scholar
    • Export Citation
  • Jakob, C., and and Coauthors, 2000: The IFS cycle CY21r4 made operational in October 1999. ECMWF Newsletter, Vol. 87, 2–9.

  • Janisková, M., 2001: Preparatory studies for the use of observations from the earth radiation mission in numerical weather prediction. Report from ESA Contract 13151/98/NL/GD, 79 pp. [Available from ECMWF, Shinfield Park, Reading, Berkshire RG2 9AX, United Kingdom.].

    • Search Google Scholar
    • Export Citation
  • Joyce, R., J. Janowiak, and G. Huffman, 2001: Latitudinally and seasonally dependent zenith-angle corrections for geostationary satellite IR brightness temperatures. J. Appl. Meteor, 40 , 689703.

    • Search Google Scholar
    • Export Citation
  • Laprise, R., 1992: The resolution of global spectral models. Bull. Amer. Meteor. Soc, 73 , 14531454.

  • Lazzara, M. A., and and Coauthors, 1999: The Man computer Interactive Data Access System (McIDAS): 25 Years of Interactive Processing. Bull. Amer. Meteor. Soc, 80 , 271284.

    • Search Google Scholar
    • Export Citation
  • Mlawer, E. J., S. J. Taubman, P. D. Brown, M. J. Iacono, and S. A. Clough, 1997: Radiative transfer for inhomogeneous atmospheres: RRTM, a validated correlated-k model for the longwave. J. Geophys. Res, 102 , 1666316682.

    • Search Google Scholar
    • Export Citation
  • Morcrette, J-J., 1991: Evaluation of model-generated cloudiness: Satellite observed and model-generated diurnal variability and brightness temperature. Mon. Wea. Rev, 119 , 12051224.

    • Search Google Scholar
    • Export Citation
  • Morcrette, J-J., 2001: Assessment of the ECMWF model cloudiness and surface radiation fields at the ARM-SGP site. ECMWF Tech. Memo. 327. [Available from ECMWF, Shinfield Park, Reading, Berkshire RG2 9AX, United Kingdom.].

    • Search Google Scholar
    • Export Citation
  • Munro, R., G. Kelly, and R. Saunders, 2000: Assimilation of Meteosat radiance data within the 4DVAR system at ECMWF. EUMETSAT/ECMWF Fellowship Programme Rep. 8, 41 pp. [Available from ECMWF, Shinfield Park, Reading, Berkshire RG2 9AX, United Kingdom.].

    • Search Google Scholar
    • Export Citation
  • Pielke, R. A., 1991: A recommended specific definition of “resolution.”. Bull. Amer. Meteor. Soc, 72 , 1914.

  • Räisänen, P., 1998: Effective longwave cloud fraction and maximum-random overlap clouds—A problem and a solution. Mon. Wea. Rev, 126 , 33363340.

    • Search Google Scholar
    • Export Citation
  • Rizzi, R., 1994: Raw HIRS/2 radiances and model simulations in the presence of clouds. ECMWF Tech. Memo. 73, 29 pp. [Available from ECMWF, Shinfield Park, Reading, Berkshire RG2 9AX, United Kingdom.].

    • Search Google Scholar
    • Export Citation
  • Roca, R., L. Picon, M. Desbois, H. Le Treut, and J-J. Morcrette, 1997: Direct comparison of Meteosat water vapor channel data and general circulation model results. Geophys. Res. Lett, 24 , 147150.

    • Search Google Scholar
    • Export Citation
  • Rohn, M., G. Kelly, and R. W. Saunders, 2001: Impact of new cloud motion wind product from Meteosat on NWP analyses and forecasts. Mon. Wea. Rev, 129 , 23922403.

    • Search Google Scholar
    • Export Citation
  • Rossow, W. B., and R. A. Schiffer, 1983: The International Satellite Cloud Climatology Project (ISCCP): The first project of the World Climate Research Program. Bull. Amer. Meteor. Soc, 64 , 779784.

    • Search Google Scholar
    • Export Citation
  • Saunders, R., M. Matricardi, and P. Brunel, 1999: An improved fast radiative transfer model for assimilation of satellite radiance observations. Quart. J. Roy. Meteor. Soc, 125 , 14071425.

    • Search Google Scholar
    • Export Citation
  • Schmetz, J., K. Holmlund, J. Hoffman, B. Strauss, B. Mason, V. Gaertner, A. Koch, and L. van de Berg, 1993: Operational cloud-motion winds from Meteosat infrared images. J. Appl. Meteor, 32 , 12061225.

    • Search Google Scholar
    • Export Citation
  • Sherlock, V. J., 1999: ISEM-6: Infrared Surface Emissivity Model for RTTOV-6. Forecasting Research Tech. Rep. FR-299, Met Office, 17 pp. [Available from Met Office, London Road, Bracknell RG12 2SZ, United Kingdom.].

    • Search Google Scholar
    • Export Citation
  • Smith, E. A., and L. Shi, 1992: Surface forcing of the infrared cooling profile over the Tibetan plateau. Part I: Influence of relative longwave radiative heating at high altitude. J. Atmos. Sci, 49 , 805822.

    • Search Google Scholar
    • Export Citation
  • Soden, B., and F. Bretherton, 1994: Upper-tropospheric relative humidity from the GOES 6.7 μm channel—Method and climatology for July 1987. J. Geophys. Res, 99 , 11871210.

    • Search Google Scholar
    • Export Citation
  • Tiedtke, M., 1993: Representation of clouds in large-scale models. Mon. Wea. Rev, 121 , 30403061.

  • van de Berg, L. C. J., J. Schmetz, and J. Whitlock, 1995: On the calibration of the Meteosat water vapor channel. J. Geophys. Res, 100 , 2106921076.

    • Search Google Scholar
    • Export Citation
  • van den Hurk, B. J. J. M., P. Viterbo, A. C. M. Beljaars, and A. K. Betts, 2000: Offline validation of the ERA40 surface scheme. ECMWF Tech. Memo. 295, 42 pp. [Available from ECMWF, Shinfield Park, Reading, Berkshire RG2 9AX, United Kingdom.].

    • Search Google Scholar
    • Export Citation
  • Velden, C. S., C. M. Hayden, W. P. Menzel, J. L. Franklin, and J. S. Lynch, 1992: The impact of satellite-derived winds on numerical hurricane track forecasting. Wea. Forecasting, 7 , 107118.

    • Search Google Scholar
    • Export Citation
  • Velden, C. S., S. J. Niemann, W. P. Menzel, and S. T. Wanzong, 1997: Upper-tropospheric winds derived from geostationary satellite water vapor observations. Bull. Amer. Meteor. Soc, 78 , 173195.

    • Search Google Scholar
    • Export Citation
  • Washington, W. M., and D. L. Williamson, 1977: A description of the NCAR GCM. Methods in Computational Physics, J. Chang, Ed., Vol. 17, Academic Press, 111–172.

    • Search Google Scholar
    • Export Citation
  • Wylie, D. P., W. P. Menzel, H. M. Woolf, and K. I. Strabala, 1994: Four years of global cirrus cloud statistics using HIRS. J. Climate, 7 , 19721986.

    • Search Google Scholar
    • Export Citation
  • Yu, W., L. Garand, and A. P. Dastoor, 1997: Evaluation of model clouds and radiation at 100 km scale using GOES data. Tellus, 49A , 246262.

    • Search Google Scholar
    • Export Citation
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Model Clouds as Seen from Space: Comparison with Geostationary Imagery in the 11-μm Window Channel

F. ChevallierEuropean Centre for Medium-Range Weather Forecasts, Reading, Berkshire, United Kingdom

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G. KellyEuropean Centre for Medium-Range Weather Forecasts, Reading, Berkshire, United Kingdom

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Abstract

A monitoring of the European Centre for Medium-Range Weather Forecasts (ECMWF) model with the Meteosat infrared window channel during December 2000 is presented. The Meteosat images are simulated every 3 h during the 31 days of the month from the model fields, at a resolution of 35 km. The study of both the spatial and the temporal variabilities of the model cloudiness is based on forecasts, from 3 to 48 h, as well as on analyses. Despite a reduced cloud forcing in the model, the variations of the extratropical cyclones are shown to be well represented in the short-range (up to 1 day) forecasts. The intertropical convergence zone (ITCZ) is well located but the representation of its temporal variations significantly differs from the observations, in particular over land. The variability of the Meteosat brightness temperature time series usually differs by more than 10% from one model grid point to another, whereas the structures described by the model have scales of about three to four grid points at least.

This work prepares the routine monitoring of the ECMWF analysis and forecast system with the raw images from Meteosat, soon to be replaced by the Meteosat Second Generation imager/sounder, and is an important step toward the assimilation of cloud-affected satellite radiances.

Corresponding author address: F. Chevallier, ECMWF, Shinfield Park, Reading, Berkshire RG29AX, United Kingdom. Email: f.chevallier@ecmwf.int

Abstract

A monitoring of the European Centre for Medium-Range Weather Forecasts (ECMWF) model with the Meteosat infrared window channel during December 2000 is presented. The Meteosat images are simulated every 3 h during the 31 days of the month from the model fields, at a resolution of 35 km. The study of both the spatial and the temporal variabilities of the model cloudiness is based on forecasts, from 3 to 48 h, as well as on analyses. Despite a reduced cloud forcing in the model, the variations of the extratropical cyclones are shown to be well represented in the short-range (up to 1 day) forecasts. The intertropical convergence zone (ITCZ) is well located but the representation of its temporal variations significantly differs from the observations, in particular over land. The variability of the Meteosat brightness temperature time series usually differs by more than 10% from one model grid point to another, whereas the structures described by the model have scales of about three to four grid points at least.

This work prepares the routine monitoring of the ECMWF analysis and forecast system with the raw images from Meteosat, soon to be replaced by the Meteosat Second Generation imager/sounder, and is an important step toward the assimilation of cloud-affected satellite radiances.

Corresponding author address: F. Chevallier, ECMWF, Shinfield Park, Reading, Berkshire RG29AX, United Kingdom. Email: f.chevallier@ecmwf.int

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