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precipitation. The issue is how to use this information to improve the initialization of clouds and precipitation in models. Since clouds and precipitation often occur in sensitive regions for forecast impacts, such improvements are likely necessary for continuing to acquire significant gains in weather forecasting. To accelerate progress in the field, the Joint Center for Satellite Data Assimilation (JCSDA), a joint activity of the National Oceanic and Atmospheric Administration (NOAA), National
precipitation. The issue is how to use this information to improve the initialization of clouds and precipitation in models. Since clouds and precipitation often occur in sensitive regions for forecast impacts, such improvements are likely necessary for continuing to acquire significant gains in weather forecasting. To accelerate progress in the field, the Joint Center for Satellite Data Assimilation (JCSDA), a joint activity of the National Oceanic and Atmospheric Administration (NOAA), National
. Staelin , 2006 : Comparison of AMSU millimeter-wave satellite observations, MM5/TBSCAT predicted radiances, and electromagnetic models for hydrometeors. IEEE Trans. Geosci. Remote Sens. , 44 , 2667 – 2678 . Tao , W-K. , and J. Simpson , 1993 : Goddard cumulus ensemble model. Part I: Model description. Terr. Atmos. Oceanic Sci. , 4 , 35 – 72 . Tassa , A. , S. D. Michele , A. Mugnai , F. S. Marzano , P. Bauer , J. Pedro , and J. P. V. P. Baptista , 2006 : Modeling
. Staelin , 2006 : Comparison of AMSU millimeter-wave satellite observations, MM5/TBSCAT predicted radiances, and electromagnetic models for hydrometeors. IEEE Trans. Geosci. Remote Sens. , 44 , 2667 – 2678 . Tao , W-K. , and J. Simpson , 1993 : Goddard cumulus ensemble model. Part I: Model description. Terr. Atmos. Oceanic Sci. , 4 , 35 – 72 . Tassa , A. , S. D. Michele , A. Mugnai , F. S. Marzano , P. Bauer , J. Pedro , and J. P. V. P. Baptista , 2006 : Modeling
coverage and its relationship to wind speed, viewing angle, and microwave frequency ( Hollinger 1971 ; Wilheit 1979 ). A sea surface emissivity model developed by the Met Office, United Kingdom ( English and Takashima 1998 ), was also tested in the operational environment. This model was initially developed based on geometrical optics, where the large-scale ocean waves are modeled using tilting surface facets whose scattering coefficients are proportional to the number of surface facets with a sloping
coverage and its relationship to wind speed, viewing angle, and microwave frequency ( Hollinger 1971 ; Wilheit 1979 ). A sea surface emissivity model developed by the Met Office, United Kingdom ( English and Takashima 1998 ), was also tested in the operational environment. This model was initially developed based on geometrical optics, where the large-scale ocean waves are modeled using tilting surface facets whose scattering coefficients are proportional to the number of surface facets with a sloping
. Climatol. , 45 , 20 – 41 . Liu , G. , and J. A. Curry , 1996 : Large-scale cloud features during January 1993 in the North Atlantic Ocean as determined from SSM/I and SSM/T2 observations. J. Geophys. Res. , 101 , 7019 – 7032 . Mace , G. G. , C. Jakob , and K. P. Moran , 1998 : Validation of hydrometeor occurrence predicted by the ECMWF model using millimeter wave radar data. Geophys. Res. Lett. , 25 , 1645 – 1648 . Masunaga , H. , and C. D. Kummerow , 2005 : Combined
. Climatol. , 45 , 20 – 41 . Liu , G. , and J. A. Curry , 1996 : Large-scale cloud features during January 1993 in the North Atlantic Ocean as determined from SSM/I and SSM/T2 observations. J. Geophys. Res. , 101 , 7019 – 7032 . Mace , G. G. , C. Jakob , and K. P. Moran , 1998 : Validation of hydrometeor occurrence predicted by the ECMWF model using millimeter wave radar data. Geophys. Res. Lett. , 25 , 1645 – 1648 . Masunaga , H. , and C. D. Kummerow , 2005 : Combined
global NWP model 6-h forecasts at roughly 40-km horizontal resolution, chosen for their representativeness of different precipitation regimes. Two separate sets of profiles were used: 24 000 profiles were taken from the Atlantic Ocean in July 2004, hereafter referred to as the summer profiles, and 10 000 profiles were taken from the Atlantic Ocean in January 2004, referred to as the winter profiles; see Di Michele and Bauer (2006) for details. All profiles are composed of 60 vertical atmospheric
global NWP model 6-h forecasts at roughly 40-km horizontal resolution, chosen for their representativeness of different precipitation regimes. Two separate sets of profiles were used: 24 000 profiles were taken from the Atlantic Ocean in July 2004, hereafter referred to as the summer profiles, and 10 000 profiles were taken from the Atlantic Ocean in January 2004, referred to as the winter profiles; see Di Michele and Bauer (2006) for details. All profiles are composed of 60 vertical atmospheric
: Model rain and clouds over ocean: Comparison with SSM/I observations. Mon. Wea. Rev. , 131 , 1240 – 1255 . English , S. J. , and T. J. Takashima , 1998 : A fast generic millimeter-wave emissivity model. Proc. SPIE , 3503 , 288 – 300 . Evans , K. F. , 2007 : SHDOMPPDA: A radiative transfer model for cloudy sky data assimilation. J. Atmos. Sci. , 64 , 3854 – 3864 . Greenwald , T. , R. Bennartz , C. O’Dell , and A. Heidinger , 2005 : Fast computation of microwave
: Model rain and clouds over ocean: Comparison with SSM/I observations. Mon. Wea. Rev. , 131 , 1240 – 1255 . English , S. J. , and T. J. Takashima , 1998 : A fast generic millimeter-wave emissivity model. Proc. SPIE , 3503 , 288 – 300 . Evans , K. F. , 2007 : SHDOMPPDA: A radiative transfer model for cloudy sky data assimilation. J. Atmos. Sci. , 64 , 3854 – 3864 . Greenwald , T. , R. Bennartz , C. O’Dell , and A. Heidinger , 2005 : Fast computation of microwave
size and habit factors, have been inferred by a χ 2 -minimization program involving differences between the modeled and measured AIRS BT spectra. Moreover, we compare these inferred values to the independently derived cirrus optical depth and ice crystal size from collocated and coincident ground-based Department of Energy’s (DOE’s) Atmospheric Radiation Measurement (ARM) program millimeter-wave cloud radar (MMCR) retrievals. We have also carried out numerical experiments to study the sensitivity
size and habit factors, have been inferred by a χ 2 -minimization program involving differences between the modeled and measured AIRS BT spectra. Moreover, we compare these inferred values to the independently derived cirrus optical depth and ice crystal size from collocated and coincident ground-based Department of Energy’s (DOE’s) Atmospheric Radiation Measurement (ARM) program millimeter-wave cloud radar (MMCR) retrievals. We have also carried out numerical experiments to study the sensitivity
1. Introduction Over the past 40 yr, our ability to forecast the weather and to simulate the climate of our planet with numerical models has strongly benefited from the growing understanding of the ocean–atmosphere system and from the constant progress in computer technology. Whether a given numerical model is able to properly forecast the state of the atmosphere up to 10 days or to produce realistic climatic simulations on monthly time scales strongly depends on its ability to represent the
1. Introduction Over the past 40 yr, our ability to forecast the weather and to simulate the climate of our planet with numerical models has strongly benefited from the growing understanding of the ocean–atmosphere system and from the constant progress in computer technology. Whether a given numerical model is able to properly forecast the state of the atmosphere up to 10 days or to produce realistic climatic simulations on monthly time scales strongly depends on its ability to represent the
