Search Results
distributions have been a major impediment to understanding how the Tropics interact with other parts of the globe, including the remote response to tropical El Niño–Southern Oscillation (ENSO) variability on interannual time scales, and the possible global influence of the Madden–Julian oscillation (MJO) and monsoons on intraseasonal time scales. A global atmospheric analysis capable of capturing the observed tropical rainfall variability accompanied by physically consistent estimates of wind, temperature
distributions have been a major impediment to understanding how the Tropics interact with other parts of the globe, including the remote response to tropical El Niño–Southern Oscillation (ENSO) variability on interannual time scales, and the possible global influence of the Madden–Julian oscillation (MJO) and monsoons on intraseasonal time scales. A global atmospheric analysis capable of capturing the observed tropical rainfall variability accompanied by physically consistent estimates of wind, temperature
based on satellite data, a more global, continuous, and consistent observation of cloud and precipitation properties represents a fundamental requirement of NWP. Polar orbiting satellites provide poor temporal sampling (6-h in the worst case in the Tropics) relative to the time scales of precipitation development. Geostationary satellite infrared (IR) measurements are hampered by the poor relationships between cloud-top temperatures and the underlying cloud and precipitation physics. Microwave (MW
based on satellite data, a more global, continuous, and consistent observation of cloud and precipitation properties represents a fundamental requirement of NWP. Polar orbiting satellites provide poor temporal sampling (6-h in the worst case in the Tropics) relative to the time scales of precipitation development. Geostationary satellite infrared (IR) measurements are hampered by the poor relationships between cloud-top temperatures and the underlying cloud and precipitation physics. Microwave (MW
overprediction of low cloud fraction in winter high latitudes by both the climate run and the analysis, and the somewhat more complicated comparison between climate run, analysis, and data in the Tropics. The overall poor performance of the model both in climate mode and even more so in assimilation mode was the motivation for our efforts to assimilate observational cloud fraction data into the GEOS-4 DAS. b. Overview and design of the cloud parameter estimation system From the beginning we attempted to
overprediction of low cloud fraction in winter high latitudes by both the climate run and the analysis, and the somewhat more complicated comparison between climate run, analysis, and data in the Tropics. The overall poor performance of the model both in climate mode and even more so in assimilation mode was the motivation for our efforts to assimilate observational cloud fraction data into the GEOS-4 DAS. b. Overview and design of the cloud parameter estimation system From the beginning we attempted to
forecast models. Mon. Wea. Rev. , 130 , 1882 – 1897 . Guo , Y-R. , Y-H. Kuo , J. Dudhia , D. Parsons , and C. Rocken , 2000 : Four-dimensional variational data assimilation of heterogeneous mesoscale observations for a strong convective case. Mon. Wea. Rev. , 128 , 619 – 643 . Heckley , W. A. , G. Kelly , and M. Tiedtke , 1990 : On the use of satellite-derived heating rates for data assimilation within the tropics. Mon. Wea. Rev. , 118 , 1743 – 1757 . Hollingsworth
forecast models. Mon. Wea. Rev. , 130 , 1882 – 1897 . Guo , Y-R. , Y-H. Kuo , J. Dudhia , D. Parsons , and C. Rocken , 2000 : Four-dimensional variational data assimilation of heterogeneous mesoscale observations for a strong convective case. Mon. Wea. Rev. , 128 , 619 – 643 . Heckley , W. A. , G. Kelly , and M. Tiedtke , 1990 : On the use of satellite-derived heating rates for data assimilation within the tropics. Mon. Wea. Rev. , 118 , 1743 – 1757 . Hollingsworth
environmental conditions, their microphysical properties could be quite different from those in the Tropics. Thus, it would appear that separate HDs and SDs should be constructed for midlatitude cirrus clouds for future remote sensing study. c. Single-scattering properties for cirrus clouds Following Yang et al. (2000 , 2003 , 2005 ) and Zhang et al. (2004) , we have considered seven ice crystal habits including droxtals, spheroids, plates, solid and hollow columns, bullet rosettes, and aggregates. For
environmental conditions, their microphysical properties could be quite different from those in the Tropics. Thus, it would appear that separate HDs and SDs should be constructed for midlatitude cirrus clouds for future remote sensing study. c. Single-scattering properties for cirrus clouds Following Yang et al. (2000 , 2003 , 2005 ) and Zhang et al. (2004) , we have considered seven ice crystal habits including droxtals, spheroids, plates, solid and hollow columns, bullet rosettes, and aggregates. For
radiative transfer model. Appl. Opt. , 43 , 3103 – 3109 . Krishnamurti , T. N. , J. Xue , H. S. Bedi , K. Ingles , and D. Oosterhof , 1991 : Physical initialization for numerical weather prediction over the tropics. Tellus , 43 , 53 – 81 . Kuo , Y-H. , X. Zou , and Y. R. Guo , 1996 : Variational assimilation of precipitable water using a nonhydrostatic mesoscale adjoint model. Part I: Moisture retrieval and sensitivity experiments. Mon. Wea. Rev. , 124 , 122 – 147
radiative transfer model. Appl. Opt. , 43 , 3103 – 3109 . Krishnamurti , T. N. , J. Xue , H. S. Bedi , K. Ingles , and D. Oosterhof , 1991 : Physical initialization for numerical weather prediction over the tropics. Tellus , 43 , 53 – 81 . Kuo , Y-H. , X. Zou , and Y. R. Guo , 1996 : Variational assimilation of precipitable water using a nonhydrostatic mesoscale adjoint model. Part I: Moisture retrieval and sensitivity experiments. Mon. Wea. Rev. , 124 , 122 – 147
readily be integrated on geostationary satellites such as Geostationary Operational Environmental Satellites (GOES; Solman et al. 1998 ). In particular, the 380-GHz water vapor resonance and the 425-GHz oxygen resonance were selected for their abilities to sense individual convective cells larger than ∼10 km, and the 183-GHz water vapor band was selected because it can sense to the surface except in the Tropics. For simplicity the sensitivity of all channels is assumed to be 0.2-K rms, although for
readily be integrated on geostationary satellites such as Geostationary Operational Environmental Satellites (GOES; Solman et al. 1998 ). In particular, the 380-GHz water vapor resonance and the 425-GHz oxygen resonance were selected for their abilities to sense individual convective cells larger than ∼10 km, and the 183-GHz water vapor band was selected because it can sense to the surface except in the Tropics. For simplicity the sensitivity of all channels is assumed to be 0.2-K rms, although for
Analysis, Reading, United Kingdom, European Centre for Medium-Range Weather Forecasts, 33–47 . Trémolet , Y. , 2005 : Accounting for an imperfect model in 4D-Var. ECMWF Tech. Memo. 477, 20 pp . Tsuyuki , T. , 1997 : Variational data assimilation in the Tropics using precipitation data. Part III: Assimilation of SSM/I precipitation rates. Mon. Wea. Rev. , 125 , 1447 – 1464 . Tsuyuki , T. , K. Koizumi , and Y. Ishikawa , 2002 : The JMA mesoscale 4D-Var system and assimilation of
Analysis, Reading, United Kingdom, European Centre for Medium-Range Weather Forecasts, 33–47 . Trémolet , Y. , 2005 : Accounting for an imperfect model in 4D-Var. ECMWF Tech. Memo. 477, 20 pp . Tsuyuki , T. , 1997 : Variational data assimilation in the Tropics using precipitation data. Part III: Assimilation of SSM/I precipitation rates. Mon. Wea. Rev. , 125 , 1447 – 1464 . Tsuyuki , T. , K. Koizumi , and Y. Ishikawa , 2002 : The JMA mesoscale 4D-Var system and assimilation of
