Editorial Type:
Article
Article Type:
Research Article

The Surface Downward Longwave Radiation in the ECMWF Forecast System

Jean-Jacques Morcrette ECMWF, Shinfield Park, Reading, Berkshire, United Kingdom

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Print Publication:
15 Jul 2002
DOI:
https://doi.org/10.1175/1520-0442(2002)015<1875:TSDLRI>2.0.CO;2
Page(s):
1875–1892
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Abstract

The surface downward longwave radiation, computed by the European Centre for Medium-Range Weather Forecasts (ECMWF) forecast system used for the ECMWF 40-yr reanalysis, is compared with surface radiation measurements for the April–May 1999 period, available as part of the Baseline Surface Radiation Network (BSRN), Surface Radiation (SURFRAD), and Atmospheric Radiation Measurement (ARM) programs. Emphasis is put on comparisons on a 1-h basis, as this allows discrepancies to be more easily linked to differences between model description and observations of temperature, humidity, and clouds. It is also possible to compare the model and observed temporal variability in the surface radiation fluxes.

Comparisons are first carried out at locations for which the spectral model orography differs from the actual station height. Sensitivity of the model fluxes to various algorithms to correct for this discrepancy is explored. A simple interpolation–extrapolation scheme for pressure, temperature, and specific humidity allows the improvement of model calculations of the longwave surface fluxes in most cases.

Intercomparisons of surface longwave radiation are presented for the various longwave radiation schemes operational since the 15-yr ECMWF Re-Analysis (ERA-15) was performed. The Rapid Radiation Transfer Model of Mlawer et al., now operational at ECMWF, is shown to correct for the major underestimation in clear-sky downward longwave radiation seen in ERA-15.

Sensitivity calculations are also carried out to explore the role of the cloud optical properties, cloud effective particle size, and aerosols in the representation of the surface downward longwave radiation.

Corresponding author address: Dr. Jean-Jacques Morcrette, ECMWF, Shinfield Park, Reading, Berkshire RG2 9AX, United Kingdom. Email: Jean-Jacques.Morcrette@ecmwf.int

Abstract

The surface downward longwave radiation, computed by the European Centre for Medium-Range Weather Forecasts (ECMWF) forecast system used for the ECMWF 40-yr reanalysis, is compared with surface radiation measurements for the April–May 1999 period, available as part of the Baseline Surface Radiation Network (BSRN), Surface Radiation (SURFRAD), and Atmospheric Radiation Measurement (ARM) programs. Emphasis is put on comparisons on a 1-h basis, as this allows discrepancies to be more easily linked to differences between model description and observations of temperature, humidity, and clouds. It is also possible to compare the model and observed temporal variability in the surface radiation fluxes.

Comparisons are first carried out at locations for which the spectral model orography differs from the actual station height. Sensitivity of the model fluxes to various algorithms to correct for this discrepancy is explored. A simple interpolation–extrapolation scheme for pressure, temperature, and specific humidity allows the improvement of model calculations of the longwave surface fluxes in most cases.

Intercomparisons of surface longwave radiation are presented for the various longwave radiation schemes operational since the 15-yr ECMWF Re-Analysis (ERA-15) was performed. The Rapid Radiation Transfer Model of Mlawer et al., now operational at ECMWF, is shown to correct for the major underestimation in clear-sky downward longwave radiation seen in ERA-15.

Sensitivity calculations are also carried out to explore the role of the cloud optical properties, cloud effective particle size, and aerosols in the representation of the surface downward longwave radiation.

Corresponding author address: Dr. Jean-Jacques Morcrette, ECMWF, Shinfield Park, Reading, Berkshire RG2 9AX, United Kingdom. Email: Jean-Jacques.Morcrette@ecmwf.int

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  • Augustine, J. A., J. J. DeLuisi, and C. N. Long, 2000: SURFRAD—A national surface radiation budget network for atmospheric research. Bull. Amer. Meteor. Soc., 81 , 2341–2357.

    • 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 , 3839–3852.

    • Search Google Scholar
    • Export Citation

  • Darnell, W. L., S. K. Gupta, and W. F. Staylor, 1983: Downward longwave radiation at the surface from satellite measurements. J. Climate Appl. Meteor., 22 , 1956–1960.

    • Search Google Scholar
    • Export Citation

  • Darnell, W. L., W. F. Staylor, S. K. Gupta, N. A. Ritchey, and A. C. Wilber, 1992: Seasonal variation of surface radiation budget derived from ISCCP-C1 data. J. Geophys. Res., 97 ((D14),) 15741–15760.

    • Search Google Scholar
    • Export Citation

  • Ebert, E. E., and J. A. Curry, 1992: A parameterization for ice optical properties for climate models. J. Geophys. Res., 97 ((D3),) 3831–3836.

    • Search Google Scholar
    • Export Citation

  • Fouquart, Y., 1987: Radiative transfer in climate models. Physically-Based Modelling and Simulation of Climate and Climatic Change, M. E. Schlesinger, Ed., Kluwer Academic, 223–284.

    • Search Google Scholar
    • Export Citation

  • Fu, Q., and K-N. Liou, 1993: Parameterization of the radiative properties of cirrus clouds. J. Atmos. Sci., 50 , 2008–2025.

  • Fu, Q., P. Yang, and W. B. Sun, 1998: An accurate parameterization of the infrared radiative properties of cirrus clouds of climate models. J. Climate, 11 , 2223–2237.

    • Search Google Scholar
    • Export Citation

  • Garratt, J. R., and A. J. Prata, 1996: Downwelling longwave fluxes at continental surfaces—A comparison of observations with GCM simulations and implications for the global land-surface radiation budget. J. Climate, 9 , 646–655.

    • Search Google Scholar
    • Export Citation

  • Garratt, J. R., P. Krummel, and E. Kowalczyk, 1993: The surface energy balance at local and regional scales—A comparison of general circulation model results with observations. J. Climate, 6 , 1090–1109.

    • Search Google Scholar
    • Export Citation

  • Garratt, J. R., A. J. Prata, L. D. Rotstayn, B. J. McAvaney, and S. Cusack, 1998: The surface radiation budget over oceans and continents. J. Climate, 11 , 1951–1968.

    • Search Google Scholar
    • Export Citation

  • Gibson, J. K., P. Kallberg, S. Uppala, A. Nomura, A. Hernandez, and E. Serrano, 1997: The ECMWF Re-Analysis: ERA description. ECMWF Re-Analysis Project Rep. Series, No. 1, 71 pp.

    • 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 , 1685–1710.

    • Search Google Scholar
    • Export Citation

  • Gupta, S. K., A. C. Wilber, W. L. Darnell, and J. T. Suttles, 1993: Longwave surface radiation over the globe from satellite data: An error analysis. Int. J. Remote Sens., 14 , 95–114.

    • Search Google Scholar
    • Export Citation

  • Gupta, S. K., N. A. Ritchey, A. C. Wilber, C. H. Whitlock, G. G. Gibson, and P. W. Stackhouse Jr., 1999: A climatology of surface radiation budget derived from satellite data. J. Climate, 12 , 2691–2710.

    • Search Google Scholar
    • Export Citation

  • Heimo, A., A. Vernez, and P. Wasserfallen, 1993: Baseline Surface Radiation Network (BSRN). Concept and implementation of a BSRN station. WCRP/WMO/TD-579, Geneva, Switzerland, 39 pp.

    • Search Google Scholar
    • Export Citation

  • Hess, M., P. Koepke, and I. Schult, 1998: Optical properties of aerosols and clouds: The software package OPAC. Bull. Amer. Meteor. Soc., 79 , 831–844.

    • Search Google Scholar
    • Export Citation

  • Heymsfield, A. J., and L. J. Donner, 1990: A scheme for parameterizing ice–cloud water content in general circulation models. J. Atmos. Sci., 47 , 1865–1877.

    • Search Google Scholar
    • Export Citation

  • Hortal, M., and A. J. Simmons, 1991: Use of reduced Gaussian grids in spectral models. Mon. Wea. Rev., 119 , 1057–1074.

  • Jakob, C., 1994: The impact of the new cloud scheme on ECMWF's Integrated Forecasting System (IFS). Proc. of ECMWF/GEWEX Workshop on Modelling, Validation and Assimilation of Clouds, Reading, United Kingdom, ECMWF/GEWEX, 277–294.

    • Search Google Scholar
    • Export Citation

  • Jakob, C., and S. A. Klein, 2000: A parameterization of the effects of cloud and precipitation overlap for use in general circulation models. Quart. J. Roy. Meteor. Soc., 126C , 2525–2544.

    • Search Google Scholar
    • Export Citation

  • Koepke, P., M. Hess, I. Schult, and E. P. Shettle, 1997: Global aerosol data set, GADS. Max Planck Institute Rep. 243, 44 pp.

  • Lindner, T. H., and J. Li, 2000: Parameterization of the optical properties for water clouds in the infrared. J. Climate, 13 , 1797–1805.

    • Search Google Scholar
    • Export Citation

  • Mahfouf, J-F., and F. Rabier, 2000: The ECMWF operational implementation of four dimensional variational assimilation. Part II: Experimental results with improved physics. Quart. J. Roy. Meteor. Soc., 126A , 1171–1190.

    • Search Google Scholar
    • Export Citation

  • Martin, G. M., D. W. Johnson, and A. Spice, 1994: The measurement and parameterization of effective radius of droplets in warm stratocumulus. J. Atmos. Sci., 51 , 1823–1842.

    • Search Google Scholar
    • Export Citation

  • Matveev, L. T., 1984: Cloud Dynamics. D. Reidel, 340 pp.

  • 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 ((D14),) 16663–16682.

    • Search Google Scholar
    • Export Citation

  • Morcrette, J-J., 1991: Radiation and cloud radiative properties in the ECMWF operational weather forecast model. J. Geophys. Res., 96 ((D5),) 9121–9132.

    • Search Google Scholar
    • Export Citation

  • Morcrette, J-J., . 2001: The surface downward longwave radiation in the ECMWF forecast system. ECMWF Tech. Memo. 339, 34 pp.

  • Morcrette, J-J., . 2002: Assessment of the ECMWF model cloudiness and surface radiation fields at the ARM-SGP site. Mon. Wea. Rev., 130 , 257–277.

    • Search Google Scholar
    • Export Citation

  • Morcrette, J-J., L. Smith, and Y. Fouquart, 1986: Pressure and temperature dependence of the absorption in longwave radiation parameterizations. Beitr. Phys. Atmos., 59 , 455–469.

    • Search Google Scholar
    • Export Citation

  • Morcrette, J-J., S. A. Clough, E. J. Mlawer, and M. J. Iacono, 1998: Impact of a validated radiative transfer scheme, RRTM, on the ECMWF model climate and 10-day forecasts. ECMWF Tech. Memo. 252, 47 pp.

    • Search Google Scholar
    • Export Citation

  • Ohmura, A., and Coauthors. 1998: Baseline Surface Radiation Network (BSRN/WCRP): New precision radiometry for climate research. Bull. Amer. Meteor. Soc., 79 , 2115–2136.

    • Search Google Scholar
    • Export Citation

  • Ou, S. C., and K-N. Liou, 1995: Ice microphysics and climatic temperature feedback. Atmos. Res., 35 , 127–138.

  • Philipona, R., and Coauthors. 1998: The Baseline Surface Radiation Network pyrgeometer round-robin calibration experiment. J. Atmos. Oceanic Technol., 15 , 687–696.

    • Search Google Scholar
    • Export Citation

  • Rabier, F., J-N. Thepaut, and P. Courtier, 1998: Extended assimilation and forecasts experiments with a four dimensional variational assimilation system. Quart. J. Roy. Meteor. Soc., 124 , 1861–1887.

    • Search Google Scholar
    • Export Citation

  • Rossow, W. B., and Y-C. Zhang, 1995: Calculation of surface and top of the atmosphere radiative fluxes from physical quantities based on ISCCP data sets. Part 2: Validation and first results. J. Geophys. Res., 100 , 1167–1198.

    • Search Google Scholar
    • Export Citation

  • Rothman, L. S., and Coauthors. 1987: The HITRAN database: 1986 edition. Appl. Opt., 26 , 4058–4097.

  • Rothman, L. S., and Coauthors. 1992: The HITRAN database: Editions of 1991 and 1992. J. Quant. Spectrosc. Radiat. Transfer, 48 , 469–507.

    • Search Google Scholar
    • Export Citation

  • Rothman, L. S., and Coauthors. 1996: HITRAN molecular database: Edition '96. J. Quant. Spectrosc. Radiat. Transfer, 60 , 665–710.

  • Savijarvi, H., and P. Raisanen, 1998: Long-wave optical properties of water clouds and rain. Tellus, 50A , 1–11.

  • 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 , 805–822.

    • Search Google Scholar
    • Export Citation

  • Stokes, G. M., and S. E. Schwartz, 1994: The Atmospheric Radiation Measurement (ARM) program: Programmatic background and design of the cloud and radiation testbed. Bull. Amer. Meteor. Soc., 75 , 1201–1221.

    • Search Google Scholar
    • Export Citation

  • Sun, Z., 2001: Reply to comments by G. M. McFarquhar on “Parametrization of effective sizes of cirrus-cloud particles and its verification against observations.”. Quart. J. Roy. Meteor. Soc., 127A , 267–271.

    • Search Google Scholar
    • Export Citation

  • Tanre, D., J-F. Geleyn, and J. Slingo, 1984: First results of the introduction of an advanced aerosol-radiation interaction in the ECMWF low resolution global model. Aerosols and Their Climatic Effects, H. E. Gerber and A. Deepak, Eds., A. Deepak, 133–177.

    • Search Google Scholar
    • Export Citation

  • Temperton, C., M. Hortal, and A. Simmons, 2001: A two-time-level semi-Lagrangian global spectral model. Quart. J. Roy. Meteor. Soc., 127A , 111–127.

    • Search Google Scholar
    • Export Citation

  • Tiedtke, M., 1993: Representation of clouds in large-scale models. Mon. Wea. Rev., 121 , 3040–3061.

  • Tiedtke, M., . 1996: An extension of cloud-radiation parameterization in the ECMWF model: The representation of subgrid-scale variations of optical depth. Mon. Wea. Rev., 124 , 745–750.

    • Search Google Scholar
    • Export Citation

  • Wild, M., 1999: Discrepancies between model-calculated and observed shortwave absorption in equatorial Africa. J. Geophys. Res., 104 ((D22),) 27361–27371.

    • Search Google Scholar
    • Export Citation

  • Wild, M., A. Ohmura, H. Gilgen, and E. Roeckner, 1995a: Regional climate simulation with a high resolution GCM: Surface radiative fluxes. Climate Dyn., 11 , 469–486.

    • Search Google Scholar
    • Export Citation

  • Wild, M., . 1995b: Validation of general circulation model radiative fluxes using surface observations. J. Climate, 8 , 1309–1324.

  • Wild, M., J-J. Morcrette, and A. Slingo, 2001: Evaluation of the downward longwave radiation in general circulation models. J. Climate, 14 , 3227–3239.

    • Search Google Scholar
    • Export Citation

  • WCRP/WMO, 1991: Radiation and Climate: Workshop on the Implementation of the Baseline Surface Radiation Network, WCRP/WMO, WMO Rep. 406, WCRP Rep. 54.

    • Search Google Scholar
    • Export Citation

  • Zhong, W., and J. D. Haigh, 1995: Improved broadband emissivity parameterization for water vapor cooling rate calculations. J. Atmos. Sci., 52 , 124–138.

    • Search Google Scholar
    • Export Citation
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