On the development of a simple downwelling longwave radiation scheme

Abstract This paper addresses the refinement and testing of a simple downwelling longwave radiation model. Oklahoma atmospheric surface-layer instrumentation system (OASIS) radiation data in combination with Oklahoma Mesonet weather data were used to evaluate various techniques for estimating downwelling longwave radiation, for daytime and nighttime as well as clear and cloudy skies. The Brutsaert [Water Resour. Res. 11 (5) (1975) 742] equation, which requires near-surface temperature and vapor pressure data, was chosen for further investigation. A simple regression calibration was performed for Brutsaert’s leading coefficient using hourly data from four OASIS sites. The calibrated equation was applied to five independent OASIS sites and the hourly predictions of downwelling longwave radiation showed good agreement with the measurements. The mean bias error (MBE) ranged between −3.95 and 4.24 W m−2, and the root mean square error (RMSE) was approximately 20 W m−2 in all five cases. Comparisons to a more complex longwave radiation formulation that explicitly considers cloudiness were also quite favorable.

[1]  Martha C. Anderson,et al.  Satellite-based estimates of longwave radiation for agricultural applications. , 2000 .

[2]  Fei Chen,et al.  Validation of the NOAH-OSU land surface model using surface flux measurements in Oklahoma , 2002 .

[3]  K. I. Kondratʹev.  Radiation in the atmosphere , 1969 .

[4]  J. Francis.  A method to derive downwelling longwave fluxes at the Arctic surface from TIROS operational vertical sounder data , 1997 .

[5]  R. L. Elliott,et al.  Configuration decisions for an automated weather station network , 1994 .

[6]  T. M. Crawford,et al.  An Improved Parameterization for Estimating Effective Atmospheric Emissivity for Use in Calculating Daytime Downwelling Longwave Radiation , 1999 .

[7]  P. A. Sheppard,et al.  Long-wave radiation from clear skies , 1964 .

[8]  Ray D. Jackson,et al.  Thermal radiation from the atmosphere , 1969 .

[9]  R. Dickinson,et al.  Sensitivity of a Land Surface Model to the Diurnal Distribution of Downward Longwave Radiation , 1999 .

[10]  W. Brutsaert.  On a derivable formula for long-wave radiation from clear skies , 1975 .

[11]  S. Idso,et al.  Comparison of long‐wave radiation calculation methods over the United States , 1983 .

[12]  S. Idso.  A set of equations for full spectrum and 8- to 14-μm and 10.5- to 12.5-μm thermal radiation from cloudless skies , 1981 .

[13]  S. B. Idso,et al.  A comparison of two formula types for calculating long‐wave radiation from the atmosphere , 1978 .

[14]  W. Brutsaert,et al.  Cloud effect in the estimation of instantaneous downward longwave radiation , 1993 .

[15]  John H. C. Gash,et al.  Longwave Radiation from Clear Skies in Niger: A Comparison of Observations with Simple Formulas , 1993 .

[16]  Esmael Malek,et al.  Evaluation of effective atmospheric emissivity and parameterization of cloud at local scale , 1997 .