Clear sky downwelling longwave radiation (Rldc) and cloudy sky downwelling longwave radiation (Rld) formulas were tested across eleven sites in Florida. The Brunt equation, using air vapor pressure and temperature measurements, provides the best Rldc estimates with a root mean square error of less than around 12 Wm−2 across all sites. The Crawford and Duchon's cloudiness factor with Brunt equation is recommended for Rld calculations. This combined approach requires no local calibration and estimates Rld with a root mean square error of less than around 13 Wm−2 and squared correlation coefficients that typically exceed 0.9.
Earth Systems Research Center
Geophysical Research Letters
American Geophysical Union (AGU)
Digital Object Identifier (DOI)
Choi, M., J.M. Jacobs, and W. Kustas. 2008. Assessment of clear and cloudy sky parameterizations for daily downwelling longwave radiation over different land surfaces in Florida, USA. Geophysical Research Letters. 35. L20402, doi:10.1029/2008GL035731.
Copyright 2008 by the American Geophysical Union.