Assessment of clear and cloudy sky parameterizations for daily downwelling longwave radiation over different land surfaces in Florida, USA

摘要

Clear sky downwelling longwave radiation (R-1dc) and cloudy sky downwelling longwave radiation (R-1d) formulas were tested across eleven sites in Florida. The Brunt equation, using air vapor pressure and temperature measurements, provides the best R-1dc 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 R-1d calculations. This combined approach requires no local calibration and estimates R-1d with a root mean square error of less than around 13 Wm(-2) and squared correlation coefficients that typically exceed 0.9. Citation: Choi, M., J. M. Jacobs, and W. P. Kustas (2008), Assessment of clear and cloudy sky parameterizations for daily downwelling longwave radiation over different land surfaces in Florida, USA, Geophys. Res. Lett., 35, L20402, doi: 10.1029/2008GL035731.