| Abstract/Description or Keywords |
Hourly atmospheric longwave radiation (L?) flux densities observed at an alpine tundra site in southern British Columbia were compared to eight different L? models that utilized screen-level temperature and/or vapor pressure input data. Models tested were the Stefan-Boltzmann equation using an effective atmospheric emissivity of .70, and the models formulated by Brunt, LeDrew, Swinbank, Idso, Idso-Jackson, Brutsaert, and Berdahl-Martin. All models were tested on both cloudless and cloudy sky conditions. Most models performed well, with the exception of the LeDrew model. Overall, the Idso-Jackson model was superior. The results demonstrated that L? could be reliably estimated from air temperature alone, and challenged the accepted notion that L? models do not work effectively in mountainous environments. Measured terrestrial longwave radiation (L?) varied according to the dictates of the Stefan-Boltzmann Law. Comparisons between measured L? and surface (skin) temperature indicated that blackbody assumptions of surface emissivity were appropriate. [Key words: climatology, longwave radiation, alpine tundra, British Columbia.] |
