The Estimation of Clear Sky Atmospheric Emittance at High Altitudes

The estimation of clear sky atmospheric emittance in mountainous regions from screen-level climatological data poses several problems, both with respect to the implicit assumptions of the models and features of the input data. The significance of these problems is discussed for a site in the Front Range of Colorado (3,500 m). A modified form of the Brunt model is presented for use at this altitude for the summer months of June, July, and August.For estimates of atmospheric emittance in the region examined, it is preferable to use a model based on observations of both humidity and temperature. The predictive power of models which use temperature only as input is markedly less significant for single-point estimates at 12-hr intervals. It is shown that the use of screen-level data will result in a sizable error in the model predictions and that equivalent pressure level sounding data from a nearby radiosonde station is preferable as input.