AN EVALUATION OF ATMOSPHERIC CORRECTIONS OF RADIOMETRIC SURFACE TEMPERATURES FOR A SEMIARID RANGELAND WATERSHED

As part of an interdisciplinary effort to describe the hydrologic and surface energy balance of a semiarid rangeland watershed, remote and g round radiometric surface temperature measurements were collected at t he Walnut Gulch experimental watershed near Tombstone, Arizona. To cor rect for atmospheric effects on the remotely sensed data, radiosondes were launched on and off the watershed, and the LOWTRAN7 radiative tra nsfer model was used to evaluate these observed as well as two standar d atmospheric profiles. Comparison of the results for five atmospheric profiles, for each of three days, showed no correlation between radio sonde location or launch time and resulting temperature corrections. C omparison of corrected temperatures using five different atmospheric p rofiles on each of two days with the corresponding ground-based radiom etric temperatures demonstrated significant errors (greater than 2.0-d egrees-C) as the atmospheric profiles generally yielded underestimates of ground radiometric temperatures.