Validation of the Schwartz and Hon algorithm at low grazing angles

Abstract

An experimental validation of the Schwartz-Hon computer code for emissivity of the rough sea surface in the grazing angle region was carried out using an AGEMA 780 thermovision radiometric sensor. The experimental measurements were made in Monterey Bay using a meteorological suite mounted on the Research Vessel Point Sur, with coordinated radiosonde launches. Predicted sea surface radiance was computer from reflected sky radiance and thermal sea emission, using the Schwartz-Hon algorithm for sea emissivity and equivalent specular incidence angle. AGEMA sea radiance measurements were compared with the model predictions as a function of observation angle and were found to agree within 8% for elevation angles from zero to 5 degrees. PC-TRAN sky radiance computations for the grazing angle region agreed with AGEMA measurements within approximately 12%.