Infrared Land Surface Emissivity Retrieval from S-HIS Upwelling Radiance Measurements During SAFARI 2000

The Southern African Regional Science Initiative (SAFARI 2000) field campaign provided an opportunity to study various infrared land surface emission characteristics. High spectral resolution upwelling radiance measurements were acquired by the Scanning High-resolution Interferometer Sounder (S-HIS). Results will be shown from flights over the Okavango Delta in Northern Botswana on 27 Aug 2000. A series of 6 parallel flight lines were flown which were able to map the entire delta region. S-HIS derived land surface emissivities will be compared to a database of AERI ground measurements to best determine surface characteristics. The S-HIS measures upwelling emission spectra in continuous spectral coverage from 3.3 to 16.7 microns at 0.5 wavenumber resolution. This coverage is divided into three bands with separate detectors (two photoconductive HgCdTe and one InSb) to achieve the required noise performance. The bands use a common field stop to ensure accurate spatial co-alignment. S-HIS measurements occur at 0.5 second dwell times, which allow imaging with 2-3 km surface resolution during cross-track scanning, from a nominal ER-2 altitude of 18 km. Ambient and hot reference blackbodies are viewed as part of each cross-track scan, providing updated calibration information every 20 to 30 seconds.