Detection Sensitivities and Measurement Accuracies for Tropospheric Species Using the TES Instrument on EOS/B

The EOS-B/TES (Tropospheric Emission Spectrometer) instrument is a Fourier Transform spectrometer which views the earth's atmosphere in either a nadir mode, with a spectral resolution of 0.1 cm–1, or in a limb sensing mode, with a spectral resolution of 0.025 cm–1. The spectral region covered is between 600 and 4350 cm–1 as listed in Table 1. The broad spectral coverage and the radiometric calibration of this instrument allow the determination of the atmospheric temperature profile, surface brightness temperature and concentration profiles of the minor infrared active gases. The instrument simultaneously views the atmosphere in 4 separate spectral regions; each region possesses a series of filters which may be programmed into position (see Table 1) and a separate focal plane with a linear array of 32 adjacent detectors (only the central 16 are used at the limb). The optical arrangement allows viewing in the limb mode with a 2 x 20 km field of view for each detector at the tangent point with the long dimension being horizontal and the 16 detectors stacked vertically. In the nadir mode the footprint of each of these detectors is 0.5 by 5.0 km or 5 by 50 km depending on the selected field optics. The spectrometer optics are cooled and the detector arrays are selected such that the signal/noise in each of the narrow bands is essentially source limited.