The Solar Backscatter Ultraviolet and Total Ozone Mapping Spectrometer (SBUV/TOMS) for NIMBUS G

The Solar Backscatter Ultraviolet and Total Ozone Mapping Spectrometer (SBUV/TOMS) experiment scheduled for launch on NIMBUS G is an expanded capability version of the Backscatter Ultraviolet (BUV) instrument, which has been providing useful data for deducing ozone vertical profiles since its launch aboard the NIMBUS-4 satellite in April 1970. Evaluation of the BUV data has led to a number of design changes on the SBUV/TOMS that will improve our knowledge of the global stratospheric ozone distribution. The BUV instrument sounded ozone in the nadir direction only, and under certain orbital conditions the data were influenced by charged particles in the earth's radiation belts. The SBUV/TOMS instrument has a wider wavelength range, a cross-course mapper, and special provisions for minimizing the effects of space radiation. The BUV instrument is a double (tandem) Ebert-Fastie spectrophotometer measuring spectral intensities at 12 wavelengths from 2555 A to 3398 A with a 10-A bandpass. The SBUV is similar in design to the BUV. It features a state-of-the-art double monochromator that maximizes throughput while providing good wavelength resolution, accuracy, and very high stray-light rejection (106). The TOMS is an ozone mapping system utilizing a close replica of the first monochromator of the SBUV.