Middle Atmosphere High Resolution Spectrograph Investigation

• Published in: Journal of Geophysical Research 1999-07, Vol.104 (D13), p.16
• Main Authors: Conway, Robert R, Stevens, Michael H, Brown, Charles M, Cardon, Joel G, Zasadil, Scott E, Mount, George H
• Format: Article
• Language: English
• ISSN: 0148-0227

The Middle Atmosphere High Resolution Spectrograph Investigation (MAHRSI) was developed specifically to measure the vertical density profiles of hydroxyl (OH) and nitric oxide (NO) in the middle atmosphere from space. MAHRSI was launched on its first flight in November 1994 on the CRISTA-SPAS satellite that was deployed and retrieved by the Space Shuttle. The instrument measured the radiance profiles of UV solar resonance fluorescence on the Earth's limb with a spectral resolving power of 15,600 at a wavelength of 308 nm and 7200 at 215 nm. The instantaneous height of the FOV projected to the tangent point was about 300 m. OH limb radiance measurements were made between altitudes of 90 and 30 km, and each limb scan extended over a horizontal distance of 1200 km. For NO a limb scan extended between altitudes of 140 and 76 km and over a horizontal distance of 700 km. Observations were made from 52 deg S latitude to 62 deg N latitude. The OH measurements were inverted to provide the first global maps of the vertical distribution of OH between 90 and 50 km. The data show a detailed history of the morning formation of a strongly peaked layer of OH at an altitude of 68 km. This paper provides a detailed description of the experiment and instrumentation and of the algorithms used to reduce the spectral data and perform the inversions, and presents examples of key results from the 1994 flight. (Author)