Comparison of SABER OH Measurements to Rocket Photometry Data Jordan Rozum, Gene A. Ware, Doran J. Baker Rocky Mountain NASA Space Grant Consortium, Utah State University

SABER Background SABER Instrument – Sounding of the Atmosphere using Broadband Emission Radiometry TIMED Satellite – Thermosphere Ionosphere Mesosphere Energetics and Dynamics MLTI – Mesosphere Lower Thermosphere/Ionosphere OH VER – Hydroxyl Volume Emission Rate Typical OH altitude profile as measured by SABER SABER orbits the Earth every half-hour, covering 70% of the globe. Scanning approximately every 60 seconds, SABER measures almost 1500 scans per day and has been at it for a decade. In the two OH channels, this gives us nearly 10 million profiles to work with.

Rockets From 1961 to 1986, several rockets were launched with photometers on board to measure the OH layer. The results were cataloged by Baker and Stair in 1988. Because of the Wealth of data SABER provides, we can make matches to these launches. We select for (in order of importance) Solar Zenith Angle Latitude Day of Year Longitude

Peak Width and Altitude The rocket measurements and SABER measurements agree on peak width and altitude: (Rocket Measured Parameters are from Baker and Stair) Rocket Measured Width (FWHM) SABER 1.6 um Measured Width (FWHM) SABER 2.0 um Measured Width (FWHM) Rocket Measured Peak Alt. SABER 1.6 um Measured Peak Alt. SABER 2.0 um Measured Peak Alt. Mean (km) 8.6 7.7 9.0 86.8 84.3 87.7 Standard Deviation (km) 3.1 1.5 2.1 2.6 6.7 2.0

Bifurcation A significant portion of SABER profiles show evidence of OH layer bifurcation The distribution of bifurcation is not uniform among the rocket- SABER matches We are currently investigating possible explanations, such as solar zenith angle bias and other lurking variables

References Baker, D.J. And Stair, A.T. “Rocket Measurements of the Altitude Distributions of the Hydroxyl Airglow”. 6th International Symposium on Solar Terrestrial Physics (1988). SABER Data processed by GATS, Inc. (gats-inc.com)