Balloon borne LIDAR measurements of stratospheric hydroxyl radical

Abstract

A balloon‐borne laser radar (LIDAR) system for the determination of stratospheric hydroxyl radical concentration has been constructed and flown by Goddard Space Flight Center. The system measured hydroxyl in the 34–37 km altitude range throughout an afternoon and early evening yielding the first post‐sunset hydroxyl determinations ever obtained. Daytime values (∼5×10 6 cm −3 ) were somewhat lower than previous measurements using in situ resonance fluorescence. Nighttime values (∼7×10 5 cm −3 @2100 CDT) were higher than predicted by current one‐dimensional (1‐D) models. Possible sources of these discrepancies along with improvements possible in future systems are outlined.