BALLOON BORNE LIDAR MEASUREMENTS OF STRATOSPHERIC HYDROXYL RADICAL

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 (approximately 5 multiplied by 10**6 cm** minus **3) were somewhat lower than previous measurements using in situ resonance fluorescence. Nighttime values (approximately 7 multiplied by 10**5 cm** minus **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.