Monitoring potential photochemical interference in laser-induced fluorescence measurements of atmospheric OH

M.K. Dubey, T.F. Hanisco, P.O. Wennberg, J.G. Anderson
PS 045, Molecular Physics Laboratory, SRI International, 333 Ravenswood Avenue, Menlo Park, CA 94025

Abstract:

In situ laser-induced fluorescence measurements of atmospheric OH are susceptible to interference from laser generated OH, particularly in the troposphere. To quantify this interference we implement the addition of perfluoropropene, , for the chemical removal of OH from the ambient air. The removal rate of OH by is determined in the laboratory using the discharge flow technique. Over the temperature range 249 to 296 K the rate constant is , independent of pressure. In situ measurements using addition are performed in both aircraft-borne and ground-based experiments. These studies show that laser excitation of the transition (282 nm) at high pulse repetition rates and low peak power can provide reliable and sensitive measurements of tropospheric OH.

AGU Index Terms: 0394 Instruments and techniques; 0365 Troposphere-composition and chemistry; 0317 Chemical kinetic and photochemical properties; 0340 Middle atmosphere-composition and chemistry
Keywords/Free Terms: Hydroxyl radical, LIF OH measurements, monitor photochemical interference, OH + perfluoropropene kinetics, OH modulation by perfluoropropene.

Geophysical Res. Ltrs. 96GL03008
Vol. 23 , No. 22 , p. 3215