An aircraft instrument design for in situ tropospheric OH measurements by laser induced fluorescence at low pressuresThe hydroxyl radical (OH) is important for many processes involved in tropospheric chemistry. For instance, it initiates the photochemical degradation of gases that cause global climate change, such as methane and the chlorofluorocarbon substitutes (HCFCs). Because of its reactivity, its abundances are less than 0.1 pptv. Thus, OH has been very difficult to measure accurately, despite its importance. Techniques have evolved, however, so that good measurements of tropospheric OH abundances are now possible. One of these techniques that is adaptable to aircraft measurements is the laser induced fluorescence detection of the OH radical in a detection chamber at low pressures. The current ground-based instrument, which can be readily adapted to aircraft, can detect OH abundances of 1.4 x 10 exp 5 OH molecules/cu cm with S/N = 2 in 30 sec, and 5 x 10 exp 4/cu cm in 5 min.
Document ID
19930067531
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Brune, William H. (NASA Langley Research Center Hampton, VA, United States)
Stevens, Philip S. (NASA Langley Research Center Hampton, VA, United States)
Mather, James H. (Pennsylvania State Univ. University Park, United States)
Date Acquired
August 16, 2013
Publication Date
January 1, 1993
Publication Information
Publication: In: Optical methods in atmospheric chemistry; Proceedings of the Meeting, Berlin, Germany, June 22-24, 1992 (A93-51501 22-35)
Publisher: Society of Photo-Optical Instrumentation Engineers