Tropospheric OH, HO2, N02, and NO by Resonance Emission: Instrumentation and Measurements of Abundances and Fluxes

The number of detection techniques for the hydroxyl radical has blossomed within the last few years. In addition to long-path absorption and chemical conversion are the improved in situ, spectroscopic fluorescence methods. Such methods can have both the sensitivity and specificity that is required for versatile measurements from either remote ground-based sites or from aircraft. They have for the last two years pursued the measurement technique for detection of tropospheric OH and HO2 by laser induced fluorescence in chambers at low pressures. This technique is now sufficiently well developed that an instrument can be built which can be used either from remote platforms or from aircraft. This award will support the building of this instrument and allow a series of ground-based field measurements and intercomparisons. This instrument will be designed so that it can be mounted in a double rack on an aircraft. Actual use on an aircraft will require only the design and construction of an air intake duct and slight changes to the orientation of the air inlet.