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DEVELOPMENT OF LIGHTWEIGHT INSTRUMENTATION FOR MEASUREMENT OF LONG-LIVED TRACE GASES
Description:
The ozone budget of the upper troposphere is highly uncertain with respect to both chemistry and dynamical effects. Extensive data in the 6 to 12 km region of the atmosphere is needed to constrain the relative roles of various dynamical processes, such as convection and intrusion from the stratosphere. One way to address this data deficit is to take advantage of the sampling capabilities of the fleet of commercial aircraft. To this end, it has been proposed to develop a suite of instruments designed to detect several trace gases that will provide unique signatures of transport phenomena. It is anticipated that the dataset created with this type of program will be useful in the continuing development and testing of global three-dimensional chemical transport models, models of ozone precursor emissions and ambient air quality, and the assessment of the effects of subsonic aviation on ozone distributions.
To accomplish the stated goal, four separate sensors will be combined into a single instrument package suitable for flying in the cargo area of a commercial airliner or other frequently flying plane (i.e., it must be small, lightweight, and autonomous for extended periods of time). Ozone will be measured with a dual-beam ultraviolet absorption instrument, a non-dispersive infrared sensor will be used to detect carbon dioxide, and measurement of water vapor will be accomplished with a tunable diode laser spectrometer. Funding under this grant will support development, testing, and deployment of a prototype, lightweight gas chromatograph system, based on micro-GC technology. A suite of five halocarbons, whose chemical lifetimes in the troposphere span a range from 5 days to 5 years, will be measured. Each of the species selected for this study provides by itself, or in combination with the others, information about the role of one of the dynamical processes controlling ozone distributions in the upper troposphere. Funding from the NASA Atmospheric Effects of Aviation program will support development of the ozone, carbon dioxide and water vapor sensors, packaging, and integration onto a suitable platform.
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