A41A-0011
Airborne Measurements of NOx, NOy, and O3 Using Cavity Ring-Down Spectroscopy

Thursday, 17 December 2015
Poster Hall (Moscone South)
Kyle J Zarzana1, Robert J Wild2, Chelsea R Thompson3, Steven J Sjostedt4, Rebecca A Washenfelder1, William P Dube1, Thomas B Ryerson5 and Steven S Brown1, (1)NOAA Boulder, Boulder, CO, United States, (2)Colorado University/NOAA/ESRL, Boulder, CO, United States, (3)CIRES, Boulder, CO, United States, (4)Georgia Institute of Tech, Atlanta, GA, United States, (5)NOAA, Boulder, CO, United States
Abstract:
NO and NO2 (=NOx) have a large effect on air quality and chemistry. Oxidation reactions transform NOx into other reactive nitrogen species such as PAN, HNO3, organic nitrates and N2O5, which can act either as sinks or reservoirs of NOx. Together with NOx, the sum of these oxidized reactive nitrogen species is termed NOy. Ozone serves as a principal oxidant source for many of these reactions, and it is also produced or destroyed during subsequent chemical cycles. Therefore, simultaneous measurements of all four species (NO, NO2, NOy, and O3) are desirable.

Previous measurements of these species have principally been made by converting the compound of interest to NO, which is then detected using chemiluminescence. Alternatively, these species can be converted to NO2, which can then be detected using absorption spectroscopy. The use of a cavity ring down instrument allows for the accurate and rapid detection of NO2 in a compact and robust platform suitable for field deployments on numerous platforms, including vehicles and airplanes.

In this work we describe the first aircraft deployment of a four-channel cavity ring-down instrument capable of simultaneously measuring NO2, NO, NOy, and O3. This deployment took place during the 2015 Shale Oil and Natural Gas Nexus (SONGNEX) field campaign in the western United States. The instrument flew in tandem with a chemiluminescence instrument, which measured the same set of compounds. A separate instrument that measured NO2 by a related absorption technique, broadband cavity enhanced spectroscopy (BBCES) was also on board the aircraft. An intercomparison between these instruments will be presented, as well as data from the SONGNEX flights that illustrate the capabilities of the CRDS insrument.

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