HR: 09:30h
AN: A21D-07 INVITED     [Abstracts]
TI: Airborne Observations of NO, NOy, Particles, and Other Trace Gases Over the Antarctic Continent During ANTCI 2003
AU: * Davis, D D
EM: douglas.davis@eas.gatech.edu
AF: Georgia Institute of Technology, School of Earth and Atmospheric Sciences, Atlanta, GA 30332
AU: Blake, D R
EM: dblake@orion.oac.uci.edu
AF: U. of California, Irvine, Department of Chemistry, Irvine, CA 92612
AU: Weber, R J
EM: rweber@eas.gatech.edu
AF: Georgia Institute of Technology, School of Earth and Atmospheric Sciences, Atlanta, GA 30332
AU: Buhr, M
EM: marty@sonomatech.com
AF: Sonomatech, 1360 Redwood Way, Suite C, Petaluma, CA 95954
AB: The Investigation of Sulfur Chemistry in the Antarctic Troposphere (ISCAT) field studies in 1998 and 2000 generated several surprising atmospheric-chemistry findings. Based on observations at South Pole's (SP) Atmospheric Research Observatory, very little gas phase sulfur was measured during these studies, but unexpectedly high levels of NO were recorded (e.g., 650 pptv). Although it has now been convincingly demonstrated that the source of this NO is its emission from the snowpack due to the photolysis of nitrate ions, major unanswered questions persist. Among the more significant of these has been the issue of "the spatial extent of this phenomenon". Do these highly elevated levels of NO at SP occur only in the immediate region surrounding SP? If not, how far out do they range over the 1000+ km wide Antarctic plateau? Equally important is the question: what does the altitudinal profile of NO look like over the plateau, and does the presence of elevated NO lead to the formation of an OH oxidizing canopy over this region? There also remain the pivotal issues of identifying the primary source of nitrogen to the plateau as well as determining the major pathways by which this reactive nitrogen is lost from near surface snow (~ 1m). During the Antarctic Tropospheric Chemistry Investigation (ANTCI), an airborne platform was added to extend the sampling already taking place at SP. The Twin Otter aircraft provided the opportunity to examine several of the issues raised above requiring three-dimensional sampling. Over the time period of 27 November to 6 December 2003, a total of 10 data collection flights were flown. Major species sampled were NO, NOy and CN particles. The NO and NOy were measured using a chemiluminescence instrument equipped with a Molybdenum converter, and particles were measured using a standard CN counter. More limited observations were made of DMS, CHBr3, CH3I, CH3ONO2, and other low molecular weight NMHC's using evacuated canisters in conjunction with grab-sampling. Details concerning the results from these flights will be presented.
DE: 9310 Antarctica
DE: 0300 ATMOSPHERIC COMPOSITION AND STRUCTURE
DE: 0365 Troposphere--composition and chemistry
DE: 0368 Troposphere--constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting