Extended Abstract (104K)P4.21
Real-time profiles of organic trace gases in the Arctic boundary layer obtained during the Arctic Ocean Expedition (AOE-2001)
Michael L. Jensen, CIRES/Univ. of Colorado, Boulder, CO; and A. Wisthaler, A. Hansel, P. O. G. Persson, and B. Templeman
PTR-MS (Proton-Transfer-Reaction Mass Spectrometry) is a chemical ionization mass spectrometry technique that allows for on-line measurements of organic trace gases in air at pptv levels. A rugged and field portable PTR-MS instrument developed at the University of Innsbruck was successfully deployed during the Arctic Ocean Expedition (AOE-2001).
In a new experimental approach a kite or aerodynamic tethered balloon was employed as a lifting platform for a 200 m long PFA Teflon tube connected to the sample gas inlet of the PTR-MS apparatus. Both systems were operated from an ice camp set up on a moderate-sized floe during a three-week drift near the North Pole. The inlet tube was pumped by a diaphragm pump with high flow-rate limiting the residence time of the air in the inlet to less than 10 s. The inlet was lifted at a constant speed of roughly 9 m min-1. Selected organic trace gases (including acetonitrile, acetone and dimethyl sulfide) were measured with 20 s time resolution resulting in vertical profiles from the ground up to roughly 200 m with a vertical resolution of about 3 m.
The inlet was typically raised to near the top of the boundary layer and on a few occasions completely through it. Boundary layer height was determined a-priori using data from the meteorological payload flown on the previous kite or balloon flight. In addition, backscatter returns from a monostatic sodar operated by NOAA's Environmental Technology Laboratory (ETL) operated close to the kite and balloon launch site were used to determine boundary layer height and kite or balloon altitude in real-time.
Theoretical limits of the maximum altitude attainable by the system will be presented. Altitude is limited by a combination of platform type, wind conditions, and inlet tube weight, inside and outside diameters. The utility of this system for profiling the stable boundary layer has been clearly demonstrated by this initial test.
Poster Session 4, Stable BLs; Chemistry and Dispersion in the ABL
Tuesday, 16 July 2002, 2:00 PM-2:00 PM
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