HR: 11:35h
AN: A21F-06    [PDF]
TI: Fine-scale Source Distribution of Biogenic VOCs Measured by Proton-Transfer-Reaction Mass Spectrometry.
AU: * Karl, T
EM: tomkarl@ucar.edu
AF: NCAR, 1875 Table Mesa Dr, Boulder, CO 80305 United States
AU: Potosnak, M
EM: potosnak@ucar.edu
AF: NCAR, 1875 Table Mesa Dr, Boulder, CO 80305 United States
AU: Guenther, A
EM: guenther@ucar.edu
AF: NCAR, 1875 Table Mesa Dr, Boulder, CO 80305 United States
AU: Nemitz, E
EM: nemitz@ucar.edu
AF: NCAR, 1875 Table Mesa Dr, Boulder, CO 80305 United States
AU: Turnipseed, A
EM: turnip@ucar.edu
AF: NCAR, 1875 Table Mesa Dr, Boulder, CO 80305 United States
AU: Baker, B
EM: Brad.Baker@sdsmt.edu
AF: SDST, 501 East St. Joseph Street, Rapid City, SD 57701 United States
AU: Geron, C
EM: Geron.chris@epa.gov
AF: US EPA, 109 TW Alexander Dr., Research Triangle Pa, NC 27711 United States
AB: We have recently deployed Proton-Transfer-Reaction Mass Spectrometry for measuring reactive biogenic trace gases at a loblolly pine plantation in North Carolina (Duke Forest) as well as a primary tropical rainforest in Costa Rica. An automated moveable inlet system allowed observations of the finescale source structure of various biogenics, such as isoprene, MVK+MAC, acetaldehyde, acetone, methanol and monoterpenes within the canopy using an inverse lagrangian dispersion model. The distribution of oxygenated compounds in general shows a complex behavior of emission and deposition. Together with eddy covariance measurements at the top of the canopy, which we compare with enclosure measurements, we are able to quantify finescale exchange processes of VOCs within the canopy. Our measurements demonstrate that the treatment of emission and deposition currently used for modeling oxygenated biogenic VOCs can only be seen as a first order approximation.
DE: 0315 Biosphere/atmosphere interactions
DE: 0322 Constituent sources and sinks
DE: 0365 Troposphere--composition and chemistry
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting