HR: 08:40h
AN: A51C-03    [PDF]
TI: CARIBIC Observations of Non-Methane Hydrocarbons (NMHCs) in the UT/LS: Biomass Burning in the Tropics and Anthropogenic Pollution in the Extra-Tropics
AU: Brenninkmeijer, C A
EM: carlb@mpch-mainz.mpg.de
AF: Max Planck Institute for Chemistry, Atmospheric Chemistry Division, P.O.Box 3060, Mainz, 55020 Germany
AU: * Rhee, T S
EM: rhee@mpch-mainz.mpg.de
AF: Max Planck Institute for Chemistry, Atmospheric Chemistry Division, P.O.Box 3060, Mainz, 55020 Germany
AU: Slemr, F
EM: slemr@mpch-mainz.mpg.de
AF: Max Planck Institute for Chemistry, Atmospheric Chemistry Division, P.O.Box 3060, Mainz, 55020 Germany
AU: Mf\"{u}hle, J
EM: jens@gaslab.ucsd.edu
AF: Max Planck Institute for Chemistry, Atmospheric Chemistry Division, P.O.Box 3060, Mainz, 55020 Germany
AU: Fischer, H
EM: hofi@mpch-mainz.mpg.de
AF: Max Planck Institute for Chemistry, Atmospheric Chemistry Division, P.O.Box 3060, Mainz, 55020 Germany
AU: Zahn, A
EM: andreas.zahn@imk.fzk.de
AF: Institute for Meteorology and Climate Research, P.O.Box 3640, Karlsruhe, D-76021 Germany
AU: van Velthoven, P F
EM: velthove@knmi.nl
AF: KNMI (Royal Netherlands Meteorological Institute), P.O.Box 201,, De Bilt, 3730 AE Netherlands
AB: CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrumented Container) used a Boeing 767 on intercontinental flights to measure trace gases and aerosols between November 1997 and April 2002. From April 2004 onwards, a new Lufthansa Airbus A340-600 with a new inlet system and measurement container with 16 experiments will become operational. Here we discuss the results for NMHCs for a flight from the Maldives to Germany, June 2000. Twelve air samples of 350 L were collected and analyzed in the laboratory for NMHCs, halocarbons, CH$_{4}$, CO, N$_{2}$O, SF$_{6}$, and isotopic compositions in CO and CO$_{2}$. In the upper troposphere (UT) of the tropics, the concentrations of saturated NMHCs (C2 $-$ C6) were significantly lower and less variable than in the extra-tropics, likely due to enhanced photo-oxidation in summer. A good correlation between long-lived NMHCs and CO, and their emission ratios imply that the air masses come from biomass burning regions. By contrast, the concentrations of all saturated NMHCs in the extra-tropics were greatly augmented. In particular, very high concentrations of several short-lived NMHCs, i.e., {\it n}-pentane, {\it i}-pentane, {\it n}-hexane, were observed near or even in the lowermost stratosphere (LS). Tight anti-correlations between CO and O$_{3}$, the enhancement of ultra-fine particles, and the calculated backward trajectories indicate the occurrence of deep convection of highly polluted air from southern Europe into the lowermost stratosphere. The CARIBIC findings show a direct (fast) injection of polluted air to be a significant source of NMHCs observed in the lowermost stratosphere in the extra-tropics.
UR: http://www.caribic-atmospheric.com
DE: 0322 Constituent sources and sinks
DE: 0340 Middle atmosphere--composition and chemistry
DE: 0341 Middle atmosphere--constituent transport and chemistry (3334)
DE: 0365 Troposphere--composition and chemistry
DE: 0368 Troposphere--constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting