HR: 1330h
AN: A52A-0769    [PDF]
TI: The Temporal and Spatial Variations of the D/H Ratio of H$_{2}$ in the Free Troposphere: CARIBIC Results
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: 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: Rf\"{o}ckmann, T
EM: T.Roeckmann@mpi-hd.mpg.de
AF: Max Planck Institute for Nuclear Physics, Atmospheric Physics Division, Saupfercheckweg 1, Heidelberg, 69117 Germany
AB: A new technique for the analysis of the D/H ratio in atmospheric H$_{2}$ using continuous-flow gas-chromatography isotope-ratio mass-spectrometry (GC/IRMS) that requires small amounts ($\sim$ 300 mL, STP) of sample air and produces excellent results has been developed and applied to air samples from the CARIBIC passenger aircraft project. 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 for a projected period of 10 years. The isotopic ratios and atmospheric concentrations of H$_{2}$ were measured for 3 flights over Europe and Africa carried out in 2000. The flight tracks cover from $50\deg$N to $30\deg$S allowing us to investigate hemispheric variation along the route. As the air samples for 3 flights had been collected at different seasons of boreal spring (May), summer (July), and early winter (December), the seasonal variation of the isotopic ratios can be investigated. Although, during 3 seasons, biomass burning was always active in the tropics, the D/H isotopic ratios hardly give us clear evidence, except for the boreal summer when biomass burning peaks. A seasonal variation is clearly visible, but the trends are opposite in the two hemispheres: in the northern hemisphere deuterium is enriched in winter (December) and in the southern hemisphere in fall (May), suggesting the major process governing the seasonal variation might be different in the two hemisphere. In addition, the D/H ratios of H$_{2}$ in the southern hemisphere are higher than that in the northern hemisphere, in 3 seasons.
UR: http://www.caribic-atmospheric.com
DE: 0322 Constituent sources and sinks
DE: 0365 Troposphere--composition and chemistry
DE: 0368 Troposphere--constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting