Measurements of short-chain alcohols and aldehydes as important precursors of tropospheric radicals and ozone: Development and application of new methods to measure biosphere-atmosphere exchange fluxes and tropospheric mixing ratios

• Applicant: Dr. Gunnar W. Schade
• Subject Area: Atmospheric Science
• Term: from 2002 to 2006
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5366601

Scientific knowledge on biogenic volatile organic compounds (VOCs) has increased dramatically over the last decade. However, little is known about budgets of oxygenated VOCs (OVOCs), many of which are long-lived atmospheric constituents that have recently been discovered to have major sources in the terrestrial biosphere. In particular the OVOCs acetone and methanol are highly abundant in rural and remote regions. Their ubiquitous abundance in the upper troposphere substantially contributes to global photochemistry through production of odd hydrogen (HOx), and warrants a closer evaluation of their sources and sinks in the atmosphere. We propose to measure OVOC mixing ratios and fluxes in managed ecosystems, namely agriculture and grasslands, which are likely to be significant sources. Two relatively new measurement methods will be interfaced with modern micrometeorological measurement techniques, and field campaigns will be carried out in Germany in cooperation with the Institut für Umweltphysik (IUP) at the University of Bremen and the Landwirtschaftskammer Weser-Ems in Oldenburg. Relating measured fluxes to their environmental drivers will enable us to define or improve upon important parts of the regional and global budgets of OVOCs. This, in turn, will provide much needed data for atmospheric photochemistry models. Furthermore, in-situ measurements of formaldehyde will provide supportive data for the instituts's research group as well as help in validating remotely sensed formaldehyde data acquired from the institute's SCIAMACHY instrument onboard the ENVISAT-1 satellite, to be launched in winter 2001.

• DFG Programme: Independent Junior Research Groups
• Major Instrumentation: PTR-Massenspektrometer