The atmosphere constitutes an extremely complex mixture of thousands of trace constituents that permanently react and re-distribute within the atmosphere itself as well as adjoined compartments such as the biosphere or the ocean. The atmosphere can thus be viewed as a giant natural chemical reactor.
The group Tropopause (TOP) is particularly interested in the budgets of trace gases in the upper troposphere and lower stratosphere (UTLS), i.e. between ~6 km and ~25 km. The layer sandwiched between the two spheres UT and LS, the tropopause, shows an altitude of ~17 km in the tropics and 8-12 km in mid- and polar latitudes. The UTLS plays an essential role in controlling climate on earth. In spite of its importance and due to its extreme dynamical and chemical complexity, the UTLS is still one of the least well understood regions of the atmosphere.
The main scientific objectives of our group are:
- to better understand the (bi-directional) exchange of trace gases between stratosphere and troposphere (STE). We are thus strongly engaged in the dynamics of the UTLS (tropopause dynamics, convection, slow cyclonic lofting).
- to better quantify the budgets of ozone, organic compounds, water (as vapour and in clouds / aircaft contrails), carbon dioxide, and methane in the UTLS, and to better distinguish between variations due to transport and those caused by chemistry.
- and certainly how these trace gas budgets and processes change with time ("global change"), and what are the consequences of these changes for Earth's climate ("climate change").
For achieving this goal we develop, construct and thereafter deploy in-situ instruments on board research and passenger aircraft. Applied techniques are UV photometry, chemiluminescence detection, chemical mass spectrometry, tunable diode laser absorption spectroscopy, photo-acoustic laser spectroscopy, integrated cavity output spectroscopy, and chilled mirror frost point hygrometry. Main project currently is CARIBIC, where we run five in-situ instruments on board an Airbus A340-600 of Lufthansa AG as of May 2005. We further have developed three in-situ instruments for the new German research aircraft HALO (with a first deployment in July/August 2012), and contribute to the European research grant MUSICA.
.... in our opinion, an actual and fascinating research topic and work. If you are interested in joining our group, see under Vacancies.