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UP: Fachverband Umweltphysik
UP 13: Methoden - Fernerkundung, Messverfahren und Datenauswertung
UP 13.2: Talk
Thursday, February 28, 2013, 09:30–09:45, HS 5
2.7µm open-path TDL-spectrometer for simultaneous in situ H2 18O/H2 16O measurements in clouds — •Benjamin Kühnreich1, 2, Jan Habig3, Steven Wagner2, Harald Saathoff3, Liz Moyer4, and Volker Ebert1, 2 — 1Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig — 2Center of Smart Interfaces, Technische Universität Darmstadt, Petersenstr. 32, 64287 Darmstadt — 3Karlsruhe Institute of Technology, Herrmann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen — 4Department of Geophysical Sciences, University of Chicago
Isotopic tracers are widely used to investigate environmental processes. Recently there has been interest in using changes in the isotopic composition of water vapour to investigate microphysical cloud formation processes. We report here on the development of a new instrumentation for the measurement of isotopic composition changes in clouds in the DFG/NSF funded ISOCLOUD project. In situ open-path TDLAS provides a non-invasive, sampling free measurement technique appropriate for this purpose. We describe one of the ISOCLOUD instruments, an open-path TDL around 2.7µm, and show preliminary data from its first application in the cloud simulation chamber AIDA for the measurement of the isotopic ratio of H2 18O/H2 16O. We discuss current and future in situ detection limits. Current data based on 280 m absorption path indicate detection limits of 0.2 ppb for H2 18O and 80.6 ppb for H2 16O.