Jena 2013 – scientific programme

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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 Kühnreich^{1, 2}, Jan Habig³, Steven Wagner², Harald Saathoff³, Liz Moyer⁴, and Volker Ebert^{1, 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.