A dedicated robust instrument for water vapor generation at low humidity for use with a laser water isotope analyzer in cold and dry polar regions.

• Main Authors: Leroy-Dos Santos, Christophe, Casado, Mathieu, Prié, Frédéric, Jossoud, Olivier, Kerstel, Erik, Kassi, Samir, Fourré, Elise, Landais, Amaëlle
• Format: Text
• Language: English
• Published: 2020
• Subjects: Antarctic; Concordia Station; Antarc*
• Online Access: https://doi.org/10.5194/amt-2020-345; https://amt.copernicus.org/preprints/amt-2020-345/

Obtaining precise continuous measurements of water vapor isotopic composition in dry places (polar or high-altitude regions) is an important challenge. The current limitation is the strong influence of humidity on the measured water isotopic composition by laser spectroscopy instruments for low humidity levels (below 3000 ppmv). This problem is addressed by determining the relationships between humidity and measured δ 18 O and δD of known water standards. We present here the development of a robust field instrument able to generate water vapor, down to 70 ppmv, at very stable humidity levels (average 1σ lower than 10 ppmv). This instrument, operated by a Raspberry interface, can be coupled to a commercial laser spectroscopy instrument: it turned to be very stable in an autonomous mode during more than one year at the East Antarctic Concordia station.