A Framework to Study Mixing Processes in the Marine Boundary Layer Using Water Vapor Isotope Measurements

• Published in: Geophysical Research Letters
• Main Authors: Benetti, Marion, Lacour, Jean-Lionel, Sveinbjörnsdóttir, Árný, Aloisi, G., Reverdin, G., Risi, C., Peters, A. J., Steen‐Larsen, H. C.
• Other Authors: Jarðvísindastofnun (HÍ), Institute of Earth Sciences (UI), Verkfræði- og náttúruvísindasvið (HÍ), School of Engineering and Natural Sciences (UI), Háskóli Íslands, University of Iceland
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union (AGU) 2018
• Subjects: Geophysics; Marine boundary layer; Water vapor isotopes; Evaporation; Jarðeðlisfræði; Veðrahvolf; Norður-Atlantshaf; Vatnafræði; Samsætur; Herve; Iceland; North Atlantic
• Online Access: https://hdl.handle.net/20.500.11815/2024; https://doi.org/10.1002/2018GL077167

Publisher's version (útgefin grein) We propose a framework using water vapor isotopes to study mixing processes in the marine boundary layer (MBL) during quiescent conditions, where we expect evaporation to contribute to the moisture budget. This framework complements the existing models, by taking into account the changing isotopic composition of the evaporation flux (δe), both directly in response to the mixing and indirectly in response to mixing and surface conditions through variations in MBL humidity. The robustness of the model is demonstrated using measurements from the North Atlantic Ocean. This shows the importance of considering the δe variability simultaneous to the mixing of the lower free troposphere to the MBL, to simulate the MBL water vapor, whereas a mixing model using a constant δe fails to reproduce the data. The sensitivity of isotope observations to evaporation and shallow mixing further demonstrates how these observations can constrain uncertainties associated with these key processes for climate feedback predictions. The Tudor Hill Marine Atmospheric Observatory in Bermuda is supported by the NSF OCE‐1130395, and the assistance of Matthew Hayden is gratefully acknowledged. Observations at Bermuda were supported by the Danish Council for Independent Research—Natural Sciences grant 10‐092850, the Carlsberg Foundation, the Icelandic Centre for Research—Equipment Fund grant 1202340031, and the Icelandic Research Fund grant 152229‐052. STRASSE was supported by two LEFE/IMAGO grants (Strasse and Strasse/SPURS), with support from IPSL and OSU Ecce Terra. The authors acknowledge “Les Amis du Jeudi et du Dimanche” and Herve Legoff for the installation on the RARA AVIS. The authors thank the National Power Company of Iceland Landsvirkjun for their contribution to this research. The data at Bermuda are available in the supporting information. The cruise data are provided at http://cds‐espri.ipsl.fr/isowvdataatlantic/. Peer reviewed