Atmos. Chem. Phys., 18, 17207–17224, 2018 https://doi.org/10.5194/acp-18-17207-2018 © Author(s) 2018. This work is distributed under the Creative Commons Attribution 4.0 License. Methane at Svalbard and over the European Arctic Ocean Stephen M. Platt1, Sabine Eckhardt1, Benedicte Ferré2, Rebecca E. Fisher3, Ove Hermansen1, Pär Jansson2, David Lowry3, Euan G. Nisbet3, Ignacio Pisso1, Norbert Schmidbauer1, Anna Silyakova2, Andreas Stohl1, Tove M. Svendby1, Sunil Vadakkepuliyambatta2, Jürgen Mienert2, and Cathrine Lund Myhre1 1NILU – Norwegian Institute for Air Research, P.O. Box 100, 2027 Kjeller, Norway 2CAGE-Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geosciences, UiT The Arctic University of Norway, 9037 Tromsø, Norway 3Department of Earth Sciences, Royal Holloway, University of London, Egham, UK Correspondence: Stephen M. Platt (
[email protected]) Received: 15 June 2018 – Discussion started: 5 July 2018 Revised: 12 October 2018 – Accepted: 31 October 2018 – Published: 5 December 2018 Abstract. Methane (CH4) is a powerful greenhouse gas. long-range transport from land-based sources, lending confi- Its atmospheric mixing ratios have been increasing since dence to the present inventories for high-latitude CH4 emis- 2005. Therefore, quantification of CH4 sources is essential sions. However, we also identify a potential hotspot region ◦ for effective climate change mitigation. Here we report ob- with ocean–atmosphere CH4 flux north of Svalbard (80.4 N, ◦ −2 −1 servations of the CH4 mixing ratios measured at the Zep- 12.8 E) of up to 26 nmol m s from a large mixing ra- pelin Observatory (Svalbard) in the Arctic and aboard the re- tio increase at the location of 30 ppb.