Atmospheric constraints on the methane emissions from the East Siberian Shelf

• Published in: Atmospheric Chemistry and Physics
• Main Authors: Berchet, Antoine, Bousquet, Philippe, Pison, Isabelle, Locatelli, Robin, Chevallier, Frederic, Paris, Jean-Daniel, Dlugokencky, Ed, Laurila, Tuomas, Hatakka, Juha, Viisanen, Yrjo, Worthy, Doug, Nisbet, Euan, Fisher, Rebecca, France, James, Lowry, David, Ivakhov, Viktor, Hermansen, Ove
• Other Authors: Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Modélisation INVerse pour les mesures atmosphériques et SATellitaires (SATINV), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), ICOS-RAMCES (ICOS-RAMCES), NOAA Earth System Research Laboratory (ESRL), National Oceanic and Atmospheric Administration (NOAA), Finnish Meteorological Institute (FMI), Environment Canada (Toronto), Royal Holloway University of London (RHUL), A. I. Voeikov Main Geophysical Observatory (MGO), Norwegian Institute for Air Research (NILU)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2016
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; Arctic; Ice; permafrost; Sea ice
• Online Access: https://hal.science/hal-02950515; https://hal.science/hal-02950515/document; https://hal.science/hal-02950515/file/acp-16-4147-2016.pdf; https://doi.org/10.5194/ACP-16-4147-2016

International audience Subsea permafrost and hydrates in the East Siberian Arctic Shelf (ESAS) constitute a substantial carbon pool, and a potentially large source of methane to the atmosphere. Previous studies based on interpolated oceanographic campaigns estimated atmospheric emissions from this area at 8-17 TgCH 4 yr −1. Here, we propose insights based on atmospheric observations to evaluate these estimates. The comparison of high-resolution simulations of atmospheric methane mole fractions to continuous methane observations during the whole year 2012 confirms the high variability and heterogeneity of the methane releases from ESAS. A reference scenario with ESAS emissions of 8 TgCH 4 yr −1 , in the lower part of previously estimated emissions, is found to largely overestimate atmospheric observations in winter, likely related to overestimated methane leakage through sea ice. In contrast, in summer, simulations are more consistent with observations. Based on a comprehensive statistical analysis of the observations and of the simulations, annual methane emissions from ESAS are estimated to range from 0.0 to 4.5 TgCH 4 yr −1. Isotopic observations suggest a bio-genic origin (either terrestrial or marine) of the methane in air masses originating from ESAS during late summer 2008 and 2009.