Estimating methane emissions in the Arctic nations using surface observations from 2008 to 2019

• Published in: Atmospheric Chemistry and Physics
• Main Authors: Wittig, Sophie, Berchet, Antoine, Pison, Isabelle, Saunois, Marielle, Thanwerdas, Joël, Martinez, Adrien, Paris, Jean-Daniel, Machida, Toshinobu, Sasakawa, Motoki, Worthy, Douglas, E J, Lan, Xin, Thompson, Rona, L, Sollum, Espen, Arshinov, Mikhail
• 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), National Institute for Environmental Studies (NIES), Environment and Climate Change Canada (ECCC), Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado Boulder -National Oceanic and Atmospheric Administration (NOAA), Norsk Institutt for Luftforskning (NILU), Chercheur indépendant
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2023
• Subjects: [SDU]Sciences of the Universe [physics]; Arctic; Global warming
• Online Access: https://hal.science/hal-04134496; https://hal.science/hal-04134496/document; https://hal.science/hal-04134496/file/acp-23-6457-2023.pdf; https://doi.org/10.5194/acp-23-6457-2023

International audience The Arctic is a critical region in terms of global warming. Environmental changes are already progressing steadily in high northern latitudes, whereby, among other effects, a high potential for enhanced methane (CH 4) emissions is induced. With CH 4 being a potent greenhouse gas, additional emissions from Arctic regions may intensify global warming in the future through positive feedback. Various natural and anthropogenic sources are currently contributing to the Arctic's CH 4 budget; however, the quantification of those emissions remains challenging. Assessing the amount of CH 4 emissions in the Arctic and their contribution to the global budget still remains challenging. On the one hand, this is due to the difficulties in carrying out accurate measurements in such remote areas. Besides, large variations in the spatial distribution of methane sources and a poor understanding of the effects of ongoing changes in carbon decomposition, vegetation and hydrology also complicate the assessment. Therefore, the aim of this work is to reduce uncertainties in current bottom-up estimates of CH 4 emissions as well as soil oxidation by implementing an inverse modelling approach in order to better quantify CH 4 sources and sinks for the most recent years (2008 to 2019). More precisely, the objective is to detect occurring trends in the CH 4 emissions and potential changes in seasonal emission patterns. The implementation of the inversion included footprint simulations obtained with the atmospheric transport model FLEXPART (FLEXible PARTicle dispersion model), various emission estimates from inventories and land surface models, and data on atmospheric CH 4 concentrations from 41 surface observation sites in the Arctic nations. The results of the inversion showed that the majority of the CH 4 sources currently present in high northern latitudes are poorly constrained by the existing observation network. Therefore, conclusions on trends and changes in the seasonal cycle could not be obtained for the ...