Decreasing seasonal cycle amplitude of methane in the northern high latitudes being driven by lower-latitude changes in emissions and transport

Dowd, Emily; Wilson, Chris; Chipperfield, Martyn P.; Gloor, Emanuel; Manning, Alistair; Doherty, Ruth

doi:https://doi.org/10.5194/acp-23-7363-2023

Articles | Volume 23, issue 13

https://doi.org/10.5194/acp-23-7363-2023

© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/acp-23-7363-2023

© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 23, issue 13

Research article

|

05 Jul 2023

Research article |

| 05 Jul 2023

Decreasing seasonal cycle amplitude of methane in the northern high latitudes being driven by lower-latitude changes in emissions and transport

Emily Dowd, Chris Wilson, Martyn P. Chipperfield, Emanuel Gloor, Alistair Manning, and Ruth Doherty

Supplement

https://doi.org/10.5194/acp-23-7363-2023-supplement

Data sets

Atmospheric Methane Dry Air Mole Fractions from the NOAA GML Carbon Cycle Cooperative Global Air Sampling Network, 1983-2020, Version: 2021-07-30 E. Dlugokencky, A. Crotwell, J. Mund, M. Crotwell, and K. Thoning https://doi.org/10.15138/VNCZ-M766

History of chemically and radiatively important atmospheric gases from the Advanced Global Atmospheric Gases Experiment (AGAGE) R. Prinn, R. Weiss, J. Arduini, T. Arnold, H. DeWitt, P. Fraser, A. Ganesan, J. Gasore, C. Harth, O. Hermansen, J. Kim, P. Krummel, S. Li, Z. Loh, C. Lunder, M. Maione, A. Manning, B. Miller, B. Mitrevski, J. Muhle, S. O'Doherty, S. Park, S. Reimann, M. Rigby, T. Saito, P. Salameh, R. Schmidt, P. Simmonds, L. Steele, M. Vollmer, H. J. Wang, B. Yao, Y. Yokouchi, D. Young, and L. Zhou https://doi.org/10.3334/CDIAC/ATG.DB1001

Decreasing seasonal cycle amplitude of methane in the northern high latitudes being driven by lower latitude changes in emissions and transport E. Dowd, C. Wilson, M. Chipperfield, E. Gloor, A. Manning, and R. Doherty https://doi.org/10.5281/zenodo.7997653

Continuous Observational Data of Atmospheric CH4 Mixing Ratios on Hateruma Island Y. Tohjima https://doi.org/10.17595/20160901.003

Continuous Observational Data of Atmospheric CH4 Mixing Ratios at Cape Ochi-ishi Y. Tohjima https://doi.org/10.17595/20160901.004

Global fire emissions estimates during 1997–2016 (https://www.geo.vu.nl/~gwerf/GFED/GFED4/tables/GFED4.1s_CH4.txt) G. R. van der Werf, J. T. Randerson, L. Giglio, T. T. van Leeuwen, Y. Chen, B. M. Rogers, M. Mu, M. J. E. van Marle, D. C. Morton, G. J. Collatz, R. J. Yokelson, and P. S. Kasibhatla https://doi.org/10.5194/essd-9-697-2017

Model code and software

Atmospheric carbon dioxide at Mauna Loa Observatory: 2. Analysis of the NOAA GMCC data, 1974–1985 (https://gml.noaa.gov/aftp/user/thoning/ccgcrv/) K. W. Thoning, P. P. Tans, and W. D. Komhyr https://doi.org/10.1029/JD094iD06p08549

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Short summary

Surface observations of methane show that the seasonal cycle amplitude (SCA) of methane is decreasing in the northern high latitudes (NHLs) but increased globally (1995–2020). The NHL decrease is counterintuitive, as we expect the SCA to increase with increasing concentrations. We use a chemical transport model to investigate changes in SCA in the NHLs. We find well-mixed methane and changes in emissions from Canada, the Middle East, and Europe are the largest contributors to the SCA in NHLs.