Long-term and interannual variations of atmospheric methane observed by the NIES and collaborative observation networks

作者：Taku Umezawa, Yasunori Tohjima, Yukio Terao, Motoki Sasakawa, Astrid Müller, Tazu Saeki, Toshinobu Machida, Shin‐Ichiro Nakaoka, Hideki Nara, Shohei Nomura, Masahide Nishihashi, Hitoshi Mukai, Matthias Frey, Isamu Morino, Hirofumi Ohyama, Yukio Yoshida, Jiye Zeng, Hibiki Noda, Makoto Saito, Tsuneo Matsunaga, T. Sugita, Hiroshi Tanimoto, Yosuke Niwa, Akihiko Ito, Y. Yamashita, Tomoko Shirai, Misa Ishizawa, Kentaro Ishijima, Kazuhiro Tsuboi, Yousuke Sawa, Hidekazu Matsueda · 发表于：Progress in Earth and Planetary Science · 年份：2025 · DOI：10.1186/s40645-025-00711-9 · 被引用次数：4 · 研究领域：Atmospheric and Environmental Gas Dynamics、Atmospheric Ozone and Climate、Atmospheric chemistry and aerosols

Abstract Effective action for climate change mitigation requires an accurate understanding of global greenhouse gas budgets, including those of methane (CH 4 ). Atmospheric measurement data provide key constraints for estimating the magnitudes and distributions of sources and sinks and are utilized in atmospheric chemistry transport modeling studies. Long-term atmospheric measurement networks have revealed decadal, interannual, and seasonal variations in atmospheric CH 4 . In 2020, a record-breaking annual CH 4 increase was recorded, but its cause is still unknown. This study analyzes atmospheric CH 4 variations using data from the National Institute for Environmental Studies (NIES) and its collaborative observation networks. Datasets from ground, mobile, and satellite platforms, employing diverse measurement techniques, confirmed past episodes, recent remarkable increases, and spatial distributions of atmospheric CH 4 . Our data clearly showed a sustained CH 4 increase from 2020 to 2022, with the highest annual increase in 2021. The atmospheric CH 4 increase was pronounced in the northern mid-to-high latitudes in 2020, but the enhancement shifted south in 2021 and 2022. This study demonstrates the capability of observational data from the NIES and collaborative networks in accurately characterizing spatiotemporal variations in atmospheric CH 4 regularly, supporting the improvement of our estimates of the global CH 4 budget.