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

Umezawa, Taku; Tohjima, Yasunori; Terao, Yukio; Sasakawa, Motoki; Müller, Astrid; Saeki, Tazu; Machida, Toshinobu; Nakaoka, Shin-Ichiro; Nara, Hideki; Nomura, Shohei; Nishihashi, Masahide; Mukai, Hitoshi; Frey, Matthias Max; Morino, Isamu; Ohyama, Hirofumi; Yoshida, Yukio; Zeng, Jiye; Noda, Hibiki; Saito, Makoto; Matsunaga, Tsuneo; Sugita, Takafumi; Tanimoto, Hiroshi; Niwa, Yosuke; Ito, Akihiko; Yamashita, Yousuke; Shirai, Tomoko; Ishizawa, Misa; Ishijima, Kentaro; Tsuboi, Kazuhiro; Sawa, Yousuke; Matsueda, Hidekazu

doi:10.1186/s40645-025-00711-9

Fig. 2

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

Temporal variations in a atmospheric CH₄ mole fractions and b growth rates at COI (blue symbols) and HAT (red symbols). Each symbol represents monthly mean values. The light blue and pink lines in the top panel indicate the deseasonalized trend curves, which were used to calculate the instantaneous growth rates (bottom panel)

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