Xiong Ying, Kort Eric A, Bloom A Anthony, Gerlein-Safdi Cynthia, Pu Tianjiao, Bilir Eren
Department of Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, MI USA.
Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA USA.
Commun Earth Environ. 2025;6(1):450. doi: 10.1038/s43247-025-02438-3. Epub 2025 Jun 10.
Atmospheric methane is rapidly increasing, and the role of tropical wetlands in the global methane budget raises concerns about a potential climate-wetland-methane feedback. Here we use Cyclone Global Navigation Satellite System observations to map monthly inundation dynamics across the tropics (37.4°S to 37.4°N) at high resolution (0.01° × 0.01°) over five years (2018-2023), including cloud and vegetation-covered regions. Our results reveal large seasonal and interannual variations in wetland extent not captured in traditional inundation products, with strong El Niño-Southern Oscillation correlations. Tropical wetland models driven by these inundation observations, independent precipitation products, or constrained by total water observations do not show growth in wetland methane emissions from 2020-2022. This suggests the 2020-2022 growth in methane is best explained by other methane source or sink mechanisms, or that non-hydrological controls are more important in tropical wetland methane emissions than currently understood.
大气中的甲烷正在迅速增加，热带湿地在全球甲烷收支中的作用引发了人们对潜在的气候 - 湿地 - 甲烷反馈的担忧。在此，我们利用热带气旋全球导航卫星系统观测数据，在五年（2018 - 2023年）期间以高分辨率（0.01°×0.01°）绘制了热带地区（南纬37.4°至北纬37.4°）的月度淹没动态图，包括云层覆盖和植被覆盖的区域。我们的结果揭示了传统淹没产品未捕捉到的湿地范围的巨大季节性和年际变化，且与厄尔尼诺 - 南方涛动有很强的相关性。由这些淹没观测数据、独立降水产品驱动或受总水量观测约束的热带湿地模型并未显示出2020 - 2022年湿地甲烷排放量的增长。这表明2020 - 2022年甲烷的增长最好由其他甲烷源或汇机制来解释，或者非水文控制在热带湿地甲烷排放中比目前所理解的更为重要。
