Anthropogenic methane emissions from urban centers are important and addressable, yet remain poorly characterized, and the representativeness of studies from individual cities is unknown. A satellite-based approach provides a pathway to tackle this challenge on a national or global scale. Here we present a space-based method that uses the simultaneous, daily observation of methane and carbon monoxide from the TROPOMI satellite to estimate urban methane emissions. We assess and validate the method and demonstrate that using these simultaneous observations enables robust assessment of methane emissions from urban centers without relying on atmospheric transport models. Initial assessments with this approach in eight United States cities suggest emission inventory underestimates previously discovered in older East Coast cities are more broadly representative, with aggregated emissions totaling 1.47 (0.56, 3.19, 95% confidence interval) Tg CH₄/year, compared to the Environmental Protection Agency estimate of 0.52 Tg CH₄/year. We show this data driven approach provides a pathway to study urban methane emissions across the globe and track how emissions respond if urban mitigation measures are implemented by investigating three additional megacities outside the United States.

来自城市中心的人为甲烷排放很重要且可寻址，但仍然缺乏表征，个别城市研究的代表性未知。基于卫星的方法提供了在国家或全球范围内应对这一挑战的途径。在这里，我们提出了一种基于空间的方法，该方法使用来自 TROPOMI 卫星的每日同步观测甲烷和一氧化碳来估算城市甲烷排放量。我们评估和验证了该方法，并证明使用这些同步观测可以在不依赖大气传输模型的情况下对城市中心的甲烷排放进行稳健评估。₄ /年，而环境保护署估计的 0.52 Tg CH ₄ /年。我们展示了这种数据驱动的方法提供了一种研究全球城市甲烷排放的途径，并通过调查美国以外的另外三个特大城市来跟踪如果实施城市缓解措施，排放将如何响应。