Dual-comb spectroscopy (DCS) provides broadband, high-resolution, high-sensitivity amplitude and phase spectra within a short measurement time, thus holding promises for atmospheric spectroscopy. However, previous research has been limited to measuring over open-air paths of about 20 km. Here, by developing a bistatic set-up using time–frequency dissemination and high-power optical frequency combs, we implement DCS over a 113 km turbulent horizontal open-air path. We successfully measure the absorbance spectra of CO₂ and H₂O with a 7 nm spectral bandwidth and a 10 kHz frequency accuracy, and achieve a sensing precision of <2 ppm in 5 min and <0.6 ppm in 36 min for CO₂. We anticipate our system to find immediate applications in the monitoring of urban greenhouse gas and gaseous pollutants emission. Our technology may also be extended to satellite-based DCS for greenhouse gas monitoring and calibration measurements.

双梳光谱（DCS）在短时间内提供宽带、高分辨率、高灵敏度的振幅和相位光谱，从而为大气光谱带来了希望。然而，之前的研究仅限于测量约 20 公里的露天路径。在这里，通过开发使用时频传播和高功率光学频率梳的双基地装置，我们在 113 公里的湍流水平露天路径上实施 DCS。我们成功测量了 CO ₂和 H ₂ O 的吸收光谱，光谱带宽为 7 nm，频率精度为 10 kHz，CO ₂的传感精度在 5 分钟内达到 <2 ppm，在 36 分钟内达到 <0.6 ppm 。我们预计我们的系统将立即应用于监测城市温室气体和气态污染物排放。我们的技术还可以扩展到基于卫星的 DCS，用于温室气体监测和校准测量。