Space-based Recording of Intensive Gas Seeps on the Sea Surface due to Damage to the Nord Stream 1 and Nord Stream 2 Gas Pipelines

Anomalously intensive gas seeps on the sea surface due to damage to the Nord Stream 1 and Nord Stream 2 subsea gas pipelines in the Baltic Sea have been analyzed using optical (Kanopus-V and Sentinel-2B) and radar (Sentinel-1A) satellite images. Positive contrasts of NRCS (up to 7.5 dB) registered by Sentinel-1A radar and of spectral reflectance (up to 0.73 units) registered by Kanopus-V and Sentinel-2B optical sensors have been detected in the area of the gas seeps. Specific features of the seeps were revealed on the sea surface in the form of dome-shaped swells, fountains, vortices, foam, wave breaking, disturbance of the surface wave structure, and wind shadows. Taking into consideration the volume and density of gas located in the damaged gas pipelines, it was shown that the total volume of methane emission was no more than ~0.51 Tg, i.e., less than 0.1% of the annual global methane emissions into the atmosphere.