Ship-borne measurements of atmospheric CH4 concentration and 𝜹13C-CH4 after the Nord Stream 2 detonation in October 2022

The time series of the atmospheric CH4 concentration and 𝜹13C-CH4 were measured continuously during the nights from the third to the sixth of October with a Picarro G2132-i Isotope Analyser. For this, air was sucked from the deck of the research vessel Skagerak at about 12 m above water surface using a Teflon tube. A constant flow rate was generated with a Boxer 3KQ Diaphragma Pump. The Picarro G2132-i then continuously measured on the "High Precision" mode with 3 Hz. Spatial and temporal CH4 concentration differences with higher atmospheric CH4 concentrations closer to the Leaks were recorded. The measured peak in the atmospheric CH4 concentration on October 5th is related to a shift in 𝜹13C-CH4 being relatively more enriched in 13C compared to the background signal. The wind is mainly blowing from the south-west during this period indicating a direct influence by the Nord Stream leaks. This is reflected by the shift towards a heavier isotopic signature showing the influence from the natural gas emitted from the Nord Stream leaks.