REliable Global Methane Emissions estimates in a changing world (REGAME)

In REGAME we will update chemistry transport models (FLEXPART, OsloCTM) to include the kinetic isotope effect (KIE) of methane (CH4), enabling better constraints on the CH4 budget (KIE is dependent on source/ sink).

We will update the atmospheric inversion framework FLXINVERT to include novel use of satellite CH4 fields (Sentinel 5P).

This will include significant changes to FLEXINVERT, which will also be applicable to other satellite data e.g. carbon dioxide (CO2) and improve the model capabilities to handle large data fields in general.

With these upgrades we assess CH4 emissions from the major sources (wetlands, biomass burning, anthropogenic) at the global scale using all available data (e.g. ICOS, NOAA data, data on ebas.nilu.no).

This data includes measurements from the Zeppelin Observatory in the Arctic, to Troll in Antarctica, i.e. from pole-to-pole. Our cross disciplinary team is in a unique position to assess the state of the Arctic/ Antarctic ocean CH4 reservoir.

This reservoir is currently considered a minor source but has potential for large scale disruption if emissions increase suddenly and rapidly.

We will perform measurements of CH4 over the ocean (research vessels Helmer Hanssen, Kronprins Haakon) assess temporal variability of CH4 emission from the seabed and movement through the water column (due to e.g. variable microbial activity, ocean stratification, currents and seep emission rates), with long-term (1 year) measurements at a mooring south of Svalbard (deployed for the NorEMSO project) in an area bearing gas hydrates and active CH4 seeps. Furthermore we add to the knowledge of potential seep locations by performing echo-souding surveys.

Combining insights from these temporal and spatial studies will allow a more targeted approach to assessing the ocean source in general. Specifically in REGAME we will run a regional/ Arctic inversion including these data to constrain high latitude emissions including from the ocean.