Leveraging ICOS Data for Inverse Modelling of Greenhouse Gas Fluxes within ITMS

The European atmospheric ICOS dataset of anthropogenic greenhouse gases (CO₂, CH₄ and N₂O) is a critical component of ITMS inverse models, forming the backbone for reliable emission estimates, reducing uncertainties, and supporting climate research and policy. The data are publicly available at different quality levels and time resolutions, with the shortest latency of 24 hours.

Figure 1. Locations of ICOS Atmosphere stations. Source: www.icos-cp.eu/observations/atmosphere/stations

Figure 1. Locations of ICOS Atmosphere stations. Source: www.icos-cp.eu/observations/atmosphere/stations

The Integrated Carbon Observation System (ICOS) is the European research infrastructure for monitoring, quantifying, and understanding the carbon balance. It provides an essential dataset for climate research, offering high-quality, standardised measurements of greenhouse gases. These observations are crucial for the ITMS inverse models, enabling the independent verification of greenhouse gas emissions reported to the NIR (National Inventory Report) under UNFCCC. Established in 2015, ICOS delivers atmospheric data for CO₂, CH₄ and N₂O in three products: Near-real-time data within 24 hours with automatic quality control; Fast Track data within 3 months with manual PI control; and the highest-quality Level 2 product annually. All datasets are openly available under the FAIR (Findable, Accessible, Interoperable, and Reusable) principles.

Figure 2. Time series of methane at German tall tower stations and European background station Mace Head, Ireland. Source: www.dwd.de/icos und Lan, X. et al: Atmospheric Methane Dry Air Mole Fractions from the NOAA GML Global Greenhouse Gas Reference Network, Carbon Cycle Cooperative Global Air Sampling Network: 1983 - Present, Version: 2025-08-15, https://doi.org/10.15138/VNCZ-M766

Figure 2. Time series of methane at German tall tower stations and European background station Mace Head, Ireland. Source: www.dwd.de/icos und Lan, X. et al: Atmospheric Methane Dry Air Mole Fractions from the NOAA GML Global Greenhouse Gas Reference Network, Carbon Cycle Cooperative Global Air Sampling Network: 1983 - Present, Version: 2025-08-15, https://doi.org/10.15138/VNCZ-M766

ICOS data are available through the ICOS Carbon Portal: https://www.icos-cp.eu/observations/carbon-portal

Further information on the German ICOS network: https://www.icos-infrastruktur.de/en/