Periodic Reporting for period 1 - EYE-CLIMA (Verifying Emissions of Climate Forcers)
Période du rapport: 2023-01-01 au 2024-06-30
The Global Stocktake, and thus the success of the Paris Agreement, hinges on the information nations provide about their emissions through National Greenhouse Gas Inventories (NGHGIs). Current methodologies laid-out by the IPCC for reporting emissions are generally built around the use of economic activity data and emission factors. Although they are designed to be transparent, they can have significant uncertainties owing to incomplete or inaccurate information, as well as due to approximations inherent to the emission factor approach. The 2019 refinement of the IPCC Guidelines recognises the need for independent verification of NGHGIs, especially using atmospheric observations. However, the technical complexity and the hitherto limited resolving power of atmospheric constraints makes it challenging for NGHGI compilers to adopt this type of verification.
EYE-CLIMA will address this need for independent verification by developing observation-based methods (using both satellite remote sensing and ground-based observations) to a level of readiness where they can be used to determine emissions at national and sub-national scales and for verification of NGHGIs. The methodology involves using process-based and data-driven models to simulate GHG fluxes, first without atmospheric observations. These fluxes are then combined with models of atmospheric transport and chemistry to assimilate atmospheric observations, which are used to correct the first flux estimates. This latter approach is referred to as the “atmospheric inversion” method. EYE-CLIMA will have a strong focus on improving the atmospheric inversion method, and better quantifying the uncertainties in the emissions derived this way, in order to increase the reliability and utility of the approach.
Through engagement with stakeholders, i.e. NGHGI compilers, EYE-CLIMA, will develop flux data products for CO2 (LULUCF sector), CH4, N2O, and emissions data of F-gases (SF6, HFC-23, HFC-143a, HFC-125, HFC-134a, HFC-32) and black carbon (BC), which will be tailored to their needs. The emissions of CH4 and BC will be attributed to natural versus anthropogenic sources, and for the latter, to broad source sectors that can be compared with groups of IPCC sectors used in NGHGIs. The methodology for the atmospheric inversions and how to use these for verification of NGHGIs will be described in good practice guidelines. The aim of these guidelines is to provide a reference (especially for NGHGI compilers who are interested in running their own atmospheric inversions) on how to set-up atmospheric inversions in order to minimise errors, as well as how to use atmospheric inversion data to compare with NGHGIs. In addition, EYE-CLIMA will develop code to that could be used by NGHGI compilers to check their inventory estimates against atmospheric inversion estimates.
EYE-CLIMA will address this need for independent verification by developing observation-based methods (using both satellite remote sensing and ground-based observations) to a level of readiness where they can be used to determine emissions at national and sub-national scales and for verification of NGHGIs. The methodology involves using process-based and data-driven models to simulate GHG fluxes, first without atmospheric observations. These fluxes are then combined with models of atmospheric transport and chemistry to assimilate atmospheric observations, which are used to correct the first flux estimates. This latter approach is referred to as the “atmospheric inversion” method. EYE-CLIMA will have a strong focus on improving the atmospheric inversion method, and better quantifying the uncertainties in the emissions derived this way, in order to increase the reliability and utility of the approach.
Through engagement with stakeholders, i.e. NGHGI compilers, EYE-CLIMA, will develop flux data products for CO2 (LULUCF sector), CH4, N2O, and emissions data of F-gases (SF6, HFC-23, HFC-143a, HFC-125, HFC-134a, HFC-32) and black carbon (BC), which will be tailored to their needs. The emissions of CH4 and BC will be attributed to natural versus anthropogenic sources, and for the latter, to broad source sectors that can be compared with groups of IPCC sectors used in NGHGIs. The methodology for the atmospheric inversions and how to use these for verification of NGHGIs will be described in good practice guidelines. The aim of these guidelines is to provide a reference (especially for NGHGI compilers who are interested in running their own atmospheric inversions) on how to set-up atmospheric inversions in order to minimise errors, as well as how to use atmospheric inversion data to compare with NGHGIs. In addition, EYE-CLIMA will develop code to that could be used by NGHGI compilers to check their inventory estimates against atmospheric inversion estimates.
Towards the objective of “improving estimates of CO2 emissions and removals of CO2 in the LULUCF sector”, EYE-CLIMA has reviewed existing biomass and biomass change datasets and their suitability to be used in preparing GHG inventories or as a benchmark for reporting to the UNFCCC.
Progress has also been made towards the objective of “developing a new methodology to detect and quantify large emissions of CH4 using high resolution satellite data”. For this, EYE-CLIMA has produced a first detailed assessment of CH4 total column retrievals from the TROPOMI instrument onboard the Sentinel-5 Precursor (SP5) satellite. The assessment is made globally but with a focus over Europe. Three different CH4 retrieval products are evaluated by comparing the retrievals against ground-based reference data from the TCCON network. All three retrieval products show a high level of agreement with TCCON.
Towards the objective of “supporting the implementation and monitoring of EU policy through providing accurate estimates of GHG fluxes and black carbon emissions”, black carbon (BC) observations were harmonized and quality controlled. This process involved compiling BC observation data from 28 sites in Europe, performing quality checks and filtering, as well as bringing the data into a standardized format. Using the harmonized dataset, the BC observations were apportioned according to their emission source (wood burning versus traffic).
Also towards this objective, EYE-CLIMA has produced estimates of the major GHG fluxes (CO2, CH4 and N2O) from the land-biosphere in Europe using process-based models. The fluxes are provided at temporal resolutions of 1 hour to 1 day and at a spatial resolution of approximately 10 km for the period 2000 to 2022.
Furthermore, EYE-CLIMA has prepared estimates for anthropogenic emissions of CH4, N2O, six F-gases, and BC, using the GAINS model. For this, the GAINS model was developed to be able to spatially distribute the emissions at 0.1° and to provide estimates at annual resolution. The estimates are provided for EU27 countries plus UK, Switzerland and Norway, and cover the period 1990 to 2020.
First atmospheric inversions have been run for CO2, CH4, N2O and SF6. Inversions have been run at 0.5° resolution for CO2 and N2O and at 1° for CH4 over Europe. In addition, work is underway on inversions of CO2, CH4 and N2O at 0.2°. This higher resolution has posed a number of technical challenges. For CO2, the inversions are run using the regional atmospheric transport model, CHIMERE. At this higher resolution, however, the CHIMERE simulations were taking too long, and thus the code was adapted to run on Graphical Processing Units (GPUs). For CH4, inversions at 0.2° have been run from 2018 to 2022. For SF6, inversions have been run globally for the period 2005 to 2021 using the atmospheric transport model, FLEXPART, with a horizontal resolution of 1.0°.
Progress has also been made towards the objective of “developing a new methodology to detect and quantify large emissions of CH4 using high resolution satellite data”. For this, EYE-CLIMA has produced a first detailed assessment of CH4 total column retrievals from the TROPOMI instrument onboard the Sentinel-5 Precursor (SP5) satellite. The assessment is made globally but with a focus over Europe. Three different CH4 retrieval products are evaluated by comparing the retrievals against ground-based reference data from the TCCON network. All three retrieval products show a high level of agreement with TCCON.
Towards the objective of “supporting the implementation and monitoring of EU policy through providing accurate estimates of GHG fluxes and black carbon emissions”, black carbon (BC) observations were harmonized and quality controlled. This process involved compiling BC observation data from 28 sites in Europe, performing quality checks and filtering, as well as bringing the data into a standardized format. Using the harmonized dataset, the BC observations were apportioned according to their emission source (wood burning versus traffic).
Also towards this objective, EYE-CLIMA has produced estimates of the major GHG fluxes (CO2, CH4 and N2O) from the land-biosphere in Europe using process-based models. The fluxes are provided at temporal resolutions of 1 hour to 1 day and at a spatial resolution of approximately 10 km for the period 2000 to 2022.
Furthermore, EYE-CLIMA has prepared estimates for anthropogenic emissions of CH4, N2O, six F-gases, and BC, using the GAINS model. For this, the GAINS model was developed to be able to spatially distribute the emissions at 0.1° and to provide estimates at annual resolution. The estimates are provided for EU27 countries plus UK, Switzerland and Norway, and cover the period 1990 to 2020.
First atmospheric inversions have been run for CO2, CH4, N2O and SF6. Inversions have been run at 0.5° resolution for CO2 and N2O and at 1° for CH4 over Europe. In addition, work is underway on inversions of CO2, CH4 and N2O at 0.2°. This higher resolution has posed a number of technical challenges. For CO2, the inversions are run using the regional atmospheric transport model, CHIMERE. At this higher resolution, however, the CHIMERE simulations were taking too long, and thus the code was adapted to run on Graphical Processing Units (GPUs). For CH4, inversions at 0.2° have been run from 2018 to 2022. For SF6, inversions have been run globally for the period 2005 to 2021 using the atmospheric transport model, FLEXPART, with a horizontal resolution of 1.0°.
Already, the inversions of SF6 have shown value in identifying trends in the emissions. For example, over Europe, the inversions show a decreasing trend in SF6 from 2005 with a significant decrease after 2017, which may be attributable to the EU F-gas regulation. This demonstrates the utility of atmospheric inversions to inform about actual trends in emissions to monitor existing policy and help determine what level of emission reduction ambition may still be required.