To tackle the challenges of an integrated support capacity on a global scale, it is paramount to identify the complementarity between observations, modelling and data assimilation methodologies by establishing their limitations and strengths. CHE will address these aspects in four work packages (WP1 - WP4) that will use existing capabilities to provide supportive datasets and assessments of the current state of affairs, while at the same time bringing innovation to the various components with an eye on overall integration in a fully comprehensive system (Scientific Layer). In addition, CHE will identify the operational aspects of all the components to ensure a realistic architecture (WP5).

Together with the capacity-building aspects (WP6) and coordination (WP7), this is summarized in Figure 3, with a work breakdown structure that illustrates the seven CHE work packages interconnected and clustered in layers. The work packages are described in the next section.

The programmatic core of the project is interlinked with the European Commission Task Forces on CO₂ and provides the vision and the key science questions. A science and data compilation layer, which consists of four work packages, aims to provide research-based answers and to propose solutions to the CHE monitoring challenges. The outer layer is the service element, where the proposed research solutions from WP1-WP4 are tested for feasibility, adapted, and integrated into an application-oriented system. The activities within this layer are expected to benefit from a strong connection to certain users of the environmental monitoring products under the Copernicus umbrella.

Schematic representation of the CHE capacity building shell: a programmatic core, a science layer, a service element layer.

The CHE project has been designed to address the four main topics of the EO-3-2017 Call requirements in corresponding scientific work packages (Scientific layer). In addition, there are three work packages that focus on operational aspects of a future monitoring capacity, community building and interaction with related international efforts, and project coordination and outreach.

 

Relationship of Work Packages

WP1 (Coordinating Efforts on Reconciling top-down and bottom-up estimates) will address the current inconsistencies between satellite-based and in-situ based inversions, also in comparison with bottom-up estimates. The work package will gather and create multiple relevant satellite remote-sensing datasets and use them in developing data assimilation systems to specifically address four challenges: (i) optimally integrate satellite retrieval bias-correction into the data assimilation processing chain; (ii) minimize the impact of transport model errors on surface flux estimates; (iii) improve the model-data fusion techniques for joint natural and anthropogenic CO₂ emission estimates; (iv) deploy more advanced surface flux descriptions of natural and anthropogenic CO₂ emissions in the data assimilation chain. Easy and fast benchmarking of the outcomes of these systems will enable rapid innovation and the outcomes will be used at the end of the project to identify and outline developments towards a future data assimilation system that uses space-based remote sensing products.

WP2 (Coordinating Efforts on Library of simulations for emissions and atmospheric transport) will generate a library of realistic CO₂ simulations for present-day and future emission scenarios, “nature runs”, from the global to the regional scale to serve as input for other WPs. In a wider framework, they will also support the assessment of the requirements for a future space mission and the challenges introduced by the issues listed above. The model simulations will be based on current and future emission scenarios and cover a range of scales, from 1 km for a regional domain to 10 km for a global domain. In addition, specific simulations for point sources at sub-kilometre scale will be provided.

WP3 (Coordinating Efforts on Uncertainty trade-off for fossil fuel emissions) will evaluate the current status and possible improvements from enhanced space-borne and in-situ observation scenarios for quantifying fossil fuel CO₂ emissions. This will be based on Observation System Simulation Experiments (OSSEs) and Quantitative Network Design (QND) studies using different approaches (high-resolution inverse transport modelling of CO₂ and co-emitted species, advanced carbon cycle-fossil fuel data assimilation systems integrating CO₂, radiocarbon, terrestrial and socioeconomic datasets). For the inverse modelling and data assimilation systems, prior anthropogenic emissions and their uncertainties are needed. In addition, the transport model inversions also require high-resolution prior biogenic fluxes with quantified uncertainties. Based on these experiments the WP will report on a set of integrated monitoring strategies that blend bottom-up and top-down approaches for estimating fossil CO₂ emissions.

WP4 (Coordinating Efforts on Attributing CO₂ emissions from in-situ measurements) will explore the practical implications of distinguishing between anthropogenic and biogenic CO₂ fluxes. It is dedicated to optimising the space-time sampling of 14C, Carbon Monoxide and Atmospheric Potential Oxygen (APO, a tracer based on the atmospheric mixing ratio of O₂ with a correction for the influence of land biosphere photosynthesis and respiration, Stephens et al., 1998). The attribution problem will be addressed with an ensemble of five forward and inverse modelling tools, again providing a representative cross-section of current methodologies. They will be applied to a series of hypothetical in-situ networks with varying spatial and temporal density to evaluate their capability to extract the signal from anthropogenic emissions within the domain. As a preparatory step, the current European in-situ observation network for measurements of atmospheric mixing ratios of CO₂, CO, 14C-CO₂, and APO will be surveyed and documented.

WP5 (Towards a Prototype of a European anthropogenic emission monitoring system), will integrate the research components from WP1 to WP4 with the aim of probing the elements of a future operational support capacity. It will rely on results from the scientific work packages using a diversity of approaches to explore the different critical elements for the monitoring system, namely: bottom-up national inventories; value of observational infrastructure; and value of models and data assimilation algorithms. The exploration of the potential combination and synergy of the different approaches will guide the design of the components for a future operational prototype. Service element requirements for the future anthropogenic CO₂ emission monitoring system will be assessed in terms of timeliness, cost/efficiency, maintenance/robustness and crucially the ability to achieve target accuracy of both the emissions themselves and their trends over many years.

WP6 (International Stakeholder Coordination and Liaison) will initiate and maintain the liaison with the European Commission, ESA, Task Forces A and B and other stakeholders, such as Copernicus services, GCOS, GAW, IG3IS, CEOS/CGMS, GEO, WIGOS, and UNFCCC. In addition, CHE will seek input from stakeholders from the user community, such as the European Commission and national inventory builders. It will organise workshops to discuss elements of the CO₂ emission monitoring system with the wider community and coordinate with international collaborations and existing or upcoming project initiatives. WP6 will raise awareness of the work performed and documented in WP1-5, sharing it beyond the CHE consortium and with key stakeholders.

WP7 (Project Management, Dissemination and Communication) will ensure the CHE project is coordinated and project managed in a timely and effective manner. It covers the administrative and financial support and will apply established quality management methods. WP7 will also look after communication and dissemination of the project outcomes from WP1-6.