Remedy 1: Improved characterisation of high quality instrumentation to increase the pool of reference quality observing techniques without necessitating new observational deployments

Work to substantially improve the breadth of existing measurement techniques and programs that can be considered truly reference quality measurement systems. Building upon foundational work in existing EU H2020 projects such as QA4ECV, GAIA-CLIM, and FIDUCEO and by other international activities such as METEOMET, GRUAN, NDACC, GAW, the ESA Fiducial Reference Measurements program, etc. Undertake to improve the metrological characterisation of present and planned non-satellite measurement techniques for a broad range of atmospheric, oceanic, and terrestrial ECVs. Necessary steps include:

• Full characterisation of the processing chain for each individual measurement technique considered;

• Establishing traceability to SI or community standards;

• Quantifying the uncertainty in each processing step with metrological rigor;
• Ensuring comparability through necessary standardisation of techniques;

• Documentation of final product via the peer-reviewed literature and associated documentation.

This work shall require the involvement of instrument experts, metrologists, and potential end-users. The remedy should involve those measurement networks, which may deploy the developed measurement techniques as key partners to ensure uptake of the newly developed measurement streams in the field.