It is critical that data and derived products are easily accessible in an open manner and have associated with them an indicator of quality traceable to reference standards (preferably SI) so users can assess suitability for their applications, i.e. the ‘fitness for purpose’.
A QI shall be based on documented and quantifiable assessments of evidence demonstrating the level of traceability to internationally agreed (where possible SI) reference standards.
A Quality Indicator (QI) shall provide sufficient information to allow all users to readily evaluate the fitness for purpose of Earth observation data or derived products.
Projects that consolidated QA4EO concepts and prepared this website
Projects that contributed to the development of QA4EO framework concepts
FIDUCEO – Fidelity and uncertainty in climate data records from Earth Observations — was a H2020 project led by Reading University, that established metrological techniques for determining traceability and uncertainty information in long-term historical data records (fundamental climate data records) from which climate data records of ECVs are calculated.
The H2020 GAIA-CLIM project (2015 - 2018) aimed established sound methods for the characterisation of satellite-based Earth Observation (EO) data by surface-based and sub-orbital measurements (non-satellite measurements).
Four EMPIR MetEOC projects, led by NPL, establish metrological techniques for Earth Observation, including pre-flight calibration, post-launch on-board and vicarious calibration and the validation of higher-level products.
The National Measurement System (NMS) provides the UK with an infrastructure of laboratories that deliver world-class measurement science and technology and provide traceable and increasingly accurate standards of measurement.
Projects that applied concepts to FRMs
RadCalNet is an initiative of the Working Group on Calibration and Validation of the Committee on Earth Observation Satellites. The RadCalNet service provides satellite operators with SI-traceable Top-of-Atmosphere (TOA) spectrally-resolved reflectances to aid in the post-launch radiometric calibration and validation of optical imaging sensor data. The ACTION / ACTION-2 / ACTION-3 projects for the ESA-ESTEC supported CEOS to maintain and further develop the RadCalNet service provision of SI-traceable Top-of-Atmosphere (TOA) spectrally-resolved reflectances to satellite operators.
FRM4SOC — Fiducial Reference Measurements for Satellite Ocean Colour — with funding from ESA, was structured to provide support for evaluating and improving the state of the art in ocean colour validation through a series of comparisons under the auspices of the Committee on Earth Observation Satellites (CEOS) Working Group on Calibration & Validation and in support of the CEOS ocean colour virtual constellation.
FRM4VEG – Fiducial Reference Measurements for Vegetation — is a European Space Agency (ESA) managed project focused on establishing the protocols required for traceable in-situ measurements of vegetation-related parameters, to support the validation of Copernicus products from Sentinel-2, -3, and PROBA-V.
St3TART — Sentinel-3 Topography mission Assessment through Reference Techniques — is an 18-month project funded by the EU and ESA, and led by NOVELTIS with a consortium of 17 partners. The project aims to generalize the concept of FRM for the Copernicus Sentinel-3 Surface Topography Mission (STM) and to collect and distribute FRM data for the validation of the satellite mission over inland waters, sea ice and land ice.
Projects that applied concepts to FDRs and TDPs
FDR4ALT with funding from ESA was structured to provide support for evaluating and improving the state of the art in ocean colour validation through a series of comparisons under the auspices of the Committee on Earth Observation Satellites (CEOS) Working Group on Calibration & Validation and in support of the CEOS ocean colour virtual constellation.
FDR4ATMOS — Developed a FDR for GOME & SCIAMACHY and Improving SCIAMACHY Data. SCIAMACHY (SCanning Imaging Absorption SpectroMeter for Atmospheric CHartographY; Greek: σκιάμάχη: analogously: "Fighting shadows") was one of ten instruments aboard of ESA's ENVIronmental SATellite, ENVISAT. The Global Ozone Monitoring Experiment (GOME) instrument was an atmospheric chemistry sensor onboard the second European Remote Sensing satellite (ERS-2, 1995 - 2011).
ASELSU — ASSESSMENT SEA LEVEL RISE STABILITY UNCERTAINTY - EXPRO+ — studies feasibility of the Sentinel-6 Next Generation space component to address new requirements by a full assessment of the Sentinel-6 Sea Level Rise Uncertainty Stability Budget using metrological best practices and procedures.
C3S 311c Lot 1: Satellite Data Rescue — Reading and NPL led project to rescue satellite data from the 1960s through the 1970s (multiple sensors) plus data from the SSU sensor (1980s-2000s). Provides quality assessments and improvements with an assessment of the data with a bias adjustment model.
Quality control projects
QA4ECV was initiated in 2014 to demonstrate how reliable and traceable quality information can be provided for satellite and ground-based measurements of climate and air quality parameters. The project developed and applied a Quality Assurance framework on new and improved multi-decadal data records of the Land ECVs Albedo, Leaf Area Index (LAI), and Fraction of Absorbed Photosynthetically Active Radiation (FAPAR), and of the Atmosphere ECVs nitrogen dioxide (NO2), formaldehyde (HCHO), and carbon monoxide (CO).
C3S_51_Lot 2_NPL — Evaluation and Quality Control for observational datasets within the C3S climate data store. Set a framework for the evaluation and quality control assessment of observations to be included in the C3S climate data store.
This website and the metrological principles documents it hosts were developed in the frame of the Instrument Data Quality Evaluation and Assessment Service - Quality Assurance for Earth Observation (IDEAS-QA4EO) contract funded by ESA-ESRIN (n. 4000128960/19/I-NS), and builds on the work of previous projects, see Acknowledgements.