Quality-assured satellite data are of central interest to the QA4ECV project. Satellites have revolutionised the Earth’s observation system of climate change and air quality over the past three decades, providing continuous data covering the entire Earth. However, many users of these data are not conscious of the quality of these satellite data. Because of this, the European Union expressed in its 2013 6th FP7 Space Research Call a need for reliable, traceable, and understandable quality information on satellite data records that could serve as a blueprint contribution to a future Copernicus Climate Change Service. QA4ECV runs from January 2014 until December 2017.

The potential of satellite data to benefit climate change and air quality services is too great to be ignored. QA4ECV therefore attempts to bridge the gap between end-users of satellite data and the satellite data products. We are developing an internationally acceptable Quality Assurance (QA) framework that provides understandable and traceable quality information for satellite data used in currently evolving climate and air quality services. Such a framework should deliver the historically linked long-term data sets that users need, in a format that they can readily use.

As a demonstration of its capacity, QA4ECV will generate multi-decadal climate data records for 3 atmospheric ECV precursors (nitrogen dioxide, formaldehyde, and carbon monoxide) and 3 land ECVs (albedo, leaf area index and absorbed photosynthetically active radiation), with full uncertainty metrics for each and every satellite measurement. Multi-use tools and SI/community reference standards will also be developed. But QA4ECV is not only about satellites. It is also about exploiting independent reference data obtained from in situ networks, and applying these data with the right, traceable methodologies for quality assurance of the satellite ECVs.