National Physical Laboratory

Traceability of EO Data

Traceability is a method of ensuring that a measurement (even with its associated uncertainties) is an accurate representation of what it is trying to measure. In the context of satellite product generation, this means that, for each step of a processing chain, the result of that step (and the associated uncertainties) should be demonstrably linked to the output of the previous processing step. The key to traceability is therefore Step 1 in the QA process, to document all activities, i.e. inputs, procedures and outputs at each stage of the data processing chain.

Traceability is defined within the JCGM 200 (2012) International vocabulary of metrology as:

"Property of a measurement result whereby the result can be related to a reference through a documented unbroken chain of calibrations, each contributing to the measurement uncertainty."

At NPL we are working to develop traceability of in situ sensor product data and satellite-derived products through ongoing research into uncertainty analysis and propagation through processing algorithms. For example, one of the aims of QA4ECV is to understand how these elements may be enhanced in existing algorithms.


Example of a traceability chain for GlobAlbedo
Example of a traceability chain for GlobAlbedo

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