The Metrology for Earth Observation and Climate project - MetEOC-2 - provides the data needed to underpin climate change research and its impacts, (e.g. flooding and agriculture), and can quantify environmental issues such as pollution and coastal erosion. Satellite data can also be used to detect subtle changes in Essential Climate Variables. For example, changes in total solar energy and sea surface temperatures of a few tenths of a per cent per decade can be detected in this way. However, the performance of satellite instruments is prone to degradation post-launch and from exposure to the harsh environmental conditions above the atmosphere. So, to guarantee data reliability, these instruments generally need re-calibrating and validating in orbit.

Calibration against, and traceability to, the international system of units (SI) would guarantee long-term confidence, accuracy and reliability of such data and ensure consistency between instruments.

These basic data products are additionally processed through complex non-linear retrieval algorithms to obtain the geophysical and biophysical parameters (e.g. the ECVs) that are important for understanding the state of the planet. End-to-end assessment of uncertainty and traceability was recognised as a challenge worth addressing by the climate community with support from metrology experts

This project was funded by grant number ENV55 within the European Metrology Research Programme (EMRP)