Reducing cost and improving the accuracy of radiometric sensor calibrations: Terrestrial and space

In the background are white clouds and a blue sky and set against these are the words “CO₂” with the “O” represented by the planet Earth

From the 1960s to mid-2020s, the annual global emission of carbon dioxide more than tripled. Whilst nations compile inventories on the amounts they produce, contributions can be missed. Measurements from space can give a secondary estimate, precisely track the movement of this potent greenhouse gas, and inform on how it interacts with the wider climate system. To do this requires accurate satellite instruments, verified by metrology.

Challenge

Solution

Impact

Image showing polar bear on ice sheet

Metrology for SI traceable climate observations

Over half of the 55 Essential Climate Variables, used to predict how the Earth’s climate is evolving, has a space-based contribution. The MetEOC series of projects: • MetEOC (2011-2014) improved NMI calibration facilities, including ones used to calibrate instruments in the field. • MetEOC-2 (2014–2017) improved performance of an originally lab-based cryogenic solar radiometer to enable improvements of measurements of incoming solar radiation by a factor of 10 and developed standards and instrumentation for the characterisation of large areas of ocean, vegetation and desert, used to confirm satellite-borne instrumentation performance. • MetEOC-3 (2017-2021) integrated tuneable laser methods into calibration facilities such as STAR, to allow enhanced calibrations of spectroscopic instruments, for example, to retrieve localised measurements of CO₂. • MetEOC-4 (2020-2023) further improved the accuracy of calibration facilities, developing new instrumentation and standards to allow more comparable data on sky radiance from ground-based networks. These results will provide trustworthy evidence to policy makers and help timely and measured mitigation strategies to be implemented.

  • Link to PROJECT Metrology to establish an SI traceable climate observing system
  • Contact: Nigel Fox
  • NPL | +44 20 8943 6825 | nigel.fox@npl.co.uk
  • Category
  • Environment,
  • EMN Climate and Ocean Observation,