The overall aim of the project is to contribute to the establishment of the necessary metrology infrastructure, tailored to climate needs in readiness for its use in climate observing systems. The project is broken down into 4 technical work packages:

Work package 1: Traceability and interoperability for remotely sensed optical ‘level-1’ data

  • Spectrally selective pre-flight calibration of Earth observation sensors
    • Two new facilities for tuneable-laser based satellite sensor calibration, one for cubesats and the other designed to be portable, cleanroom compatible (0.5-2%) and suitable for spectroscopic sensors.
  • Rigorous pixel-level uncertainty and covariance analysis of satellite and airborne sensor products
    • Detailed uncertainty analysis for EO sensors, providing pixel level uncertainty and covariance information from first-principles analysis.
  • International references for satellite level-1 product comparison and validation
    • Methods for validating and comparing satellite level-1 products using ‘accessible’ and ‘remote’ reference test sites. Modelling site spectral BRDF properties, initiating community metrological radiative transfer code and providing recommendations to CEOS for international standardisation.

Work package 2: Traceability of atmospheric ECV products

Improve the traceability and further reduce the measurement uncertainties of atmospheric ECVs by interlocked and complementary means.

  • Develop new reference instruments based on spatial heterodyne spectrometers (SHS) for the ground-based Network for the Detection of Mesospheric Change (NDMC).
  • Enable detection of anthropogenic induced temperature changes of 1K per decade through emission from OH and O radicals
  • Develop a CubeSat based SHS and traceability concept to extend NDMC to global coverage.
  • Verify new approach used for the non-uniformity correction of array detectors to IR hyperspectral imagers, potentially reducing the effect by an order of magnitude.

Work package 3: Facilitating traceable evaluation of satellite derived biophysical ECV products through in-situ, airborne and satellites

Validation of satellite-derived biophysical ECVs (Land and Ocean) requires comparison with ‘ground-truth’ or products from independent EO missions. However, the target quantity is rarely measured directly, requiring a retrieval algorithm and in-situ sampling that is not representative of the satellite observation (e.g. spatial scale)

  • Quantifying biases/uncertainties in end-to-end validation (ground and satellite) of fAPAR
  • Establishing SI-traceable tools and methods (Lidar, UAV, sensor networks and computer simulations) utilising explicit reconstructions of forest test-sites
  • Design and test prototype hyperspectral radiometer for System Vicarious Calibration (SVC) of Ocean colour (OC) sensors like OLCI (Sentinel 3) for lake, coastal and ocean applications.
  • Rigorous end-to-end GUM based uncertainty analysis for European SVC OC infrastructure (target <2 %)

Work package 4: Traceability of Radiation ECVs

Replace WMO community based scales with SI Traceability

  • Establish traceability to World Infrared Standard Group (WISG) (sky radiance) of WMO BSRN network reducing uncertainty from 5 to 2 Wm-2.
    • Design and build novel prototype Black body for calibration of hemispherical detecting radiometers
    • IR spectral responsivity 1 to 50 µm
  • Identify source of anomaly between different WISG radiometer types
  • Upgrade the Cryogenic Solar Absolute Radiometer (CSAR) (SI solar radiometer) to operate in ‘active mode’ including electronics to allow full autonomous operational measurements (ground and space) at target uncertainty of 0.02%
  • Evidence to support candidature to allow CSAR to become SI replacement of WMO WRR