Research
Some of our key research activities in Environment and Climate Change research include providing traceable measurements for Earth Observation Instrumentation, and Support for Vicarious Calibration. This involves many collaborations, which are providing international support for our satellite mission proposal TRUTHS.
The group is also involved in developing new QA/QC procedures, in collaboration with ESA for GMES. It is also playing a lead role in efforts to establish an internationally accepted data quality strategy within the wider community through CEOS and GEO.
In recent years, there has been an increasing demand for improved accuracy and reliability of Earth Observation (EO) data, stimulated not only by our desire to understand better the workings of our planet and the cause and impact of climate change, but also because improvements in models allow us to discriminate better between data. A further driver is the increasing reliance on the combination of data from different sensors and sources (satellites, aircraft and in-situ) to establish more sophisticated data products. These will be important for 'operational services' of the future, as envisaged in initiatives such as GMES (Global Monitoring of Environment and Security) of the EU and ESA and to meet the societal themes within the overarching international framework of the Group on Earth Observation (GEO). The combination of data from different sources can only be carried out if each data set has a clear, reliable statement of uncertainties or indicator of confidence level, and that all the data processing steps from collection to distribution are fully Quality Assured.
It is also of course essential that all measurements and associated instrumentation used for any quantitative purpose in remote sensing be fully traceable to SI as part of the Quality Assurance process, as recommended by the Committee of Earth Observation Satellites (CEOS) in 2001. The Optical Technologies group has, and is, engaged in all aspects of the Traceability Chain that provides the means to quality assure EO data products.
Environment / Climate Change research
- Accurate measurements of total solar irradiance (TSI) are crucial for good climate models and the evaluation of solar cells. NPL and the Physikalisch-Meteorologisches Observatorium Davos / the World Radiation Centre of WMO (PMOD/WRC) are working on a new instrument in order to improve the accuracy of the current standard by a factor of 10.
- NPL has a long history of promoting the benefits of traceability and quality assurance and is now involved, in developing new QA/QC procedures in collaboration with ESA for GMES. It is also playing a lead role in efforts to establish an internationally accepted data quality strategy within the wider community through CEOS and GEO.
- Earth Observation satellites are the main source of global data about the Earth, it is essential that satellite performance can be validated, and in some cases calibrated, using ground targets calibrated directly by in-situ measurements and local surveys. A novel approach to this problem is being developed at NPL using a remote controlled helicopter.
- The only feasible method of obtaining global-scale data on the state of the planet is through the use of satellite sensors that can measure the solar energy reflected from the Earth’s atmosphere and surface. Much effort goes into characterising such instruments before launch. Once in orbit, post-launch calibration is vital to validate the instruments’ performance.
- The Optical Technologies group has, and is, engaged in all aspects of the Traceability Chain that provides the means to quality assure EO data products.
- The Optical Technologies group can provide a number of solutions for the earth observation community. These include the calibration, characterisation and advice for sub-systems and components for satellite instruments, “end to end” pre-launch calibration through to the calibration of instrumentation used for vicarious calibration.