5 minute read
NPL, on behalf of the European Space Agency (ESA) and the UK Space Agency (UKSA), has awarded six new ‘impact case study’ contracts to explore the additional commercial/societal benefits that the future ESA TRUTHS EarthWatch mission will provide to the UK following its launch.
These case studies were awarded following a call for ideas to complement the mission’s existing science objectives. These objectives centre around improving our ability to monitor climate change, the impact of carbon mitigation policies and facilitating comprehensive trustworthy information through enabling a harmonised space-based Earth observation system as a ‘gold standard’ calibration reference in space.
TRUTHS will continually observe the Earth, pole to pole, across the whole spectrum from the UV to Short Wave Infrared with a spatial resolution as high as 50 m. Its uniqueness is its unprecedented uncertainty, 0.3%, around 10x better than other satellite mission. In addition to its core climate objectives, TRUTHS data can be used for measurements of the oceans, land, cryosphere, atmosphere and sun, making it a highly versatile tool for many applications. Six case studies have been selected to span applications impacting land, ocean and atmosphere to illustrate this scientific, commercial and societal breadth.
- Plymouth Marine Laboratory are investigating how TRUTHS’ uncertainty will improve quality and timeliness of ‘marine ecosystem forecasts’ - like weather forecasts predicting the near-term clarity and biology/health of the ocean, particularly near coasts. Water clarity information in the forecasts, currently provided in the UK by the Met office, is used by the UK Navy for underwater operations, and is also available to other users, such as divers to assess their safety. Information about water quality is important to aquaculture e.g. fish-farming and various leisure activities. TRUTHS is expected to improve the overall reliability and extend the forward prediction confidence of these forecasts, with financial impacts on key users. This will be done through upgrading the accuracy and coherence of several different satellites to improve measurement of reflectance of the ocean and with these improved observations better constrain the model running the forecast.
- In a similar project, Pixalytics Ltd, a UK SME, will investigate how the hyper-spectral properties of TRUTHS, in addition to its low uncertainty, can result in improved Chlorophyll-a measurements (ocean colour), a critical measure of ocean health that, like land vegetation, extracts carbon dioxide from the air. These microscopic plants, called phytoplankton, are not only critical for carbon uptake, removing around a third of our emissions, but are also at the bottom of the ocean food chain, supporting fisheries. This project will align with the complementary AEROSTATS project funded through a UK ARIA program, which will use autonomous airborne platforms alongside satellites and high-resolution reanalyses to address critical observational challenges in the Greenland ocean-ice margins. The melt from the Greenland icecaps can change the flow of heat in the ocean, and ultimately, our weather patterns, resulting in a significant change in our climate.
- Gentian, another UK SME will evaluate the impact of TRUTHS in support of biodiversity, looking at distinguishing habitats and change in forest ecosystems, and also heathlands (peatland protection/restoration) as examples. Monitoring and maintenance of biodiversity has become a key environmental metric with significant financial investments, but one that by its nature is hard to evaluate without remote sensing from space. Ensuring that monies are invested soundly and reaping benefits needs trustworthy precise observations that a mission such as TRUTHS can both provide itself and enable as an anchor for other space assets.
- University of Reading are exploring how TRUTHS could improve our ability to quantify land-atmosphere interactions and ultimately assess its impact on climate/weather forecasts through constraining the UK land model JULES, which is part of the UK climate modelling infrastructure. A state-of-the-art algorithm is used to incorporate observations of reflected sunlight observed by satellites to contrain the JULES estimates of absorbed energy in vegetation; a key driver of the global carbon cycle. As with the ocean, a quarter of global carbon emissions are absorbed in plants, removing them from their heating effect in the atmosphere. But change in the reflectance of the Earth as a result of vegetation growth/decline can also impact the water/radiation balance and consequently temperature/health of the planet in detrimental ways. Similar software models are used to assess health and yield of agricultural crops to support short/long-term food security planning for both farmers, policy makers and the intermediate farm to fork delivery chain in addition to the impact on the carbon budget.
- Universities of Southampton and Edinburgh are quantifying how TRUTHS can enable more reliable and accurate information through harmonisation and performance enhancement of a number of key satellite sensors. One of the limitations in current analysis for the UK stems from the unpredictability and lack of observations as a result of cloud when any particular satellite views the UK. By enabling multiple satellites, which view the UK on different days, to have more consistent calibrations we can stitch together observations as if they were from the same satellite and more readily find the necessary frequency of observations to monitor the crops and consequently have more robust estimations of expected yield. In a future more dynamic system we will be able to enhance automated farming solutions where farmers can tune their fertiliser and water to maximise growth.
- University of Leicester will look at our atmosphere, evaluating the use of simulated TRUTHS observations to detect and count ‘droplets’ in clouds. The density and number of droplets varies as a function of cloud height and air quality, particularly human pollution. This study looks to show how TRUTHS will be able to differentiate clean and dirty clouds from space and how that impacts the reflection of sunlight back into space. The impact of clouds is known to be the biggest source of uncertainty on feedbacks within current climate models – how much are clouds cooling the Earth from reflection? Or warming it by absorbing infrared radiation emitted by the ground? This study may also show that TRUTHS will be able to detect potential sources of pollution. One of the goals of the project is to provide a 3D simulation to help the public visualise how a cloud is formed and how pollution changes their appearance.
An additional study, undertaken by a consortium of two UK SMEs, Assimila and Quarry One Eleven, is investigating how TRUTHS can serve commercial EO businesses- Identifying the services that they are likely to need in the next decade; assessing the benefits as they grow their businesses; and demonstrating how it can help them to become fully integrated into the global EO system of systems.
TRUTHS, was conceived at NPL and is the first of a new class of SI-Traceable satellites, (SITSats). SITSats are expressly designed to make measurements of the Earth system with unprecedented accuracy fully traceable to international standards the SI and at a level that allows it to become a reference against which other satellites can be calibrated. TRUTHS is implemented as an ESA EarthWatch mission funded by a consortium of European nations led by the UK. In this 150th anniversary of the SI it is timely that the mission, following an anticipated successful review, will complete its Phase B2, demonstrating that the design will be able to deliver the stringent science objectives and move forward towards implementation as the world’s first ‘metrology laboratory’ in space.
Mimicking in space the primary calibration facilities of NPL in Teddington, TRUTHS will serve as a calibration reference for many of the world’s Earth Observing satellites. One of the mission’s primary objectives, is to assess and harmonise often small but potentially significant differences/biases between sensors such as the Sentinels of the European Copernicus programme and those of other nations such as the US when looking for small signals of climate. However, for more commercial small satellite constellations -where absolute calibration has so far been less business-critical and would require unbearable investments-; TRUTHS will provide the means to perform a rigorous in-flight calibration, improving consistency within individual constellations and harmonisation with mainstream satellites of agencies such as the European Space Agency. In this way, TRUTHS is an enabler offering the prospect of significantly improved data quality and performance – helping moving from qualitative to trustworthy quantitative services, opening up new market opportunities.
Read more about TRUTHS here
20 Jun 2025
