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A benchmark for climate data
ESA goes to great lengths to ensure that data beaming back to Earth from satellites is as reliable as possible. But how can we be sure that measurements from space are truly accurate, especially when it comes to the all-important data needed to assess climate change?
The Traceable Radiometry Underpinning Terrestrial- and Helio-Studies mission, or TRUTHS for short, will lay any such doubts to rest. This new satellite, which ESA is building under the umbrella of its Earth Watch programme and on behalf of the UK, will provide traceable International System of Units (SI) measurements of incoming solar radiation and of radiation reflected from Earth back out into space, with which to calibrate data from other satellites. In effect, TRUTHS will be a ‘standards laboratory in space’, setting the ‘gold standard’ for climate measurements.
There is little doubt that human activity is having a disastrous effect on Earth’s natural processes – and it seems we are on the brink of catastrophe unless the climate crises is addressed. When it comes to underpinning decision-making, satellite data records are critical – but confidence in these data is of utmost importance. TRUTHS will provide the benchmark reference for radiation measurements to improve our understanding of climate change and help increase the precision of climate models. This will help to monitor the effectiveness of international policy to fight the climate crisis.
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Essentially, the amount of incoming solar energy compared to the amount that bounces back to space controls our climate. An accurate knowledge of these energy exchanges is fundamental to understanding and monitoring change. The TRUTHS satellite carries two main instruments: the Cryogenic Solar Absolute Radiometer and the Hyperspectral Imaging Spectrometer as well as a novel onboard calibration system.
Together, these instruments will make continuous measurements of both incoming solar radiation and reflected radiation. These two observations will be used to evaluate the energy-in to energy-out ratio. The spatial and spectral resolution of the mission will allow greater understanding of the causes of change in energy balance and help assess progress stemming from climate action. The unprecedented quality of these measurements will also offer the standard reference against which observations from other satellites can be corrected.
NASA is also developing the CLARREO Pathfinder instrument, which will fly on the International Space Station, and an overarching CLARREO satellite concept – both similar to TRUTHS. Together, these are set to be founding elements of an international climate and calibration observatory.
TRUTHS is being developed by ESA and is led by the UK Space Agency with participation from Switzerland, Greece, Romania and Czech Republic, with Airbus UK as the prime contractor.
