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NCEO leads ESA VERIFY campaign to validate data from EarthCARE

NCEO Dr Kamil Mroz is leading a special campaign with support from the FAAM Airborne Laboratory, National Centre for Atmospheric Science (NCAS), and the European Space Agency (ESA) to under-fly ESA’s latest research satellite EarthCARE.  The team are validating EarthCARE’s cloud droplet and velocity measurements by using cloud probes fitted to the FAAM Airborne Laboratory’s atmospheric research aircraft – as part of a project called VERIFY.

The success of the project is depends on a complex operation; co-ordinating information on satellite orbits, potential flight plans and expected cloud formations to optimise the flight paths. The research flight must fly directly under the path of the satellite as it orbits hundreds of kilometres above the Earth’s surface, in optimum weather conditions.

The research aircraft flies through the clouds, observing them from the inside, while the satellite looks at them from above – using advanced lidar and radar technology that has never been used in space before. By combining these perspectives, scientists can calibrate the satellite’s instruments and fine-tune the complex algorithms to better align with the actual cloud properties being measured.

Speaking to Dr Kamil Mroz, the lead scientists on the flights and a radiation and rainfall scientist at the National Centre for Earth Observation, about the EarthCARE satellite and the VERIFY project:

What is the EarthCARE satellite and how is it studying weather and climate from space?

Launched in May 2024, the EarthCARE satellite is looking at how clouds, aerosols (tiny particles in the atmosphere like dust) and radiation interact to affect the Earth’s atmosphere. EarthCARE is the most sophisticated satellite in the Earth Explorers programme, using lidar and radar technology that has never been flown in space before.

EarthCARE orbits the Earth at an altitude of 393 km, so it relies on remote sensing measurements. It uses complex algorithms to turn its measurements into information about the number of cloud droplets or ice particles, their size and shape, and amount of precipitation. In order to know if these algorithms are working correctly, as well as the lidar and radar instruments on board the satellite, researchers need to calibrate data collected in space with data collected much closer to the clouds. 

EarthCARE is the latest Earth Explorer satellite, developed as a joint venture between the European Space Agency (ESA) and the Japanese Aerospace Exploration Agency (JAXA).  

How are scientists calibrating the satellite and sampling clouds?

“Scientists from the National Centre for Earth Observation, National Centre for Atmospheric Science (NCAS), and ESA are calibrating the satellite and validating its measurements by using cloud probes fitted to the FAAM Airborne Laboratory’s atmospheric research aircraft – as part of a project called VERIFY,” explains Dr Kamil Mroz, the lead scientist for VERIFY.

The research aircraft flights follow directly under the path of the satellite as it orbits hundreds of kilometres above the Earth’s surface. The aircraft flies inside the same part of the cloud that the satellite is observing from above, and takes measurements of the clouds’ physical properties. Over the past month, the VERIFY project has completed 4 flights – totalling around 16 hours of airtime. More flights are expected in early 2025.   

The aircraft’s cloud probes capture images of snowflakes and ice crystals inside clouds, which atmospheric scientists analyse to see how many and what type of particles make up the clouds the research aircraft has flown through. They can then compare these results to the information derived from the satellite observations.

“The VERIFY team set out to sample several types of clouds – from cumulus (puffy, low-altitude clouds) to cirrus (wispy, high-altitude clouds) and aerosols like Saharan dust. Weather systems are made up of different types of clouds, and even within the same system, several cloud types can be seen. Some clouds produce rain or snow that reaches the ground, while others don’t, but they are still important because they reflect sunlight or trap heat, affecting the Earth’s temperature. It’s important to know if EarthCARE can differentiate between these cloud types and provide accurate data under all weather conditions.”

What will weather forecasters and climate action decision-makers learn from EarthCARE?

Researchers use large and complex computer models to simulate Earth’s atmosphere to forecast weather and predict how our actions impact the future climate. Satellites like EarthCARE feed data into these models, so it is vital to be sure that the data they send is accurate. The FAAM Airborne Laboratory’s research aircraft can fly into the atmospheric conditions these models are trying to simulate, gathering real-world data to confirm that the satellite is working as it should.

EarthCARE represents a major advancement in our ability to understand Earth’s atmospheric processes.

He explains how with innovative technology and a rigorous approach to validation, this mission will provide the scientific community with high-quality data that can drive new insights into the interactions between clouds, aerosols, and the planet’s climate: “The partnership between space-based and in-situ measurements not only underscores the importance of collaborative science but also highlights the cutting-edge techniques needed to unravel the complexities of Earth’s climate system.”

Over its mission lifetime of three years, EarthCARE will advance our understanding of cloud properties and processes, paving the way for future discoveries in atmospheric science.