In a remarkable feat of engineering and international collaboration, the EarthCARE satellite launched successfully earlier this year, on May 28, 2024, from Vandenberg Air Force Base in California.
This joint European-Japanese mission aims to revolutionize our understanding of how clouds and aerosols influence Earth’s climate. Developed by the European Space Agency (ESA) in cooperation with the Japan Aerospace Exploration Agency (JAXA), EarthCARE carries four sophisticated instruments that will work in synergy to provide unprecedented insights into the complex interactions between clouds, aerosols, and radiation.
The data collected will help improve weather forecasts and climate predictions.
A Mission 20 Years in the Making
Professor Anthony Illingworth and his colleagues from the University of Reading proposed the EarthCARE concept in 1993. After years of planning and development, ESA and Astrium GmbH (now part of Airbus) signed a €263 million contract in 2008 for the satellite’s design, development, and integration. Construction began in earnest in 2009, and the project was ultimately valued at €850 million.
The UK played a significant role, with companies like SSTL, Thales Alenia Space UK, and Teledyne e2V supplying key instruments and components. Airbus built the satellite’s main structure in Stevenage. Technical challenges, particularly with the atmospheric lidar instrument, led to launch delays. But the EarthCARE team persevered, delivering a satellite that pushes the boundaries of Earth observation technology.
Innovative Instruments for Unprecedented Insights
At the heart of EarthCARE’s groundbreaking capabilities are its four state-of-the-art instruments: The Atmospheric Lidar (ATLID) uses a powerful UV laser to profile thin clouds and aerosols. The Cloud Profiling Radar (CPR) penetrates thick clouds to reveal their internal structure and dynamics. The Multispectral Imager (MSI) provides contextual information across seven spectral bands. The Broadband Radiometer (BBR) measures reflected solar radiation and emitted thermal radiation. A consortium of European and Japanese companies and research institutions provided these instruments. Notably, the MSI comes from SSTL in the UK, while Thales Alenia Space UK developed the BBR with its telescope from RAL Space.
The CPR is the first space-borne W-band radar with Doppler capability. Operating at 94 GHz, it achieves a sensitivity of -35 dBZ at 20 km altitude with a horizontal resolution of 500 m and vertical resolution of 100 m.
This allows it to detect thick clouds, light rain, and snow. ATLID is a high spectral resolution lidar that separates molecular backscatter from particle backscatter at its UV wavelength of 355 nm. Measuring depolarization can differentiate between spherical and non-spherical particles like ice crystals. With a vertical resolution of 103 m, it provides detailed profiles of aerosols and thin clouds. The MSI’s seven channels span visible, near-infrared, shortwave infrared, and thermal infrared wavelengths.
Its 150 km swath provides context for the active instruments. At the same time, the BBR’s three fixed views (forward, nadir, backward) allow retrieval of top-of-atmosphere fluxes and help constrain radiative transfer calculations.
Synergy for Climate Science
What makes EarthCARE genuinely groundbreaking is how its instruments work together. By combining their measurements, scientists can untangle the complex web of interactions between clouds, aerosols, and radiation with unprecedented detail.
Initial results unveiled in October 2024 demonstrate this synergy in action. In one example, the instruments work together to probe a severe thunderstorm: The radar detects the storm’s precipitation and vertical motions.
The lidar profiles the icy upper layers of the anvil cloud. The image captures the horizontal extent of the storm system. The radiometer measures the cooling effect at the cloud top and warming within the cloud. In another case, EarthCARE examines a high-altitude cirrus cloud: The lidar provides a detailed profile through the thin cloud. The radar focuses on heavier ice crystals in the lower layers. The radiometer reveals the net warming effect from trapped thermal radiation.
Ultimately, EarthCARE aims to quantify the impact of different cloud and aerosol scenarios on Earth’s radiation budget. The mission will clarify some of the most significant uncertainties in climate science by measuring the entire lifecycle of clouds and aerosols—from their formation and interactions to their radiative effects.
EarthCARE demonstrates the power of international collaboration in Earth science. ESA and JAXA joined forces to share expertise, technology, and resources for this ambitious mission. Additionally, the project engaged aerospace companies, research institutions, and universities from across Europe, Japan, and beyond.
The UK made substantial contributions through Airbus, SSTL, Thales Alenia Space, Teledyne e2V, and several universities. Scientists like Dr Robin Hogan from ECMWF and Dr Shannon Mason from the University of Reading played critical roles in algorithm development and mission planning. This collaborative approach made the mission possible and fostered knowledge sharing and technological advancement to benefit the global Earth science community for years. By working together across borders and disciplines, the EarthCARE team is helping to build a more sustainable future for our planet.
The insights gained from EarthCARE have far-reaching implications for weather forecasting and climate modelling. By better understanding cloud-aerosol-radiation interactions, scientists can improve the accuracy and reliability of their predictions. On a day-to-day basis, EarthCARE’s data will help meteorologists better forecast cloud and precipitation patterns. This could lead to more timely severe weather warnings and optimized water resource management. Industries from agriculture to renewable energy stand to benefit. In the longer term, EarthCARE will enhance climate models by filling gaps in our knowledge of clouds as climate feedback mechanisms.
Most models suggest that cloud cover will decrease in a warming world, amplifying temperature rise, but huge uncertainties remain. EarthCARE’s global observations will test these predictions and help refine regional climate projections. Ultimately, the mission’s legacy will be a clearer picture of our changing planet and a stronger foundation for science-based decision-making. EarthCARE is paving the way to a more sustainable and climate-resilient future by shedding light on the mysteries of clouds.
– The EarthCARE satellite, a joint European-Japanese mission, launched in May 2024 to study how clouds and aerosols influence Earth’s climate
– Its four innovative instruments—a UV lidar, cloud radar, multispectral imager, and broadband radiometer—work in synergy to provide unprecedented insights
– Initial results showcase EarthCARE’s ability to profile cloud structure, aerosol layers, precipitation, and radiative effects
– The data will help improve weather forecasts and climate predictions, with implications for industries, policymakers, and our understanding of climate change
– EarthCARE exemplifies the power of international collaboration in advancing Earth science for a more sustainable future
