EarthCARE lifts the clouds on climate models
EarthCARE Lays the Groundwork for More Accurate Climate Models
The European Space Agency's (ESA) EarthCARE satellite has been orbiting the Earth since May 2024, collecting crucial data on clouds and aerosols that can significantly impact the planet's energy balance. This balance is all-important in regulating our climate, and the satellite's findings are poised to sharpen the accuracy of climate models, which guide global climate policy and action.
The Complex Role of Clouds and Aerosols
Clouds and aerosols are known to have an overall cooling effect on the planet, but their interactions with incoming energy from the Sun and with thermal radiation that Earth emits back out to space are highly complex and not fully understood. As greenhouse gas emissions continue to warm the planet, it remains unclear how clouds will respond. A reduction in cloud cover, for instance, would allow more sunlight to reach the surface, amplifying warming.
Aerosols add another layer of uncertainty. They tend to cool the climate by reflecting sunlight and also by making clouds more reflective and longer-lived. However, recent shifts – from sharp declines in industrial pollution to huge plumes of wildfire smoke – could significantly alter their overriding role in the climate system. The full impact of these changes remains unclear.
The Importance of Climate Models
Predictions of future climate change rely on computer models that simulate the atmosphere, oceans, and the wider Earth system under different scenarios. Climate model representations of clouds, aerosols, and their interactions with sunlight and infrared radiation are based on simplified mathematical descriptions of their behavior, often relying on measurements and numerous assumptions.
EarthCARE's Unique Capabilities
Launched in May 2024, EarthCARE – an ESA Earth Explorer mission developed in partnership with the Japan Aerospace Exploration Agency (JAXA) – carries four specialized instruments designed to take different measurements of clouds and aerosols simultaneously. This synergy is key: by combining these observations, EarthCARE can work out important cloud properties such as how much water they contain and the size of the cloud particles.
Radiative Closure: A Breakthrough in Climate Research
One of the mission's key science goals is to achieve "radiative closure," which means directly linking measurements of clouds and aerosols with observed energy fluxes. This allows researchers to understand how incoming sunlight is scattered by cloud particles and Earth's surface, and consequently how much is reflected back to space.
The animation below presents a sequence of measurements acquired by EarthCARE over Typhoon Ragasa near the Philippines on 20 September 2025, and illustrates radiative closure. The animation first shows how data from EarthCARE's cloud profiling radar (CPR), atmospheric lidar (ATLID), and multispectral imager (MSI) are combined to derive vertical slices of properties such as cloud and precipitation water content.
Next, information from MSI's horizontal imagery is used to extrapolate these vertical cloud profiles across the satellite's track. By identifying pixels with similar optical properties, the system reconstructs the 3D cloud structure.
Using a computational technique known as radiative transfer modeling, this 3D cloud representation is then used to estimate how incoming sunlight is scattered by cloud particles and Earth's surface, and consequently how much is reflected back to space.
In the animation, this calculated reflected sunlight appears as the blue-shaded shaded horizontal strip and the red line at the top. This is then compared against independent measurements by EarthCARE's broadband radiometer (BBR), shown by the yellow line at the top, and the agreement is very good.
Implications for Climate Modeling and Forecasting
The data collected by EarthCARE are not only advancing our understanding of our climate but also delivering immediate benefits for day-to-day forecasting and climate services. At the European Centre for Medium-Range Weather Forecasts (ECMWF), researchers are working to assimilate EarthCARE data into their model in real-time.
By providing a more accurate picture of cloud locations at the start of a forecast, these data will help the model better capture the evolution of weather systems and deliver more reliable predictions. Work to integrate EarthCARE's data streams is progressing rapidly, and the system is on track to become operational very soon.
The Future of Climate Research
The release of EarthCARE's Level-2 data products marks a significant milestone in the mission's progress. The data are now available from the EarthCARE Online Dissemination Service, and researchers worldwide can begin testing new hypotheses, validating climate and weather models, and exploring how recent atmospheric changes – from wildfire smoke to shifts in pollution – are affecting the planet's energy balance.
The EarthCARE community is accelerating scientific progress and expanding the mission's reach by sharing tools and expertise across agencies and continents. As we continue to explore the complexities of our climate, the data collected by EarthCARE will play a crucial role in shaping our understanding of the planet and informing our actions to mitigate its impacts.
In conclusion, the EarthCARE satellite is a groundbreaking mission that is poised to revolutionize our understanding of clouds and aerosols and their impact on the planet's energy balance. The data collected by the satellite will have far-reaching implications for climate modeling, forecasting, and research, and will play a critical role in shaping our actions to mitigate the impacts of climate change.
