The energy balance on Earth - determined by the Sun's incoming energy and the thermal radiation Earth emits - relies on a complex interplay of factors like clouds, aerosols, and greenhouse gases, which together regulate climate. Although clouds and aerosols generally cool the atmosphere, the mechanisms governing their interactions with solar and infrared radiation are intricate and not yet fully understood.

Launched in May 2024, the EarthCARE mission, a collaborative project by ESA and the Japan Aerospace Exploration Agency (JAXA), aims to quantify how clouds and aerosols reflect solar energy back into space and trap infrared energy, warming the atmosphere.

ESA's Director of Earth Observation Programmes, Simonetta Cheli, commented, "Although we are still in the early stages of the mission and busy with the satellite's commissioning phase, the results we present are truly remarkable. Not only do they further confirm that all four instruments and the complex way the data are processed are functioning exceptionally well, but they also highlight the power of their combined measurements. This demonstrates that the mission is on track to achieve its objectives. The data, which were captured on 18 September, offer a sweeping view from Central Europe to Sweden. Notably, they reveal the many different signatures of a thunderstorm over northern Italy, near Milan where we are today."

EarthCARE's instruments include a cloud-profiling radar, developed by JAXA, which provides vertical profiles of clouds, detailing internal cloud dynamics. The atmospheric lidar measures aerosol distribution and thin cloud profiles, the multispectral imager provides a broad-scene overview in various wavelengths, and the broadband radiometer measures both reflected solar and outgoing infrared radiation.

A featured animation demonstrates EarthCARE's ability to monitor both a recent thunderstorm and cirrus clouds. During the storm, EarthCARE's cloud radar captured data on large particles within the thunderclouds, while the lidar identified ice layers near the top of the clouds, revealing essential details on the upper structure.

The synergy between the cloud radar and lidar is showcased near the cloud tops, where combined data yield a more detailed view of the storm's structure. Findings indicate a cooling effect at the storm's upper regions, where thermal radiation is released into space, while lower cloud layers absorb heat from Earth's surface, creating a warming effect.

Cirrus clouds over Sweden were also analyzed. While these high-altitude, thin ice clouds allow sunlight to reach Earth's surface, warming it, they also trap infrared radiation emitted from the surface, producing a warming effect. The lidar provides detailed data over the cirrus cloud's height (8-13 km), while the radar focuses on lower levels where larger ice crystals form. In dense regions, the clouds emit thermal radiation outward, cooling the cloud tops despite their overall warming effect on the atmosphere.

Additional observations include a low-level aerosol layer over Germany, likely caused by pollution, and a low-altitude marine cloud over the Baltic Sea.

Thorsten Fehr, ESA's EarthCARE Mission Scientist, noted, "Having the data available at this early stage is a testament to the outstanding work of the EarthCARE team, particularly the scientists who developed these data products. This highlights EarthCARE's unique capability to simultaneously provide direct measurements of both clouds and aerosols, enabling an unprecedented assessment of their impact on climate."

Reflecting the ESA-JAXA collaboration, JAXA's Senior Chief Officer on Earth Observation Missions, Hitonori Maejima, stated, "By combining measurements from its four sensors, EarthCARE can capture different types of cloud, aerosols and their function. This is a symbol of the collaboration between ESA and JAXA."

Related Links
EarthCARE at ESA
Earth Observation News - Suppiliers, Technology and Application