EarthCARE's Radiometer Reveals Insights into Earth's Energy Balance

EarthCARE's Radiometer Reveals Insights into Earth's Energy Balance
by Erica Marchand
Paris, France (SPX) Jul 08, 2024

ESA's EarthCARE satellite, still in its early stages of operation, has delivered its first images from the broadband radiometer instrument. These initial images provide a detailed look at Earth's energy balance, crucial for understanding our climate.

Earth's energy balance involves the amount of energy it receives from the Sun and the thermal radiation it emits back into space. This balance, influenced by factors like clouds, aerosols, and greenhouse gases, is essential for maintaining Earth's stable temperatures.

Human activities are increasing greenhouse gas concentrations, while aerosols enter the atmosphere from industrial, traffic, and agricultural sources, as well as natural events.

As global temperatures rise, monitoring the radiation balance is vital for studying and addressing climate-related issues. ESA and the Japan Aerospace Exploration Agency (JAXA) developed the EarthCARE satellite to measure various atmospheric aspects, enhancing our understanding of how clouds and aerosols affect solar energy reflection and infrared energy trapping.

Although launched just over a month ago, EarthCARE has already returned data from its cloud profiling radar. Now, its broadband radiometer is also proving its capabilities.

Simonetta Cheli, ESA's Director of Earth Observation Programmes, stated, "Of course we have never doubted the EarthCARE broadband radiometer's potential, but here we see, at such an early stage in the mission, that the instrument is working very well and delivering excellent data."

She added, "Each of the satellite's different instruments has an extremely important role to play - and when all of them are working in harmony and the satellite is commissioned, then the scientific community and weather forecasters will have a powerful tool to advance our understanding of Earth's energy balance, advance climate science and improve weather predictions."

The broadband radiometer measures radiative fluxes at the top of Earth's atmosphere. Its unique ability to view the atmosphere from three directions simultaneously-directly down, forward, and backward-enables accurate measurements of solar energy reflection and thermal energy emission.

On June 18, shortly after the broadband radiometer began its measurements, it captured brightness along EarthCARE's path over the western Mediterranean. The image spans about 1300 km from northern Spain to Algeria, showing bright white clouds (high solar energy reflection) in red and the darker sea (low reflection) in blue.

The transition from Spain's coast to the Mediterranean Sea shows minimal difference, while the switch from darker to brighter colors over Algeria is due to aerosols and thin clouds. Zooming into the Atlas Mountains, the radiometer's views reveal thunder clouds towering 10 km high, with their shadows appearing in different positions in each view.

This multi-angle observation is vital for a comprehensive understanding of reflected and emitted energy. Combined with data from EarthCARE's other instruments-the cloud profiling radar, atmospheric lidar, and multispectral imager-these insights are key to advancing climate science.