ESA Top Multimedia

This video features five frames from the NASA/ESA Hubble Space Telescope spanning from 2014 to 2023 of R Aquarii, a symbiotic binary star that lies only roughly 1000 light-years from Earth in the constellation Aquarius. This is a type of binary star system consisting of a white dwarf and a red giant that is surrounded by a large, dynamic nebula.

These frames show the brightness of the central binary changing over time due to strong pulsations in the red giant star. The central structures can also be seen to be spiralling outwards due to their interaction with material previously ejected by the binary. 

This time-lapse highlights the value of Hubble’s high resolution optical observations in the changing Universe, known as time-domain astronomy.

With the initial images from each of the instruments aboard ESA’s EarthCARE satellite now in hand, it's time to reveal how these four advanced sensors work in synergy to measure how clouds and aerosols influence the heating and cooling of our atmosphere.

The animation, which features data from 18 September 2024, shows the multispectral imager mapping different types of cloud and first features a thunderstorm over Milan, Italy, and then low marine clouds over the Baltic Sea and high-altitude cirrus cloud over Sweden. The broadband radiometer registers the reflected solar radiation as measured at the top of the atmosphere, where red corresponds to high values and blue to low values. The measured thermal radiation emitted from Earth is not shown in the animation. The cloud profiling radar takes a full vertical profile of the bulk of the thundercloud as it is more sensitive to water droplets and precipitation, while the cirrus cloud made of ice particles does not give a strong signal. However, these are detected by the atmospheric lidar, which clearly captures ice particles suspended at the top of both clouds. Both instruments are needed to retrieve the full top to bottom cloud profile as the synergy slide shows, overlapping all areas. With this at hand, EarthCARE’s synergistic data products are enabled, such as the total water content in the atmosphere.

The overall heating effect of cirrus clouds, particularly in their upper layers, is evident where the clouds absorb both solar radiation as well as thermal radiation from the Earth’s surface. This warming effect is interrupted where the cloud thickens and larger ice particles form, blocking the thermal radiation being emitted from Earth’s surface. In these denser regions, the cloud top cools by emitting thermal radiation into space. Despite these localised cooling effects, cirrus clouds contribute to the overall warming of the atmosphere.

Read full story: EarthCARE synergy reveals the power of clouds and aerosols