With the launch of EarthCARE, ESA’s most complex Earth Explorer satellite yet, clouds, aerosols and radiation are about to become a whole lot clearer – at least scientifically.

A unique blend of four instruments will work together to resolve some of the most mysterious aspects of our atmosphere. The data will be invaluable for improving climate models.

To celebrate the mission’s launch, here – in no particular order – are ten reasons to be excited about EarthCARE. 

1. Clouds are mysterious

Given that they’re so big, fluffy and ubiquitous you would be forgiven for thinking we might already know all there is to know about clouds. In fact, there is a lot we don’t know.

While considered to have a cooling effect, the impact of clouds on the current and future climate is not fully understood. EarthCARE will improve our understanding of clouds, how they reflect sunlight back to space and trap heat in the atmosphere. We’ll learn more about climate processes, and much more besides.

Its multispectral imager will differentiate between types of clouds, while the atmospheric lidar will tell us the altitude of the top of clouds. The cloud-profiling radar (CPR) provided by the Japan Aerospace Exploration Agency (JAXA) will penetrate all but the thickest of clouds – including hurricanes - to give us a detailed look at their structure and content, how they form and dissipate, and can spot light rain and drizzle, and how they move vertically.

We’ll also be able to look right into the eye of a tropical storm.

2. Aerosols are even more mysterious than clouds

Essentially, all cloud water droplets and ice crystals start with an aerosol particle. That could be a speck of wind-swept Saharan dust, tiny soot particles from industrial pollution, or even salts blown high into the sky from ocean spray.

In this way aerosols have a direct impact on radiation and climate, with different aerosol types either cooling or heating the atmosphere depending on their shape or orientation. Then there is their indirect impact through forming clouds.

Overall, aerosol emissions generated due to human activities have had a cooling effect, but this might change in the future. EarthCARE’s unique mix of instruments, including its aerosol-identifying lidar, will be key for understanding how.

3. It’s getting hot in here

We have already mentioned it, but the question of radiation balance is at the heart of EarthCARE’s mission.
The fourth in the suite of EarthCARE’s instruments is the broadband radiometer that will measure reflected solar radiation and outgoing infrared radiation.

In combination with EarthCARE’s other instruments, it will help us understand the contributions of clouds and aerosols to this radiation balance.

It comes at a critical time. Our climate is undeniably changing, driven by increasingly rapid rises in global temperatures. Some of the effects can be seen every day and have already been severe.

The huge missing piece of the puzzle that EarthCARE provides will improve models of our atmosphere now and in the future, giving us the best possible chance to prepare for and perhaps help mitigate what is to come.

4. Not just clouds and aerosols

Whilst clouds and aerosols might be at the forefront of EarthCARE’s investigations, that is not all the satellite can spot from space.

Every now and then, when the conditions are right, locusts swarm in unimaginably large and voracious numbers and devour pretty much anything green lying in their path.

These clouds of flying insects, too, can be spotted by EarthCARE.

There is actually a lot of biological stuff floating or flying around high up in the atmosphere – from insects to pollen and even microorganisms such as bacteria. Telling these apart from other aerosols is all part of the challenge!

5. EarthCARE will improve weather forecasts

Clouds are an integral feature of the weather. There would not be much rain without a hefty nimbus cloud or two around.

Whilst EarthCARE was in preparation, despite it being beyond the mission’s initial scope, forecasters at ECMWF were already investigating whether the satellite’s novel cloud data might contribute to weather prediction.

To do that, they had to check whether information such as radar and lidar data could be added to their global weather models.

Using data from past missions, such as NASA’s CloudSat and the NASA/CNES CALIPSO satellite, they already started seeing improvements in prediction of temperature, wind, and precipitation.

Then Aeolus came along, carrying a very similar lidar instrument to EarthCARE’s. Aeolus’s wind data hugely boosted weather forecasts, and scientists have already been using its data to prepare the way for EarthCARE.

With all the novel cloud data about to be revealed, it will be an exciting few years for weather forecasters. 

6. A flying laboratory

EarthCARE will fly instruments that have never flown before to observe the atmosphere from space. It is ESA’s most complex Earth Explorer satellite yet, and that’s saying something!

The Atmospheric Lidar can, for the very first time, differentiate between aerosol types – things like sea salt, dust, smoke, pollution - without a-priori assumptions on their composition.

The CPR is the first radar that can detect not only cloud particles, but also their vertical motion, i.e. cloud water droplets, ice crystals and light rain. It boasts a number of firsts, including being the world’s first W-band Doppler radar on board a satellite.

The fact that all these instruments -pioneers in their own right- will work together to answer a common question, is even more impressive.

7. A close international collaboration

EarthCARE has been developed in close international collaboration between ESA and the Japan Aerospace Exploration Agency, JAXA, with JAXA providing the Cloud Profiling Radar.

Collaboration on the science has led to the joint exploitation of the mission with a huge array of products being created from the data produced in ground processing systems in both Europe and Japan.

The collaboration with JAXA also means EarthCARE has a nickname: the White Dragon.

International collaboration has also been key for the scientific preparation of the EarthCARE mission with numerous partners in Europe, Japan, the US and beyond.

8. Free and open data

EarthCARE data are free and open, allowing scientists and services to use them to build climate record data by combining with those from other missions, or by integrating the data to develop and improve applications.

One application we have already mentioned is weather forecasting, already an extra string to EarthCARE’s bow, but there will undoubtedly be more. ESA’s Earth Explorers often find unique and unforeseen uses, such as SMOS and Swarm combining to monitor space weather in near-real time.

It will be exciting to see what the global scientific community comes up with.

9. Global validation campaigns boost science

An extensive network of scientists is waiting to validate EarthCARE data, by assessing them in comparison to reference data that will be collected from other satellite, airborne, shipborne, and ground-based sensors.

Several large, international validation campaigns include flights under EarthCARE’s orbit to achieve this goal.

An extra bonus from such campaigns is all the extra science that will be done. Whilst improving the data EarthCARE sends us from above, teams on the ground and in the air are almost sure to trial new instruments and collect novel data that improve our understanding of our atmosphere and pave the way for the next generation of Earth observation satellites.

10. EarthCARE adds value to other missions

EarthCARE, in addition to its novel data, will continue the invaluable climate records generated by satellites that have finished their missions, whilst extending them in anticipation of future spaceborne instruments.

As an example, whilst EarthCARE has been in development scientists from the Royal Netherlands Meteorological Institute (KNMI) have been applying its lidar algorithms to Aeolus and CALIPSO data to improve existing data products and prepare for future observations.

Data from EarthCARE are foreseen to extend the record of missions such as Aeolus, CALIPSO, CloudSat, GPM, CERES and GERB, and prepare the path for missions such as Aeolus-2, AOS and Libera that are due to launch in the coming decade.