The Earth Cloud Aerosol and Radiation Explorer (EarthCARE) satellite mission will advance our understanding of the role that clouds and aerosols play in reflecting incident solar radiation back out to space and trapping infrared radiation emitted from Earth’s surface.
Energy in the atmosphere is balance between incoming light from the Sun, which heats Earth, and outgoing thermal radiation, which cools Earth.
Clouds and, to a lesser extent, aerosols reflect incident solar light back out to space, but they also trap outgoing infrared light. This leads to a net effect of either cooling or heating of the planet.
In addition, aerosols influence the life cycle of clouds, and so contribute indirectly to their radiative effect.
The effect of clouds on atmospheric heating and cooling is not only much stronger than the effect of greenhouse gases such as carbon dioxide, but also much more complex owing to the complicated structure of clouds. Furthermore, the life cycle of clouds depends on the temperature, moisture and dynamics of the atmosphere.
Clouds remain one of the biggest mysteries in our understanding of how the atmosphere drives the climate system. An improved understanding and better modelling of the relationship between clouds, aerosols and radiation is therefore one of the highest priorities in climate research and weather prediction.
EarthCARE will provide global profiles of clouds and aerosols along with measurements of solar radiation reflected from the planet and thermal radiation emitted from the planet. To do this, the satellite carries two large instruments: a lidar to measure vertical profiles of aerosols and thin clouds, and a radar to measure vertical profiles of thick clouds and precipitation.
Two other instruments, a cloud imager and a broadband radiometer that measures the reflected solar radiation as well as the emitted thermal radiation of the clouds, complete the satellite’s suite of sensors. The use of these instruments means that 3D cloud and aerosol scenes can be directly related to reflected solar and emitted thermal radiation.
EarthCARE will acquire global datasets of cloud and aerosol profiles at the same time. This will help to evaluate and improve how clouds are represented in atmospheric models. Furthermore, EarthCARE data will be used in numerical weather prediction models to study how cloud profiles can improve weather forecasts.
The EarthCARE lidar and radar instruments are the most advanced cloud and aerosol profiling instrument even flown in space. The lidar will be able to distinguish clouds and different types of aerosols. The radar will be able to detect vertical motion within clouds, which will lead to a much better understanding of convection and ice & rain fall speed, leading to improved drizzle, rainfall and snowfall rates.
EarthCARE is the largest and most complex Earth Explorer mission to date.