EarthCARE – the White Dragon – is in Space

The EarthCARE satellite is also known under its nickname ‘White Dragon’, embodying the satellite’s appearance, with its white body and solar panel resembling a long tail. On their web page, ESA writes that “In Japanese mythology, dragons are ancient and divine creatures that govern water and fly in the sky: an appropriate metaphor for a mission that will study clouds and aerosols.”

EarthCARE

EarthCARE is ESA’s 6^th Cloud, Aerosol, Radiation Explorer. It is also the largest and most complex of the European Space Agency’s (ESA’s) Earth Explorer missions. The mission is developed as a cooperation between ESA and the Japan Aerospace Exploration Agency (JAXA). Using four instruments it will examine the role that clouds and aerosols play in reflecting solar radiation back into space and in trapping infrared radiation emitted from Earth’s surface. Thus, the missions will advance our understanding of climate change.

EarthCARE is one of several research satellites in ESA’s Earth Explorers programme, each dedicated to observing a different aspect of Earth’s system, such as the Cryosphere, Hydrosphere, Atmosphere, and Ionosphere as well as the Earth’s interior. Current missions from the programme include CryoSat (ice mission), SMOS (Soil Moisture and Ocean Salinity), Swarm (magnetic field mission) and EarthCARE. Next in line up for launch are Biomass (forest carbon) and FLEX (photosynthesis).

Norwegian scientists’ use of EarthCARE

Many Norwegian researchers will use data from the Earth Explorer satellites. NILU, the University of Oslo (UiO), and Andøya Space AS are engaged in EarthCARE CalVal (Calibration/Validation).

NILU supports the EarthCARE mission with two activities; the Norwegian initiative for EarthCARE Validation of Aerosol uncertainties and Radiation products in the Arctic project (NEVAR), and the EVDC.

NILU’s NEVAR project

“The NEVAR project aims at supporting the geophysical validation of the EarthCARE data products,” explains Dr Kerstin Stebel. She is project manager for NEVAR, and a senior scientist at NILU’s Atmosphere and Climate Department (ATMOS). NEVAR started with preparatory activities in November 2022, such as mapping of the CalVal capabilities in Arctic countries, and contribution to best practice validation protocols.

NEVAR will focus on two areas:

1. The Evaluation of EarthCARE total column aerosol observations and their uncertainties, with specific focus on the regional assessments on aerosols in the Arctic.
2. The Evaluation of Radiation Products. The simulated radiation data will be evaluated against the EarthCARE observations.

“Recently, we have been developing software tools using simulated EarthCARE data, so that we are ready for the actual validation of the EarthCARE products once the data from the will be released,” Stebel says.

According to Stebel’s colleague, senior scientist Arve Kylling, it is very interesting to access how horizontal cloud variability affects the uncertainty and variability in radiation. He will analyse this by comparing 1D and 3D Radiative Transfer Modelling results for selected locations in the Arctic where relevant surface data are available to give further constraints and for locations with large seasonal changes in surface albedo (snow/not snow).

Vital data storage at NILU – EVDC

“We are very excited about the launch of EarthCARE,” says Ann Mari Fjæraa, another ATMOS senior scientist. “We have been operating the EVDC data centre on behalf of ESA for many years. Currently we are involved in data activities from more than 200 scientists working across around 40 international teams.”

These teams are performing crucial satellite Cal/Val from ground-based measurements all over the globe.  The EVDC data centre plays a unique and vital role in storing data for this global collaboration, ensuring the accuracy and reliability of the EarthCARE satellite’s observations. This is again essential for advancing our understanding of the Earth’s atmosphere and climate.

ESA’s Cloud, Aerosol, Radiation Explorer

EarthCARE is equipped with four state-of-the-art instruments. They work together to provide a holistic view of the interplay between clouds, aerosols, and radiation.

• The satellite’s atmospheric lidar (ATLID) delivers cloud-top information and profiles of thin clouds and aerosols.
• The cloud profiling radar (CPR), provided by JAXA, provides information on the vertical structure, motion, and internal dynamics of clouds.
• The multispectral imager (MSI) offers a wide-scene overview in multiple wavelengths.
• The broadband radiometer (BBR) directly measures reflected solar radiation and outgoing infrared radiation.

By using all four instruments at the same time, our understanding on the impact of clouds and aerosols on reflecting sunlight and trapping heat can be directly correlated with measured reflected solar radiation and emitted thermal radiation combined on one satellite. EarthCARE will measure vertical profiles of cloud particles and aerosols, and their fall speed towards ground. This provides new insights into interactions between clouds, aerosols, and precipitation. It will also register the distribution of water droplets and ice crystals and how they are transported inside the clouds.

This essential data will improve the accuracy of both cloud development models and their behaviour, composition, and interaction with aerosols. In addition, it will improve future climate models and support numerical weather prediction.