A new European mission, the Far-infrared Outgoing Radiation Understanding and Monitoring mission, or FORUM, will add a crucial measurement to help our understanding of Earth’s changing climate.

Measurements from the new spacecraft will improve confidence in the accuracy of climate change assessments that form the basis for future policy decisions.

FORUM will record far-infrared radiation emitted from Earth to space – extending beyond the parts of the infrared spectrum currently being measured. The measurements will help the study of Earth’s radiation budget – the balance between the incoming radiation mostly from the Sun at short wavelengths, and outgoing radiation, which is a combination of reflected radiation from the Sun and radiation emitted by the Earth system, much of it a longer wavelengths. When the budget is not balanced, the temperature of the planet can change, with consequences for the climate. Human activities have altered the atmosphere, changing the behaviour of the heat-conserving elements.

More than half of the outgoing longwave energy is in the far-infrared part of the electromagnetic spectrum, which will be measured for the first time by FORUM. This will give a clearer, more detailed picture of what is happening in different altitudes of the atmosphere, and allow more accurate tracking of atmospheric components, especially water vapour and ice clouds.

Josef Aschbacher, ESA’s Director of Earth Observation Programmes, said, “FORUM will measure, for the first time, the far-infrared part of the electromagnetic spectrum from space, thus allowing us to better understand the energy balance of our planet. FORUM will bring great benefits to climate science.
“Better understanding the complexity of our climate system and filling gaps in our knowledge is of critical importance as the consequences of climate change are far-reaching, affecting all facets of society and the natural world.”
The design of the mission will now be fine-tuned, and then built with a view to being launched in 2026.

FORUM is ESA’s ninth Earth Explorer mission. The series of satellites uses innovative measurement techniques to yield new insight into different aspects of the Earth system and the interactions that bind the system as a whole. They are designed and built to fill knowledge gaps identified by the scientific community, keeping scientists at the heart of the selection and development process.

FORUM and its competitor, the Sea-surface Kinematics Multiscale monitoring (SKIM) concept, were presented and discussed in detail with the scientific community at a User Consultation Meeting in Cambridge, UK, in July. While both missions would deliver outstanding value to science, ESA’s Advisory Committee for Earth Observation recommended FORUM for its planned impact on climate models, identifying climate prediction as a major global concern.

Further Information about ESA’s Earth Explorers:
FORUM team website: https://www.forum-ee9.eu/
FORUM report: https://esamultimedia.esa.int/docs/EarthObservation/EE9-FORUM-RfMS-ESA-v1.0-FINAL.pdf