FORUM

Mission Summary

The Far-infrared Outgoing Radiation Understanding and Monitoring (FORUM) mission is ESA’s 9^th Earth Explorer, designed to measure, for the first time, the Earth’s outgoing longwave radiation across the entire far-infrared with high spectral resolution and accuracy. The mission goal is to use these measurements to constrain the processes that control far-infrared radiative transfer and hence enhance our understanding of the Earth’s Greenhouse Effect and critical climate feedbacks due to water vapour and cloud. The observations will also be used to retrieve mid-upper tropospheric water vapour, ice cloud microphysics and, where possible, far-infrared surface emissivity.

Video caption: ESA’s Earth Explorer FORUM mission will provide new insight into the planet’s radiation budget and how it is controlled. Earth’s surface temperature is driven by the radiation balance at the top of the atmosphere, but this balance has been disturbed by the emission of greenhouse gases that are trapping heat in the atmosphere that would otherwise escape into space.

Instrument payload

The FORUM payload consists of two instruments flying on the same polar orbiting satellite. The FORUM sounding instrument (FSI) will measure the outgoing energy spectrum, covering the range 6.25-100 microns. Each observation will be integrated over a 15 km diameter footprint at the Earth’s surface. The FORUM embedded imager (FEI) will measure in just one wavelength channel but at much higher spatial resolution to identify features contained within the FSI footprint and assist the interpretation of the FSI observations.  Flying FORUM in loose formation with the MetOp-SG satellite carrying IASI-NG, a mid-infrared instrument covering the spectral range 3.6-15.5 microns, will facilitate the first ever measurements of the complete outgoing longwave energy spectrum of the Earth.

NCEO’s role in the mission

NCEO scientists at Imperial College and Leicester University are helping to shape the mission, including developing bespoke ground-based and airborne instrumentation and performing spectroscopic studies which will aid with the interpretation of the measurements when they become available.

Read the UK Space Agency blog to learn how FORUM will improve the accuracy of climate change forecasts.

‘If our simulations are right, on the global average the region is responsible for over half of the Earth’s emission to space. Put another way, atmospheric absorption within the far-infrared makes a major contribution to the Earth’s Greenhouse effect.’ Professor Helen Brindley, Imperial College London and NCEO Director

Mission facts

Provisional Launch Date: 2027
Orbit: Sun-synchronous polar
Mission Duration: 5 years
Mission Advisory Group members: Prof. Helen Brindley, NCEO, Imperial College London (Science Lead); Dr Jeremy Harrison, NCEO, University of Leicester
Funding Agency: ESA

Key Publication

Palchetti L, H. Brindley, R. Bantges, S. Buehler, C. Camy-Peyret, B. Carli, U. Cortesi, S. Del Bianco, G. Di Natale, B. Dinelli, D. Feldman, X. Huang, L. Labonnote, Q. Libois, T. Maestri, M. Mlynczak, J. Murray, H. Oetjen, M. Ridolfi, M. Riese, J. Russell, R. Saunders and C. Serio, 2020. FORUM: unique far-infrared satellite observations to better understand how Earth radiates energy to space, Bull.