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Artwork: UK-based companies have advised on the best way to build the satellite
Europe will launch a satellite to obtain a high-resolution image of the Earth's greenhouse effect.
The Forum's mission will include a spectrometer to detect far-infrared radiation from the Earth.
It is in this part of the long-wave electromagnetic spectrum that water vapor and carbon dioxide absorb energy very efficiently, which warms the planet.
Remarkably, this is not a region that has been exhaustively mapped before.
This means that scientists lack a number of key features in their climate models, including the detailed operation of some of the feedback reactions in the global atmosphere that amplify or mitigate global warming.
These omissions would include the behavior of certain types of cloud.
"Until now, satellite missions have primarily measured wavelengths in the mid-infrared, that is, less than 15 microns," says Dr. Helen Brindley of Imperial College London and the National Earth Observation Center of the United Kingdom.
"We are now looking to measure more than 15 microns, which has never been done before, with very high precision and very high spectral resolution, which means we can really see the fingerprints of different gases in the air. The atmosphere, especially the water vapor, and really get an idea of how the energy changes over time, "she told BBC News.
Forum is an acronym that stands for "understanding and monitoring of outgoing radiation in the far infrared".
The satellite concept was selected Tuesday for development by the delegates of the Earth Observation Program Committee of the European Space Agency (ESA) at a meeting in Frascati, Italy.
It belongs to the Earth Explorer class of the organization. These are experimental missions that make innovative science in areas of urgent environmental interest. Forum would be the ninth in the series.
It should go into orbit around a Vega rocket around 2025 or 2026. The budget should not exceed 260 million euros (230 million pounds sterling).
The project has strong British scientific support, led by Imperial Oil, but also considerable industrial commitment.
The British branches of Airbus and Thales Alenia Space are currently leading the two consortiums to determine the best way to build the half-ton spacecraft.
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The temperature of the Earth's surface would be several degrees below zero without the atmosphere.
The incoming short wave solar radiation is absorbed at the surface and reemitted at longer wavelengths, in the infrared.
In the absence of water vapor, carbon dioxide and other greenhouse gases in the air, this energy would immediately be returned to space.
But the molecules of these gases trap the radiation, warming the planet. And most of this absorption, more than 50%, occurs in the far infrared.
Meteorological satellites regularly observe the wavelengths of the average infrared to get an idea of the place of water in the atmosphere on the new weather fronts. But given the importance of water vapor for the greenhouse effect, one may wonder why far-infrared is not systematically mapped.
This is technology, says Dr. Hilke Oetjen of Esa. The necessary innovations have only recently become available and, even if such observations are now possible, Forum will still have to identify the atmosphere that is circumnavigating the world at 7 km / s.
"The problem is not the spectrometer instrument, but the detectors.They are relatively new," explained the project scientist Forum of the agency.
"We also need to use this" fixed step "technique – we need it because we are integrating (the information) for seven to eight seconds for a measurement, which is a huge time given the speed with which a satellite is flying. "
Step and Stare will see the satellite sample capture about 15 km distance in the atmosphere approximately every 100 km. Nevertheless, this should give a very good picture of the energy budget of far infrared around the world each month. If the mission functions during its initial four-year period, Forum will capture all the seasonal and interannual behaviors that scientists need to begin improving their models.
The work should ultimately dispel some of the uncertainty that currently surrounds projections for future climate change.
This will come from a better representation of features such as ice clouds in the models.
"We have actually adapted our models to what cirrus clouds look like to the measurements we have in the middle and visible infrared," said Dr. Brindley.
"What I guess we will discover is that the models are not necessarily suitable for far-infrared and that we will have to adjust them to better understand elements such as the size and shape of crystal particles This will probably have consequences for if these clouds heat or cool the planet. "
Beth Greenaway, responsible for Earth Observation and Climate at the British Space Agency, welcomed the selection of Forum.
She said: "Thanks to the investments of the British Space Agency, Britain could play an important role in this mission and ESA's" go ahead "is based on the fantastic science of the Imperial College London and the Transnational Missions Advisory Group, supported by detailed technical mission feasibility from studies conducted by British industrial teams.
"The selection of Forum – compared to other highly credible missions – is a real indication of the power of the UK's Earth Observation capability, which spans several universities and businesses."
[email protected] and follow me on Twitter: @BBCAmos
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