New satellites detect plant glow and issue fire alerts

 

Gustav Sjöholm/TT

 

Published 07.14

       

       Oceans, fires, and photosynthesis. ESA’s two new satellites aim to increase knowledge and provide             faster alerts. Photos: Jessica Gow/TT, Achilleas Chiras/AP, Henley Spiers/AP

New satellites will provide faster alerts regarding forest fires, monitor the health of the oceans, and track the faint glow emitted by plants.

"We can detect things happening before they become visible," says researcher Marco Celesti.

When plants absorb sunlight and convert water and carbon dioxide into oxygen through photosynthesis, they also emit a faint glow known as fluorescence. The human eye cannot distinguish this glow from other light, but the sensitive sensor on the Flex satellite can.

"It feels like something straight out of sci-fi. Just imagine being able to see fluorescence—and managing to do so from a distance of over 800 kilometers," says Marco Celesti, an Earth observation scientist at the European Space Agency (ESA).

In early September, ESA is set to launch Flex into Earth's orbit, from where it will monitor this light.

"We get an immediate snapshot of actual photosynthesis."

Visible instantly

Other satellites can track how green vegetation is over time. Flex sees what is happening inside the plant as it occurs.

"So, when photosynthesis changes—for instance, due to a lack of water or nutrients—it reacts immediately. This allows us to detect stress factors before they become visible," says Celesti.

Researchers hope to gain new insights into how photosynthesis varies and its connection to the atmospheric carbon dioxide levels driving global warming. – Hopefully, we will understand how plants and vegetation will adapt in the future.

"A workhorse"

Flex is joined on the rocket by Sentinel-3C, which will take up orbit alongside its siblings, 3A and 3B. It focuses primarily on the oceans, gathering data on temperature, color, sea levels, and overall ocean health.

– If I had to describe it in one word, it would be "workhorse." It performs so many different tasks and is crucial to much of the information we collect regarding weather, climate, and pollution, says Simon Proud, an optical space scientist at ESA.

While Flex is specialized, Sentinel-3C is packed with instruments capable of providing information on the atmosphere and land as well. A new feature for this satellite is faster data transmission—enabling wildfire alerts within one hour—following a request from the Swedish Meteorological and Hydrological Institute (SMHI).

– Regions like northern Sweden and Finland have vast, uninhabited forest areas. If we can detect fires within an hour, it could really help emergency services locate them before they grow too large.

Facts

Two satellites in a single launch

Flex is a satellite equipped with a spectrometer capable of detecting the faint light emitted by plants during photosynthesis, with a resolution of 300 by 300 meters.

Sentinel-3C is part of the European climate service Copernicus; its satellites orbit over the poles, gathering a wealth of data. It is the third satellite in the Sentinel-3 series (following 3A and 3B), and its instruments measure sea levels, color, and temperature.

The satellites' central computers come from Beyond Gravity in Gothenburg, which also manufactured a data link antenna for Flex. The satellites are being launched on a Vega-C rocket from ESA’s launch site in Kourou, French Guiana, as planned, during the night leading up to September 15.

Sources: ESA, Beyond Gravity