Science/Medicine : Tracking Plant Life--Via Satellite

A UC Davis scientist is helping test a new technology called imaging spectrometry to study plants--as in deserts and jungles--via satellite.

The approach should provide the most detailed views yet of the plant communities that make up the earth’s greenery--indicating how they grow and how they react to environmental change, according to Susan Ustin, a physiological ecologist who is working in cooperation with other scientists at UC Davis and NASA.

For example, she said, a three-dimensional model of a rain forest can be re-created from the ground up to the canopy, using imaging spectrometry and microwave data. Physical cycles like aging, growth, water use and leaf movement can be monitored.

The sensors, independent of geography and climate, will replace years of field work, Ustin said.

Imaging spectrometry detects invisible as well as visible electromagnetic radiation reflecting from the Earth. Every object, because of chemical composition, emits a unique pattern of radiation, which the sensors detect.

Past Earth survey satellites could handle up to seven radiation energy ranges. But the new imaging spectrometers handle more than 200.

In tests in the Owens Valley and an orchard in California’s Central Valley, with sensors on Landsat, the images produced vivid, colorful pictures, producing three to four times the information previously available.

Fully developed, the technology--expected to be incorporated into NASA’s proposed space stations--will enable researchers to better oversee global health by understanding the impact of human activities like destroying rain forests and causing pollution.

“Ultimately, the habitability of the Earth depends on what happens to its vegetation,” Ustin said.