Getting to the bottom of global warming--from space.

• Author: Jean, Grace V.
• Position: INSIDE SCIENCE + TECHNOLOGY

* The first of several satellites designed to monitor Earth's greenhouse gases has reached orbit and will begin collecting data in the coming months.

If all goes as planned, the Greenhouse Gases Observing Satellite for the next five years will track the amount of carbon dioxide and methane found in the planet's atmosphere and record the behavior and distribution of those gases in certain geographical regions.

The hope is that the data will illuminate how greenhouse gases are being emitted and absorbed by the Earth, which ought to help scientists determine what can be done to prevent global warming, says Takashi Hamazaki, the satellite's project manager at the Japan Aerospace Exploration Agency.

Increasing levels of carbon dioxide have been blamed for causing climate change. The gas, which occurs naturally and also is produced by man-made technologies, surrounds the Earth like a blanket and prevents reflected sunlight energy from escaping into outer space. The trapped infrared light heats up the planet.

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Scientists believe that the world's oceans, vegetation and soil absorb about half of the emitted carbon dioxide. But so far, they don't have much empirical proof of this phenomenon because of limited data.

Greenhouse gas data is routinely collected by 280 ground observation stations scattered worldwide, but they are concentrated mostly around Europe, Japan and the United States. Airplanes also carry sensors into the skies to collect additional data. With so few collection points, the information is not as accurate as scientists would like.

The atmosphere's carbon dioxide density dynamically changes, like a person's respiration, and it varies in different parts of the globe. The ideal way to monitor these variations holistically is via observation from space, scientists say.

The 18 billion yen GOSAT, as the satellite is nicknamed, will orbit the planet every 100 minutes using sophisticated sensors to measure greenhouse gases over the planet's entire surface at some 56,000 observation points. It can scan the entire globe in three days, Hamazaki says.

"I really hope to see the breathing of the Earth," he writes from Japan in response to emailed questions from National Defense.

Two onboard sensors, the Thermal and Near-infrared Sensor for Carbon Observation-Fourier Transform Spectrometer and the Cloud and Aerosol Imager, will work in tandem to evaluate the density of greenhouse gases. They will measure the infrared light...