Japan's space agency will launch a satellite later this month to monitor greenhouse gases around the world, officials said yesterday, hoping the data it collects helps global efforts to combat climate change.

The Greenhouse Gases Observing Satellite (GOSAT), to be launched on Jan 21, will enable scientists to calculate the density of carbon dioxide and methane from 56,000 locations on the Earth's surface, the Japan Aerospace Exploration Agency (JAXA) said.

The coverage compares with just 282 land-based observation sites as of last October, said Takashi Hamazaki, manager of the 35 billion yen (US$372.9 million) JAXA project.

"To fight climate change, we need to monitor the density of greenhouse gases in all regions around the world and how their levels change," he said. "But at the moment, there are very few observation sites on land and they are concentrated in certain areas."

For example, sites monitoring greenhouse gases were lacking in developing countries, he said. GOSAT will cover those countries and also the atmosphere over seas.

Equipped with two sensors, GOSAT will track infrared rays from the Earth, which will help calculate the densities of the two greenhouse gases, because they absorb the rays at certain wavelengths.

The satellite will also pick up any sign of clouds, enabling it to process data only when the sky is clear. GOSAT, set to be in orbit for five years, will collect data once a month, with preliminary data expected to be ready for researchers in April or May.

Japan is under pressure to meet its 2008-2012 Kyoto Protocol target of cutting greenhouse gas emissions and is trying to be vocal in global talks on fighting climate change.

(China Daily via Agencies January 8, 2009)