Top of Mount Fuji helping the study of global warming

Observations being made atop majestic Mount Fuji are helping to map a clearer picture of global warming.

Automatic monitoring equipment on the 3,776-meter summit is being used to measure carbon dioxide levels. It is part of a project by the National Institute for Environment Studies in Tsukuba, Ibaraki Prefecture, to record the movement of the heat-trapping gas carried by winds from China and elsewhere in Asia.

The equipment was set up in the Mount Fuji observatory of the Japan Meteorological Agency. It went into full operation this summer.

Researchers are keen to monitor carbon dioxide levels in the air year-round to get a better fix on the mechanism that creates global warming.

The equipment was developed to enable researchers to record data at extremely low temperatures. Temperatures inside the Mount Fuji observatory drop to below minus 20 degrees.

The equipment is installed with 100 batteries that can provide power even under severe weather conditions. It must be maintained at at least zero degrees for accurate observations.

The equipment has a margin of error of 0.3 parts per million, or 0.3 gram of carbon dioxide for every million grams of air.

In July and August, the hottest summer months, the equipment relies on other power sources and recharges the batteries.

The data, recorded once a day, is transmitted to the institute via satellite.

The institute's Center for Global Environmental Research began the development of monitoring equipment in 2007. Researchers started carbon dioxide observations with the use of prototype equipment on a trial basis in 2009.

But it was problematic because researchers had to manually work on discharging and charging batteries in the initial months.

Atsuko Sunaga, a junior research associate at the Global Carbon Cycle Research Section at the institute's Center for Global Environmental Research, said it was "tough" work during harsh weather conditions.

"The air was thin and one could develop altitude sickness," she said.

Sunaga and her colleagues updated the existing equipment so that simply flicking a switch got the job done. This paved the way for the institute to make observations with the new equipment throughout the year.

The institute has been keeping track of long-term fluctuations in the density of carbon dioxide in a broad area to predict how global warming will unfold in the future.

One focus is to gauge the impact on the environment caused by carbon dioxide carried by winds from China and other Asian countries.

The project also involves observations by private-sector aircraft and freighters traveling between Japan and the United States as well as Europe. The Greenhouse Gases Observing Satellite, known as Ibuki (breath), is also part of the project.

The observation of carbon dioxide at ground level started in 1993 at Haterumajma island in Okinawa Prefecture. Two years later, observations got under way at Ochiishi Point in Nemuro, a city in Hokkaido.

At Haterumajima, researchers observed carbon dioxide being carried by winds from the north. The gas is believed to have been emitted by factories in industrial areas of Shanghai and elsewhere in China.

Data obtained at Ochiishi Point reflects the impact of photosynthesis occurring in Siberian forests.

The Mount Fuji project marked the first observation point midway between the two.

There is an added advantage to making checks on the mountain.

Data recorded at any point higher than 3,000 meters helps researchers to determine the impact of carbon dioxide carried by winds from China without having to consider the effects of the same gas created in Japanese cities.

It is also easier to compare figures on Mount Fuji and Mauna Loa, a mountain in Hawaii, because the two peaks are of similar height.

A comparison of figures obtained on Mount Fuji since 2009 and Haterumajima island show that the average concentration of carbon dioxide at Haterumajima in winter is higher than that of the gas on Mount Fuji in the same season.

Researchers believe that the higher reading has a bearing on carbon dioxide coming from China.

"We are expecting to gather data on carbon dioxide and the spread of the gas in East Asia by comparing data on Mount Fuji, where continuous observation has been made possible, with that of Haterumajima island, Ochiishi Point and Hawaii," Mukai said.