Environmental challenges: Measuring greenhouse gasses by satellite
Here’s a challenge: Figure out a way to measure atmospheric accumulations of greenhouse gasses anywhere in the world. It’s not the kind of thing you have to do everyday, but when the Japan Aerospace Exploration Agency (JAXA) wanted to find a way to do that task with a satellite, they approached ABB’s analytical devices unit to design the actual sensor to detect and measure greenhouse components.
The GOSAT (Greenhouse gases Observing SATellite) is scheduled to be launched in 2008 by JAXA and will enable Japanese scientists to study and measure greenhouse gases in support of the Kyoto protocol. This will help them determine compliance with requirements for developed nations to reduce greenhouse-gas emissions between 2008 and 2012.
The $10 million contract was awarded to ABB's Analytical Business Unit in Quebec in August 2005 by NEC Toshiba Space Systems, the primary mission instrument supplier to the GOSAT program. After less than two years, ABB has now delivered the special unit so it can be incorporated into the satellite and move the project into its next phase.
“We are delighted that one of our core applications, greenhouse gas measurements, will play an essential role in this system,” says Marc-Andre Soucy, Manager of ABB's remote sensing industry. “In addition, I am very proud of the project team which has designed one of the most efficient interferometers in space history, all within a tight timeframe."
The 15-person team included mechanical, electrical and software engineers (data processing), physicians, opticians and technicians. The new instrument incorporates some of the features of an ABB-built payload currently in operation on the satellite ACE/SciSat-1 that was developed for the Canadian Space Agency.
The Michelson interferometer of the Fourier transform spectrometer is a system that will collect and transmit global distribution in carbon dioxide and methane density. Following a cycle every 3 days, the satellite collects precise atmospheric measurements from 666 kilometers (more than 413 miles) above the earth. The measurements will be used to chart and evaluate atmospheric carbon dioxide and methane levels.
ABB’s measuring process takes advantage of the “spectral signature” of the molecules that carbon dioxide and other gases emit, making them easy to identify and measure with infrared technology. The ABB spectrometer uses infrared technology to “read” the signature and establish the density of the molecules. By taking the readings at different orbital points—latitude, longitude and altitude—profiles are created to establish concentration levels of each gas.
GOSAT is also important because the number of effective ground-based carbon dioxide observation stations has thus far been limited, mainly because they are poorly distributed throughout the world. “GOSAT will be the first observatory that will steadily and globally monitor greenhouse gases at 56,000 observation points every three days.” says Takashi Hamazaki, JAXA project manager. “Scientists will be able to combine global observation data sent from space with data already being gathered on land.”
—Edited by Peter Welander, process industries editor, PWelander@cfemedia.com , Control Engineering Weekly News