NASA Satellite Measures Earth's Carbon Metabolism

This false-color map represents the Earth's carbon "metabolism"--the rate at which plants absorbed carbon out of the atmosphere in 2002. The map shows the global, annual average of the net productivity of vegetation on land and in the ocean. The yellow and red areas show the highest rates, ranging from 2 to 3 kilograms of carbon taken in per square kilometer per year. The green, blue, and purple shades show progressively lower productivity.

In honor of the Earth Day celebration, NASA scientists unveiled the first consistent and continuous global measurements of Earth's "metabolism." Data from the Terra and Aqua satellites are helping scientists frequently update maps of the rate at which plant life on Earth is absorbing carbon out of the atmosphere.

Combining space-based measurements of a range of plant properties collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) with a suite of other satellite and surface-based measurements, NASA scientists produce composite maps of our world's "net primary production" every 8 days. This new measurement is called net production because it indicates how much carbon dioxide is taken in by vegetation during photosynthesis minus how much is given off during respiration. Scientists expect this global measure of the biological productivity of plants to yield new insights into how the Earth's carbon cycle works, a critical step toward solving the climate change puzzle.

The rate of carbon fixation through photosynthesis is a basic property of life on planet Earth. It is the basis for capturing and storing the energy that fuels our world's living systems and forms the foundation of the food webs. The oxygen we breathe is a byproduct of this photosynthesis. According to its creators, these new net primary productivity maps provide a fascinating new insight into the intimate connection between the living world and the physical world.

"We are literally watching the global garden grow," says Steve Running, MODIS Science Team member and director of the Numerical Terradynamic Simulation Group at the University of Montana. "We now have a regular, consistent, calibrated and near-real-time measure of a major component of the global carbon cycle for the first time. This measure can also be the basis for monitoring the expansion of deserts, the effects of droughts, and any impacts climate change may have on vegetation growth, health, and seasonality."

For the complete article on the earth's carbon, go to: http://www.gsfc.nasa.gov/news-release/releases/2003/03-41.htm