New NASA Map Reveals Patterns Of Tropical Forest Carbon Storage

Steve Cole

Headquarters, Washington

 

Alan Buis

Jet Propulsion Laboratory, Pasadena, Calif.

WASHINGTON -- A NASA-led research team has used a variety of NASA satellite data to create the most precise map ever produced depicting the amount and location of carbon stored in Earth's tropical forests. The data are expected to provide a baseline for ongoing carbon monitoring and research and serve as a useful resource for managing the greenhouse gas carbon dioxide.

The new map, created from ground- and space-based data, shows for the first time the distribution of carbon stored in forests across more than 75 tropical countries. Most of that carbon is stored in the extensive forests of Latin America.

"This is a benchmark map that can be used as a basis for comparison in the future when the forest cover and its carbon stock change," said Sassan Saatchi of NASA's Jet Propulsion Laboratory in Pasadena, Calif., who led the research. "The map shows not only the amount of carbon stored in the forest, but also the accuracy of the estimate." The study was published May 30 in the Proceedings of the National Academy of Sciences.

Deforestation and forest degradation contribute 15 to 20 percent of global carbon emissions, and most of that contribution comes from tropical regions. Tropical forests store large amounts of carbon in the wood and roots of their trees. When the trees are cut and decompose or are burned, the carbon is released to the atmosphere.

Previous studies have estimated the carbon stored in forests on local and large scales within a single continent, but there existed no systematic way of looking at all tropical forests. To measure the size of the trees, scientists typically use a ground-based technique, which gives a good estimate of how much carbon they contain. But this technique is limited because the structure of the forest is extremely variable and the number of ground sites is very limited.

To arrive at a carbon map that spans three continents, the team used data from the Geoscience Laser Altimeter System lidar on NASA's ICESat satellite. The researchers looked at information on the height of treetops from more than 3 million measurements. With the help of corresponding ground data, they calculated the amount of above-ground biomass and thus the amount of carbon it contained.

The team then extrapolated these data over the varying landscape to produce a seamless map, using NASA imagery from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on NASA's Terra spacecraft, the QuikScat scatterometer satellite and the Shuttle Radar Topography Mission.

The map reveals that in the early 2000s, forests in the 75 tropical countries studied contained 247 billion tons of carbon. For perspective, about 10 billion tons of carbon is released annually to the atmosphere from combined fossil fuel burning and land use changes.

The researchers found that forests in Latin America hold 49 percent of the carbon in the world's tropical forests. For example, Brazil's carbon stock alone, at 61 billion tons, almost equals all of the carbon stock in sub-Saharan Africa, at 62 billion tons.

"These patterns of carbon storage, which we really didn't know before, depend on climate, soil, topography and the history of human or natural disturbance of the forests," Saatchi said. "Areas often impacted by disturbance, human or natural, have lower carbon storage."

The carbon numbers, along with information about the uncertainty of the measurements, are important for countries planning to participate in the Reducing Emissions from Deforestation and Degradation (REDD+) program. REDD+ is an international effort to create a financial value for the carbon stored in forests. It offers incentives for countries to preserve their forestland in the interest of reducing carbon emissions and investing in low-carbon paths of development.

The map also provides a better indication of the health and longevity of forests and how they contribute to the global carbon cycle and overall functioning of the Earth system. The next step in Saatchi's research is to compare the carbon map with satellite observations of deforestation to identify source locations of carbon dioxide released to the atmosphere.

For information about NASA and agency programs, visit http://www.nasa.gov.

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On May 21, 2011, Iceland’s Grimsvotn Volcano erupted, sending an ash plume 12 miles (20 kilometers) high and closing Keflavik Airport, Iceland’s largest. Ash fell on much of Iceland, with some areas pitch black at midday on the 22nd. This eruption is not expected to disrupt air travel as much as taht of Eyjafjallajokull in 2010 because the Grimsvotn ash particles are larger and settling out of the atmosphere more quickly.

This natural-color satellite image, acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Terra satellite, shows the towering ash plume at 1:00 p.m. local time. Beneath the ash plume, clouds cover much of the scene. Lingering snow is visible beneath the clouds to the northeast (upper left). Brown ash covers a portion of the Vatnajokull Glacier near the Atlantic coast (lower right).

Grimsvotn is Iceland’s most active volcano, but it hasn’t erupted so forcefully since 1902. The lava is basaltic, which typically erupts in non-explosive, Hawaiian-style eruptions. Grimsvotn is located beneath a glacier, however, and the interaction of melting ice with the lava can create an explosive eruption, at least in the initial stages.

Image Credit: NASA, GSFC, MODIS Rapid Response Team

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NASA's Terra satellite, part of the Earth Observing System of satellites, captured images of the damage path. An instrument aboard Terra called the Advanced Spaceborne Thermal Emission and Reflection Radiometer, or ASTER, was used to discern vegetation contrasts over the region.

"This is the first time ASTER data has been applied to such a massive outbreak of storms," said Gary Jedlovec, atmospheric scientist at Marshall Space Flight Center. "The usefulness of satellite information in providing improved accuracy along with damage assessment in severe weather events continues to evolve."

The tornado track signature observed by ASTER is seen as a disruption in the vegetation or other reflective surfaces over a region caused by tornado winds. Uprooted trees quickly stop the process of photosynthesis and change color -- this is easily detected by satellite.

However, detecting damage in areas outside of heavy forestland is challenging.

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The NASA image created by the Short-term Prediction and Research Transition or SPoRT project at the Marshall Space Flight Center in Huntsville, using data provided courtesy of NASA Goddard Space Flight Center, the Land Processes Distributed Active Archive Center, Japan’s Earth Remote Sensing Data Analysis Center, the Ministry of Economy, Trade and Industry, along with the Japan Research Observation System Organization.

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With its 14 spectral bands from the visible to the thermal infrared wavelength region and its high spatial resolution of about 50 to 300 feet, or about 15 to 90 meters, ASTER images Earth to map and monitor the changing surface of our planet. ASTER is one of five Earth-observing instruments launched Dec. 18, 1999, on Terra. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and data products.

The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping and monitoring of dynamic conditions and temporal change. Example applications are monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and, measuring surface heat balance.

Image Credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team

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This detailed, photo-like view of Earth is based largely on observations from MODIS, the Moderate Resolution Imaging Spectroradiometer, on NASA's Terra satellite. It is one of many images of our watery world featured in a new story examining water in all of its forms and functions.

Image Credit: NASA

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Like rivers of liquid water, glaciers flow downhill, with tributaries joining to form larger rivers. But where water rushes, ice crawls. As a result, glaciers gather dust and dirt, and bear long-lasting evidence of past movements.

Alaska's Susitna Glacier revealed some of its long, grinding journey when the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA’s Terra satellite passed overhead on Aug. 27, 2009. This satellite image combines infrared, red and green wavelengths to form a false-color image. Vegetation is red and the glacier's surface is marbled with dirt-free blue ice and dirt-coated brown ice. Infusions of relatively clean ice push in from tributaries in the north. The glacier surface appears especially complex near the center of the image, where a tributary has pushed the ice in the main glacier slightly southward.

Susitna flows over a seismically active area. In fact, a 7.9-magnitude quake struck the region in November 2002, along a previously unknown fault. Geologists surmised that earthquakes had created the steep cliffs and slopes in the glacier surface, but in fact most of the jumble is the result of surges in tributary glaciers.

Glacier surges--typically short-lived events where a glacier moves many times its normal rate--can occur when melt water accumulates at the base and lubricates the flow. This water may be supplied by meltwater lakes that accumulate on top of the glacier; some are visible in the lower left corner of this image. The underlying bedrock can also contribute to glacier surges, with soft, easily deformed rock leading to more frequent surges.

Image Credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science

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