NASA Satellite Adds Carbon Dioxide to its Repertoire
A NASA-led team has expanded the growing global armada of remote sensing satellites capable of studying carbon dioxide, the leading greenhouse gas driving changes in our climate.
PASADENA, Calif. -- A NASA-led research team has expanded  the growing global armada of remote sensing satellites capable of studying  carbon dioxide, the leading greenhouse gas driving changes in Earth's climate.The newest addition is the Tropospheric Emission  Spectrometer (TES) instrument on NASA's Aura spacecraft, launched in 2004. TES  measures the state and composition of Earth's troposphere, the lowest layer of  Earth's atmosphere, located between Earth's surface and about 16 kilometers (10  miles) in altitude. While TES was not originally designed to measure carbon  dioxide, a team led by Susan Kulawik of NASA's Jet Propulsion Laboratory,  Pasadena, Calif., has successfully developed and validated a TES carbon dioxide  tool.Kulawik's team analyzed three years of carbon dioxide data  from TES and compared them to other carbon dioxide data sources. These sources  included the Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua  spacecraft, aircraft and ground station samples, and two National Oceanic and  Atmospheric Administration carbon dioxide research tools: GLOBALVIEW-CO2 and  CarbonTracker. The TES data were found to be in good agreement with the other  data. The TES study appears in the journal Atmospheric Chemistry and Physics.Kulawik says TES data may be able to help significantly  reduce uncertainties in annual regional estimates of where carbon dioxide is  being created (sources) and where it is being stored (sinks)."It's easy to see why you need measurements near  Earth's surface, but TES measurements in the region of the atmosphere where  carbon dioxide gets transported around the globe are also key to understanding  carbon dioxide sources and sinks," Kulawik said.Study co-authors Ray Nassar and Dylan Jones of the  University of Toronto, Ontario, Canada, found that TES data can reduce -- by  approximately 70 percent -- uncertainties in estimates of how much carbon  dioxide is being released and stored in South America's tropical rain forests  and Africa's grasslands. These include the Amazon, Congo and surrounding  savannahs."These regions have a major influence on the global  carbon cycle," said Jones. "The new carbon dioxide data from TES will  help scientists reduce uncertainties in our understanding of carbon dioxide,  particularly in tropical regions, where there are currently very few surface or  aircraft measurements."Carbon dioxide is the most important human-produced  greenhouse gas. Its current global average concentration in Earth's atmosphere  is about 389 parts per million by volume, increasing by about two parts per  million each year. This concentration varies seasonally and by hemisphere.  Estimates are challenging, as it varies by less than two percent globally in  the mid-troposphere.Currently, about 55 percent of human-produced carbon dioxide  remains in the atmosphere; the rest is stored in the ocean and by land plants,  but exactly where remains a mystery. Recent studies have shown carbon dioxide  emissions from fossil fuel combustion have been increasing faster than  predicted, while the southern hemispheric oceans' capacity for storing carbon  dioxide may be diminishing. Scientists want to better understand carbon dioxide  sources and sinks so they can more reliably predict future atmospheric carbon  dioxide levels, assess the impact of land use changes on atmospheric carbon  dioxide, develop mitigation strategies and verify international treaties.The new TES carbon dioxide data complement the available  international space-based resources for measuring carbon dioxide. These include  AIRS; Envisat's European Scanning Imaging Absorption Spectrometer for  Atmospheric Chartography (SCIAMACHY); the European MetOp Infrared Atmospheric  Sounding Interferometer (IASI); and the Japan Aerospace Exploration Agency's  Greenhouse gases Observing Satellite (GOSAT). The Orbiting Carbon Observatory  mission, NASA's first spacecraft dedicated to studying carbon dioxide and its  sources and sinks, was lost in a launch vehicle mishap in February 2009. It is  currently being rebuilt for a planned launch in 2013.TES will measure carbon dioxide in the troposphere at  altitudes between 2 and 8 kilometers (1.2 to 5 miles), with peak sensitivity at  around 5 kilometers (3.1 miles). It will produce carbon dioxide products at  latitudes between 40 degrees south and 45 degrees north. The team expects to  release daily and monthly TES carbon dioxide data products to the public  starting this July.Other institutions participating in the study include the  National Institute for Environmental Studies, Tsukuba-City, Ibaraki, Japan; the  Meteorological Research Institute, Tsukuba-City, Ibaraki, Japan; Lawrence  Berkeley National Laboratory, Berkeley, Calif.; and NOAA's Earth System  Research Laboratory, Boulder, Colo.For more on the Tropospheric Emission Spectrometer, visit:http://tes.jpl.nasa.gov.JPL is managed for NASA by the California Institute of  Technology in Pasadena.