NASA satellite datasets aid the creation of national biomass and carbon dataset

NASA satellite datasets aid the creation of national biomass and carbon dataset

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Scientists at the Woods Hole Research Center in U.S. are producing a high-resolution “National Biomass and Carbon Dataset” for the year 2000 (NBCD2000), the first ever inventory of its kind. Through a combination of NASA satellite datasets, topographic survey data, land use/land cover data, and extensive forest inventory data collected by the U.S. Forest Service, this “millennium” dataset will serve as an invaluable baseline for carbon stock assessment and flux modeling in the U.S. Funding for this project is provided by NASA’s Terrestrial Ecology Program for a habitable Earth, seeking to conserve and sustain forests, soils, water, and energy by demonstrating their value to human health and economic prosperity. The Center sponsors initiatives in the Amazon, the Arctic, Africa, Russia, and North America.

The NBCD2000 project draws on vegetation canopy height estimated from digital elevation data collected during the 2000 Shuttle Radar Topography Mission, which mapped 80 percent of the Earth’s land mass with a radar instrument, producing the most complete digital surface map of Earth. In combination with the National Land Cover Database 2001(NLCD2001) and the National Elevation Dataset (NED), both generated by the U.S. Geological Survey, and forest survey data from the U.S. Forest Service, a high-resolution database of circa-2000 vegetation canopy height, aboveground biomass, and carbon stocks for the conterminous United States will be generated, providing an unprecedented baseline against which to compare data products from the next generation of advanced Earth observing remote sensing platforms.

In the NBCD2000 initiative, data will be analyzed in 60 ecologically diverse regions, termed “mapping zones”, which cover the entire conterminous United States. Within each mapping zone data from the space shuttle are combined with topographic survey data from the NED to form a radar-measured vegetation height map. Subsequently, this map is converted to estimates of actual vegetation height, biomass, and carbon stock using survey data from the U.S. Forest Service and ancillary data sets from the NLCD2001 project, which uses the same mapping zones. The NLCD2001 provides crucial input to the NBCD2000 project for stratification of the calibration/conversion process by providing land use/land cover and tree cover data sets.

The first phase of the project is beginning now and it is expected to conclude in early 2007. The first mapping zone targeted by the study is in central Utah, where the current production of the NLCD2001 is completed and where high quality NED data are available. The following results and products will be delivered at the end of phase one for each of the six mapping zones:

1) An ArcGIS/FGDC compatible database with vector layers and an associated attribute table, the modeled mean estimates for height, aboveground biomass, and carbon stock, as well as spatial error and confidence measures which are based on the validation results.

2) Three 30 m-resolution raster layers corresponding to the modeled vegetation canopy height, aboveground biomass, and carbon stock, plus associated confidence layers for height and biomass.

3) A detailed metadata report containing the validation statistics together with all model statistics. The horizontal co-registration residuals and the “correction surface” used for vertical fitting of the SRTM and NED data sets will also be included.

4) A compilation of the final inversion models specific to each ecoregion (i.e., mapping zone), and vegetation structural group.

5) Various publications, presentations at the AGU and Carbon cycle science meetings.