global change data
Department of Energy Releases Updated Greenhouse Gas Database
The U.S. Department of Energy's Carbon Dioxide Information Analysis Center (CDIAC) has released an updated data base from the global ALE/GAGE/AGAGE monitoring network (DB1001), which provides continuous high-frequency measurements of methane, nitrous oxide, several halogenated hydrocarbons, carbon monoxide, and hydrogen. This data base supports analyses and monitoring related to greenhouse gases and to the Earth's ozone layer. The data were contributed by R. Prinn, Massachusetts Institute of Technology; D. Cunnold, Georgia Institute of Technology; P. Fraser, Commonwealth Scientific and Industrial Research Organization (CSIRO, Australia); R. Weiss, Scripps Institution of Oceanography (SIO); P. Simmonds and S. O'Doherty, Bristol University (United Kingdom); L.P. Steele (CSIRO); P. Salameh, SIO; and R.H.J. Wang, Georgia Institute of Technology. Data through March 2003 are now available for all five existing sites: Cape Grim, Tasmania; Point Matatula, American Samoa; Ragged Point, Barbados; Mace Head, Ireland; and Trinidad Head, California (stations also previously existed at Cape Meares, Oregon, and Adrigole, Ireland).

global change data
Estimates of CO₂ Emissions Released by Dept. of Energy's CDIAC
The U.S. Department of Energy's Carbon Dioxide Information Analysis Center (CDIAC) has released estimates of CO₂ emissions from fossil-fuel combustion and cement production, on global, regional, and national scales, for the years 1751-2000. The estimate for 2000 global CO₂ emissions, 6611 million metric tons of carbon, represents a 1.8% increase from 1999. These estimates, derived primarily from energy statistics published by the United Nations, were calculated using the methods of Marland and Rotty (1984). Cement production estimates from the U.S. Department of Interior's Bureau of Mines were used to estimate CO₂ emitted during cement production. Emissions from gas flaring were derived primarily from U.N. data, and were supplemented with data from the U.S. Department of Energy's Energy Information Administration (EIA) and CDIAC.

global change data
Landsat 7 Continues To Provide Earth Science Data
Landsat 7, one of the Nation's two earth remote sensing satellites, continues to provide useful images and data of the earth's surface despite a problem encountered with one part of the satellite. Attempts to fix the problem from earth have not been successful. "The problem involves a correction for the forward motion of the satellite," said R.J. Thompson, chief of the U.S. Geological Survey's EROS Data Center, from where the Landsat Program is managed. "But Landsat 7 continues to operate and send back degraded but still useful images and data that earth scientists use to track changes in the surface of our planet." Thompson said Landsat 7 is acquiring about 75 percent of the data of each image it was designed to provide. In the meantime, data from Landsat 5, launched in 1984, continues to send vital images of the U.S. and will continue to be used as a backup and to fill in gaps in coverage areas.

Landsat 5, launched in 1984, covers the entire earth's surface every 16 days and has continually served as a backup for the technologically advanced Landsat 7 since its 1999 launch. Landsat 5 has performed far beyond its three-year design lifetime, and sent hundreds of thousands of 100-mile by 100-mile land-surface images to U.S. and international ground receiving stations. The Landsat Program is the longest running program providing vital images of the Earth's surface from space. The first Landsat satellite was launched in 1972 and since then, Landsat satellites have been providing a constant stream of moderate-resolution images. In 1999, the Landsat Program took a giant leap forward technologically with the launch of Landsat 7. The instruments on the Landsat satellites have acquired more than 4 million images of the surface of the planet, providing a unique resource for scientists who study agriculture, geology, forestry, regional planning, education, mapping and global change research.

The Energy Department's Atmospheric Radiation Measurement (ARM) Program now offers CO₂ flux estimates from its Southern Great Plains (SGP) site in Oklahoma. Located on the 60 m tower at the ARM Central Facility (CF), the flux measurement system obtains CO₂ and H₂O densities using an infrared gas analyzer, and wind speed and direction and virtual temperature using a sonic anemometer. From these measurements, half hour to four hour mean flux estimates are calculated at 2, 4, 25, and 60 m above the ground. The concentrations and flux estimates from the continuous monitoring at the SGP site are available at the ARM Archive.

Dataset database now searchable on the web
This catalog provides a comprehensive list of global change-related data sets made available during 2001 from federal agencies. The fifth in a series of yearly publications, this catalog represents an important step in the interagency process of making data and information from the U.S. Global Change Research Program available to researchers, the commercial world, policy makers, and the public. This 2001 edition is now stored in a searchable database. To search the database, click here.

On-line editions of Newly Available Agency Data Sets That Are Significantly Global Change Related are available for 1997, 1998, 1999, 2000, and 2001.