The National Snow and Ice Data Center at the University of Colorado at Boulder will soon be distributing information collected by the Terra satellite, NASA聮s premier Earth Observing System spacecraft launched in December 1999.
Terra is the first satellite to monitor how Earth聮s atmosphere, land, ocean, snow and ice cover, solar radiation and life influence the planet on a daily, global scale, according to NASA officials. Carrying five instruments, Terra is giving scientists a comprehensive view of Earth as a system and monitoring its long-term health.
One instrument, the Moderate Resolution Imaging Spectroradiometer, views the entire Earth surface every one to two days, gathering high-quality data in 36 spectral bands, many invisible to the human eye. The wide spectral range and high resolution will allow for the production of the most accurate global snow maps ever produced, said NSIDC researcher Greg Scharfen.
"Since annual runoff from mountain snowpack contributes to streamflow and recharges groundwater over wide areas of the mid-latitudes -- supplying water reserves for more than a billion people worldwide -- snow maps are valuable in the short-term to water resource managers and planners," said Sharfen. "In the long-term, consistent global records of snow and sea-ice extent are valuable to climate researchers. "
Although the MODIS instrument will be a boon to scientists, the sheer volume of data generated poses a formidable challenge for archive centers like NSIDC, he said.
"Preparations for ingesting and archiving the volumes of MODIS data have been underway here since 1990, as computer systems were ramped up to accept about eight gigabytes of data per day initially, and between 16 and 20 gigabytes per day under full production about a year from now," said Sharfen. NSIDC will be able to deliver a like quantity of data to users per day, he said.
One gigabyte equals about 1 billion bytes. For comparison purposes,, the entire second edition of Oxford English Dictionary made up of 20 volumes and 59 million words, takes up approximately 540 million bytes or 540 megabytes of electronic storage, he said.
The Boulder facility is one of eight NASA data archives, each specializing in a particular science discipline. Only four of the NASA archives will house data from the Terra spacecraft. If all goes well, the Terra spacecraft is expected to download 190 gigabytes of data per day from all five instruments onboard.
Snow and Ice data from MODIS are anticipated to be available beginning late summer 2000. For more information, see .
The National Snow and Ice Data Center is part of the Cooperative Institute for Research in Environmental Sciences, a joint program of CU-Boulder and the National Oceanic and Atmospheric Administration.