Data Support provides popular reanalysis data
Researchers use the data to do new science. . .
 DSS staff
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by Nancy Dawson In 1998, SCD's Data Support Section completed preparing and correcting 50 years of data from the world's surface and upper-air observations. Data Support then sent the 1948-1997 data to the National Centers for Environmental Prediction (NCEP) for reanalysis, which was done for every six hours at 28 vertical levels. To prepare the data, Data Support staff tracked down and corrected errors in existing datasets and located sources for older observational data. "Before 1966, data may be sparse, incomplete, inaccurate, or missing altogether," says staff member Dennis Joseph. "After 1966, the datasets are pretty good." To supply missing data, staff located and cleaned up old data tucked away in archives and requested additional data from colleagues in other countries. Data Support staff also worked on the Comprehensive Ocean Atmospheric Data Set (COADS) project to update the world's surface ocean observations. The COADS data were then used as part of the reanalysis project. Data Support staff also improved the information on the location and elevation of the observation stations by comparing various catalog listings, recalculating elevations from the actual upper-air observations, gathering information on when the observation stations moved, and poring over world atlases. After NCEP reanalyzed the data, it was shipped back to NCAR, where Data Support staff made the data available to users directly from NCAR's Mass Storage System (MSS), on CDs and tapes, and for small amounts, over the Internet. "The reanalyzed data define the upper-air climate of the world for this 50-year period and are used for comparisons in climate models," says Roy Jenne, Data Support Section manager. "Users want to use the data immediately to update their models or do new science." The data are popular. Between January 1995 and August 1998, 12,542 gigabytes of NCEP/NCAR reanalysis data were accessed from the MSS or sent out on tapes and CDs. The Data Support Section continues to analyze and correct datasets and gather more information on the locations and elevations of observation stations. Their data will be fed into two upcoming projects: the European Centre for Medium-range Weather Forecasts data reanalysis for 1957-2000 and the refined NCEP data reanalysis for 1948-2002. |
