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New Daymet Website Release

We are pleased to announce that a new release of the Daymet web site is planned for tomorrow, May 15th. The switch will happen around 1 pm EST. The current Daymet address, http://daymet.ornl.gov/ will redirect to the new web site. What's new:

  • The Daymet data set is now archived and distributed by the Oak Ridge National Lab Distributed Active Archive Center (ORNL DAAC). This includes continued support and enhancements of the Data Access sites and tools.
  • Daily mosaics of each Daymet variable by year will be available. Access to mosaic files will be through direct FTP or a THREDDS Data Server. The THREDDS Server includes a NetCDF Subset Service (2-GB file size limitation).

We hope that this is a seamless transition, but you may experience some down time as we switch over to the new site. We also hope that the new site and enhanced data sets continue to provide the data and tools that are important to your scientific, research, and educational endeavors. Your comments, suggestions, and questions are welcome. The ORNL DAAC is pleased to announce the release of Daymet: Daily Surface Weather Data on a 1-km Grid for North America, Version 2. Data set prepared by P.E. Thornton, M.M. Thornton, B.W. Mayer, N. Wilhelmi, Y. Wei, and R.B. Cook. This data set provides Daymet output data as mosaicked gridded estimates of daily weather parameters for North America, including continuous surfaces of day length, precipitation, shortwave radiation, snow water equivalent, maximum air temperature, minimum air temperature, and water vapor pressure. The Daymet data product was derived from selected meteorological station data by interpolation and extrapolation algorithms. The current data product covers the period January 1, 1980 to December 31, 2012. Data are available on a daily time step at a 1-km x 1-km spatial resolution in Lambert Conformal Conic projection with a spatial extent that covers the conterminous United States, Mexico, and Southern Canada as meteorological station density allows. Daymet mosaic data sets are available from the ORNL DAAC via two download mechanisms: 1) Data files may be obtained through DAAC search and order tools or directly from the FTP site. 2) Data can be subset spatially and temporally prior to downloading via the THREDDS (Thematic Real-time Environmental Data Services) Data Server. Data are provided in Climate and Forecast (CF) metadata convention compliant (version 1.4) netCDF file formats. Other tools are provided on the ORNL DAAC Daymet website that allow extraction of Daymet variable daily data as a text file for a single pixel or the download of gridded Daymet data in 2 degree by 2 degree tile data sets. The ORNL DAAC is a NASA-funded data center archiving and distributing terrestrial ecology and biogeochemical dynamics data. On May 6, 2014, we updated and posted for distribution a set of corrected Daymet Tiles. If you have downloaded Daymet data in the past, please check the Daymet Tiles or location/time for which you downloaded data against this list of updated tiles. The updates were necessary to correct a logical error in the routine that gap-fills nodata values for tmin and tmax in the input station data. On rare occasions, multiple input stations had the same multiple missing days causing errors in the regression routine. An update was applied that avoids this problem by adjusting the list of input stations during the gap-filling procedure. The list of updated tiles can be found at: http://daymet.ornl.gov/files/UserGuides/DaymetTileVersionReadme.txt from the web page http://daymet.ornl.gov/datasupport.html. The mosaic data sets that were just made publically available by the ORNL DAAC were generated from the most current sets of Daymet Tiles and include these updates.