The data are available as a suite of 2x2 degree tiles. Each tile contains 1km x 1km gridded values and is available as a netCDF file. The tile locations cover land areas from Mexico to southern Canada. Due to the convergence of the meridions, the grid size of each tile can vary.
DAYMET: Daily Sfc Weather and Climatologies
wget --limit-rate=3m http://daymet.ornl.gov/thredds/fileServer/allcf/2010/12296_2010/prcp.nc -O prcp.2010_12296.nc
I am pleased to announce a new version of the NCL join script for spatially merging Daymet NetCDF files. This version should be easier to use and more reliable than before. New features include:
- Multiple tiles can be efficiently joined in a single program run.
- Common grid point between tiles is no longer required.
- Missing 2-D coordinates in gaps between tiles are automatically filled in.
- New diagnostics to ensure correct spatial alignment are included.
- Support for larger output files is improved.
The most significant feature is infill of missing 2-D coordinates. Output from previous versions left zeros in portions of the 2-D coordinates, which made these files very difficult to use with some graphics systems such as NCL. This problem is now completely solved, thanks to a new supplemental coordinate file provided by Daymet/ORNL.
The new join script is identified as join.daymet.1226.ncl. It can be obtained from the updated documentation website: http://www.esrl.noaa.gov/psd/people/dave.allured/data/daymet/daymet.html
The script produces 4 netCDF files. Three associated with the ESMF regridding software: (i) a weight file which can be used to regrid other variables from the same tile; (ii) a 'SCRIP style' file containing a description of the source (daymet tile) grid; (iii) a 'SCRIP style' file containing a description of the destination rectilinear grid; and, (iv) a file containing the regridded variable.
If one wanted to interpolate to (say) a 4km x 4km grid, the variable 'dll' in the above script could be set to:
dll = 4.0/111.1since one degree of latitude is approximately 111.1 km/degree-of-latitude. For tile 12296, the result is a grid of size 56x56.