Sample R code for reading EQUATES CMAQ output (netcdf files)

EQUATES
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Attached is some sample R code for accessing the 2017 EQUATES CMAQ daily average output netcdf file located in this Google Drive folder. The script shows how to:

  • open the netcdf file
  • extract the variable names and units, as well as the date and model grid information
  • read in the daily average PM2.5 data and calculate the annual mean PM2.5 for each grid cell
  • plot the annual average PM2. 5 data on a map

sample_Rcode_for_EQUATES_CMAQ_data.txt (5.0 KB)

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Here’s the same excellent example adapted to use the terra package instead of the rgdal and raster packages, and eliminating the M3 package which seems to have gone away.

sample_Rcode_for_EQUATES_CMAQ_data_revised_v2.txt (9.4 KB)

(revised to use the same sample NetCDF file as the original)
(revised again to fix a problem with the leaflet image)

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Wow, this is fantastic @DaveDixon. Thank you so much for sharing!! :grinning:

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Prof. Jenise Swall just updated the M3 package (14-Jun-2024) so I’ve updated the example to restore the M3 methods, which greatly simplify the code. I’ve also documented what changed with the leaflet example at the end.

sample_Rcode_for_EQUATES_CMAQ_data_rev1_v2.txt (5.9 KB)

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