NADP > News > NADP Gradient Map Corrections

NADP Gradient Map Corrections

The following maps have been updated from their original files. If you need to see the original map gradient or PDF files, please contact NADP at napd@slh.wisc.edu to request the originals.

UPDATE 12/15/2025

Several mapping errors were corrected in 2025.

  • The 2016, 2017, 2019, 2020, 2021, 2022, 2023 deposition maps did not integrate the NADP precipitation data into the PRISM precipitation raster/grid file. All precipitation and subsequent deposition maps have been redrawn with integrated deposition data. This affects both NTN and MDN maps.
  • The 2019 and 2020 Total N deposition maps were drawn with incorrect Total N values. These maps have been redrawn with corrected Total N values.
  • The 2024 corrections for the 2016 and 2017 NH4, Total N, and SplusN maps used updated coordinates for IL78, OK00, and VA13. This caused the corrected maps to have small differences due to the positions. This correction reverts these three site coordinates back to their original 2016 and 2017 values.
  • The 2021 NTN concentration maps were drawn with a cell resolution of ~2km instead of ~4km. All 2021 NTN concentration maps have been redrawn with a cell resolution of ~4km. This does not affect the MDN maps.
  • All 2022 and 2023 maps were drawn with a cell resolution of ~2km instead of ~4km. All 2022 and 2023 maps have been redrawn with a cell resolution of ~4km. This affects both NTN and MDN maps.

UPDATE 11/07/2024

A data error produced incorrect NH4 concentration and deposition values in 2016 and 2017. The underlying data was corrected in 2023, and the subsequent maps were redrawn and posted on 11/7/2024. The maps affected are:

  • 2016 and 2017 NH4 concentration map
  • 2016 and 2017 NH4 deposition map
  • 2016 and 2017 total N deposition map
  • 2016 and 2017 S plus N deposition map