Merge pull request #428 from PCMDI/2026-03-20-email-update

Add 2026-03-20 email update

Author: znichollscr

changelog/428.docs.md

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+Added 2026-03-20 IPO email update

docs/forcings-email-archive/2026-03-20.md

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+# 2026-03-20 update
+
+There is an update to the nitrogen deposition data (new data is published under source ID `FZJ-CMIP-nitrogen-2-0`).
+However, if you already have simulations that use the previous version (source ID `FZJ-CMIP-nitrogen-1-2`), you do not need to re-run.
+Further details below and at [https://input4mips-cvs.readthedocs.io/en/latest/dataset-overviews/nitrogen-deposition/](https://input4mips-cvs.readthedocs.io/en/latest/dataset-overviews/nitrogen-deposition/).
+
+As a result of an issue being found ([#425](https://github.com/PCMDI/input4MIPs_CVs/issues/425)),
+a new version of the nitrogen deposition forcing has been released.
+
+* Modelling centres who have already run their piControl and/or historical simulations do not need to re-run.
+* Modelling centres who have not yet started their piControl and/or historical simulations should use the `FZJ-CMIP-nitrogen-2-0` data.
+
+For further details about the error and recommended action,
+please see the nitrogen deposition dataset page [https://input4mips-cvs.readthedocs.io/en/latest/dataset-overviews/nitrogen-deposition/](https://input4mips-cvs.readthedocs.io/en/latest/dataset-overviews/nitrogen-deposition/).
+
+If any modelling centres run piControl and/or historical simulations with both the `FZJ-CMIP-nitrogen-2-0` and `FZJ-CMIP-nitrogen-1-2` forcing,
+these simulations would be of interest to the Forcings Task Team.
+(Underlying pull request: [#427](https://github.com/PCMDI/input4MIPs_CVs/pull/427))

docs/forcings-email-archive/SUMMARY.md

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 - [Overview](index.md)
+- [2026-03-20](2026-03-20.md)
 - [2026-02-26](2026-02-26.md)
 - [2026-02-24](2026-02-24.md)
 - [2026-02-16](2026-02-16.md)

docs/forcings-email-archive/index.md

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 Here we provide an archive of emails with updates about the forcings sent by the CMIP International Project Office (IPO).
 
+- [2026-03-20](2026-03-20.md)
 - [2026-02-26](2026-02-26.md)
 - [2026-02-24](2026-02-24.md)
 - [2026-02-16](2026-02-16.md)