# Files with lateral boundary conditions

**URL:** <https://nemo-ocean.discourse.group/t/files-with-lateral-boundary-conditions/903>\
**Category:** Uncategorized\
**Created:** [22 May 2025 17:52 UTC](https://nemo-ocean.discourse.group/t/files-with-lateral-boundary-conditions/903 "2025-05-22T17:52:52Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![qtqw](https://avatars.discourse-cdn.com/v4/letter/q/77aa72/32.png) [@qtqw](https://nemo-ocean.discourse.group/u/qtqw)\
**Post date:** [22 May 2025 17:52 UTC](https://nemo-ocean.discourse.group/t/files-with-lateral-boundary-conditions/903/1 "2025-05-22T17:52:52Z")

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I am trying to run NEMO with open boundaries, ln\_bdy = .true.  
I am going to use external boundary data, which means I have to create boundary files (bn\_ssh, bn\_u3d, bn\_v3d,…).  
Is there any examples of the boundary files?  
Which structure should they have?

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**Author:** ![jchanut](https://yyz2.discourse-cdn.com/free1/user_avatar/nemo-ocean.discourse.group/jchanut/32/9_2.png) [@jchanut](https://nemo-ocean.discourse.group/u/jchanut)\
**Post date:** [27 May 2025 09:54 UTC](https://nemo-ocean.discourse.group/t/files-with-lateral-boundary-conditions/903/2 "2025-05-27T09:54:37Z")

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Hi,

You can get inspiration from the [`AMM12`](https://sites.nemo-ocean.io/user-guide/cfgs.html#amm12) reference configuration that is shipped with NEMO. Boundary data files can be downloaded [here](https://gws-access.jasmin.ac.uk/public/nemo/sette_inputs/) (and all input data needed for a short run).  
There are also a number threads in this forum adressing this. See for instance [here](https://nemo-ocean.discourse.group/t/structure-of-open-boundaries/72).