# Lateral boundary issue in global simulation

**URL:** <https://nemo-ocean.discourse.group/t/lateral-boundary-issue-in-global-simulation/799>\
**Category:** v4.2.x\
**Created:** [12 December 2024 11:06 UTC](https://nemo-ocean.discourse.group/t/lateral-boundary-issue-in-global-simulation/799 "2024-12-12T11:06:29Z")\
**Posts on this page:** 8\
**Page:** 1

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**Author:** ![ttlin](https://avatars.discourse-cdn.com/v4/letter/t/7993a0/32.png) [@ttlin](https://nemo-ocean.discourse.group/u/ttlin)\
**Post date:** [12 December 2024 11:06 UTC](https://nemo-ocean.discourse.group/t/lateral-boundary-issue-in-global-simulation/799/1 "2024-12-12T11:06:29Z")

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Hi all,  
I am running nemo global model with ORCA05 resolution (720×510). I used the periodic boundary condition (jperio=4). The nemo version is 4.2.2.  
The problem is I found the anomaly values in the first and last column. In other words, the periodic boundary condition seems not working in my simulation. The v current and SST are attached below. DOES anyone have idea why it is like this? Thanks for all potential comments!

 ![image](https://global.discourse-cdn.com/free1/uploads/nemo_ocean/original/1X/2b5cff079a238fea2ab319ee86adaa3678a2c3cf.jpeg)  
 ![image](https://global.discourse-cdn.com/free1/uploads/nemo_ocean/original/1X/65f083779a814b320fafe3d7675ec08271157892.jpeg)

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**Author:** ![smasson](https://avatars.discourse-cdn.com/v4/letter/s/eb9ed0/32.png) [@smasson](https://nemo-ocean.discourse.group/u/smasson)\
**Post date:** [12 December 2024 15:30 UTC](https://nemo-ocean.discourse.group/t/lateral-boundary-issue-in-global-simulation/799/2 "2024-12-12T15:30:04Z")

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Which value do you have for `cyclic east-west` in the `ocean.output` file? `.true.` or `.false.`?

btw, for ORCA05, you must have `jperio = 6`

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**Author:** ![ttlin](https://avatars.discourse-cdn.com/v4/letter/t/7993a0/32.png) [@ttlin](https://nemo-ocean.discourse.group/u/ttlin)\
**Post date:** [12 December 2024 16:24 UTC](https://nemo-ocean.discourse.group/t/lateral-boundary-issue-in-global-simulation/799/3 "2024-12-12T16:24:12Z")

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Thanks for replying smasson! I changed jperio to 6. It works fine now.

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**Author:** ![smasson](https://avatars.discourse-cdn.com/v4/letter/s/eb9ed0/32.png) [@smasson](https://nemo-ocean.discourse.group/u/smasson)\
**Post date:** [12 December 2024 16:50 UTC](https://nemo-ocean.discourse.group/t/lateral-boundary-issue-in-global-simulation/799/4 "2024-12-12T16:50:27Z")

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This is very strange, jperio=4 or 6 are both defining an east-west periodicity. The difference between 4 and 6 concerns only the north pole folding (your northern line). This should make no difference in the southern Indian Ocean (where you had very strange features)…

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**Author:** ![ttlin](https://avatars.discourse-cdn.com/v4/letter/t/7993a0/32.png) [@ttlin](https://nemo-ocean.discourse.group/u/ttlin)\
**Post date:** [12 December 2024 17:46 UTC](https://nemo-ocean.discourse.group/t/lateral-boundary-issue-in-global-simulation/799/5 "2024-12-12T17:46:01Z")

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Hi smasson,

is it affected by the domain Netcdf file?  
I also changed Ni0glo to 722 and Nj0glo 511 in domain file, but my resolution keeps 720×510. Now, I am not sure which move make it works.

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**Author:** ![smasson](https://avatars.discourse-cdn.com/v4/letter/s/eb9ed0/32.png) [@smasson](https://nemo-ocean.discourse.group/u/smasson)\
**Post date:** [12 December 2024 20:46 UTC](https://nemo-ocean.discourse.group/t/lateral-boundary-issue-in-global-simulation/799/6 "2024-12-12T20:46:08Z")

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Changes in the domain size before and after (including) NEMO 4.2 are detailed here: [Migrating from 4.0.x to 4.2.x — NEMO release-4.2.2 documentation](https://sites.nemo-ocean.io/user-guide/migration.html)

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**Author:** ![ttlin](https://avatars.discourse-cdn.com/v4/letter/t/7993a0/32.png) [@ttlin](https://nemo-ocean.discourse.group/u/ttlin)\
**Post date:** [13 December 2024 11:56 UTC](https://nemo-ocean.discourse.group/t/lateral-boundary-issue-in-global-simulation/799/7 "2024-12-13T11:56:50Z")

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That is the case! Thanks smasson.

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**Author:** ![smasson](https://avatars.discourse-cdn.com/v4/letter/s/eb9ed0/32.png) [@smasson](https://nemo-ocean.discourse.group/u/smasson)\
**Post date:** [27 December 2024 15:40 UTC](https://nemo-ocean.discourse.group/t/lateral-boundary-issue-in-global-simulation/799/8 "2024-12-27T15:40:17Z")

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