# ACCESS-coupled N48 for deep paleo

**URL:** <https://forum.access-hive.org.au/t/access-coupled-n48-for-deep-paleo/529>\
**Category:** Earth System\
**Tags:** palaeogeography\
**Created:** [3 March 2023 00:32 UTC](https://forum.access-hive.org.au/t/access-coupled-n48-for-deep-paleo/529 "2023-03-03T00:32:54Z")\
**Posts on this page:** 1\
**Showing post:** 34

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**Author:** ![dkhutch](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.access-hive.org.au/dkhutch/32/510_2.png) [@dkhutch](https://forum.access-hive.org.au/u/dkhutch)\
**Post date:** [16 June 2023 05:55 UTC](https://forum.access-hive.org.au/t/access-coupled-n48-for-deep-paleo/529/34 "2023-06-16T05:55:37Z")

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To turn an ocean grid cell into a land point (from the ocean model point of view): the main things you need to do are  
(1) edit the **topog.nc** , i.e. set an exisiting non-zero depth cell to zero.  
(2) Re-run a tool that creates the **grid\_spec.nc** input file based on the edited topog.nc.  
I have outlined a procedure to do this for the GFDL CM2.1 model, [in step 1 of this wiki](https://forum.access-hive.org.au/t/adapting-gfdl-cm2-1-coupled-model-for-deep-time-paleoclimate-experiments/826). Since ACCESS-ESM uses the same ocean, the procedure is basically the same (for the ocean model side). You will just have to use the ACCESS-ESM grid input files rather than the ones I used in my example (it’s a different resolution).

The slight complication here is that MOM5 can accept the grid\_spec.nc input file using the “old method”, where all grid variables are included in grid\_spec.nc, or the “new method”, where grid\_spec.nc specifies the grid files through **mosaic** files that point to individual grid inputs for each model component.

I have noticed that ACCESS-ESM1.5 uses the “old method”… whereas the tool I specified creates these inputs using the “new method”, i.e. using mosaic input files. It is entirely possible to go between the two methods of creating grid\_spec.nc, and I’m endeavouring to do this as a test case. I am going to try to do that… will report back to this post when I have more info.

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