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Multi-category and 3D fields in OASIS3-MCT

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Posted by Anonymous at October 10 2013

Hej

I have yet another OASIS user question for you today. As you may (or may not) know am I developing a new coupling interface for IFS in EC-Earth. One of the goals is to support both multi-category and multi-level fields. I'm aware that both can be considered special cases of the same thing, or that one could even map all multi-dimensional arrays to 1d vectors for coupling. However, as I want my coupling interface to be easy to use and expressive, I'd like to handle the cases as they are.

The simple question is: What would you suggest ? based on the functionnalities in OASIS3-MCT ?

Best regards,
Uwe.

Posted by Anonymous at October 11 2013

Dear Uwe,

The possibility to transfert bundle fields will be available around march 2015. A bundle field is a 3D field that allow to transfert for example different type of ice and avoid multiple arrays.
But there is no plan to introduce vertical interpolation in oasis3-mct.
This functionnality of exchanging bundle fields could be used to transfert 3D fields but each level would be treated as a 2D field with the same weights and addresses file for each level, with the possibility to calculate the 2D weights with oasis3-mct.
There is a functionnality in oasis3-mct that allows to concatenate 2D fields with same grid and same interpolation and we must see during the implementation of the bundle fields if this possibility can also be choosen by the user when exchanging the bundle fields (for opitimization).

Best regards,
Laure

Posted by Anonymous at October 12 2013

Hi Uwe,

To complete Laure's answer:
What is not clear in your mail is if you are looking for full 3D interpolation (including in the vertical) or only for multiple 2D horizontal interpolation (i.e. for each category or each level).
If you are only looking for multiple 2D horizontal interpolation, then we agree that multiple-category and multiple-level fields can be treated the same as bundle field and as Laure writes, this is planned.
If you are looking for full 3D interpolation, this is already "possible" (as you know) if you treat your 3D field in a 1D vector and use this 1D space to describe your local partitions and your weights-and-address file. You would have to generate this W&A file offline with something else than oasis (even if it is possible at one point that we include the possibility in oasis to generate a W&A file combining 2D horizontal interpolation with a simple linear vertical interpolation).
But besides this, we have no plan to fully support 3D fields, expressed as 3D fields and requiring full 3D interpolation; form what we know the vertical interpolation can be very complex as it will usually depend on the evolution of the vertical coordinate on the source and target sides.
So we hope this helps and let us know if you have further questions/remarks!
Regards,
Sophie
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