Create open boundary conditions and initial config.

[AndyHoggANU]

Use same "cookie-cutter" strategy as mom6-panan to create open boundary conditions from a single RYF year of ACCESS-OM2.

For topography, we should begin with ACCESS-OM2-01 topography, before pushing to 1/20°using etopo data.

[angus-g]

Thanks for getting this started! Do you have any suggestions for the forcing dataset? I guess we can start with daily boundary forcing like we have already, is there a year of daily T, S, U, V (and maybe eta)?

[AndyHoggANU]

I think for the first iteration we should do exactly as we did for mom6-panan.
That is, the surface forcing is JRA-55-RYF9091 and the boundary forcing is taken from year ~186 of the ACCESS-OM2-01 spinup. Do you still have the old scripts for which dataset you derived the boundary forcing for those runs? If not, ping me and I will figure out a good run to use. If we don't have one, I can run for another year with daily output.

[angus-g]

I do have the scripts (they're in https://github.com/COSIMA/mom6-panan), but I thought there was something about the input data disappearing — but it's just that the non-bit-groomed output isn't available. I don't think that's an issue, so I can go ahead and cut out the forcing.

[ChrisC28]

Hi all,
Thanks for getting this started.
As a first step, RYF (both surface and boundary) is fine. I'm completely agonstic about the year to use. However, I'd like to play around with the conditions myself at some point.
I'm assuming the scripts in https://github.com/COSIMA/mom6-panan/scripts are where I can see how this is done?

[angus-g]

That's right. I've got a bit of a description of the process in this document too:
MOM6 Panantarctic.md

[ChrisC28]

Do you make use of the Raphael Dussin's "brushcutter" stuff? I ask only because he has a number of example, although nothing seems to have been updated since 2017.

[angus-g]

I originally tried using it, but it wasn't suitable for our input data, and I think maybe the interpolation didn't work for scaling up to 1/20°

[ChrisC28]

Hi all,
Has there been any progress? Anything I can do to help out at this stage?

[AndyHoggANU]

We discussed this last week - I think the consensus was that @angus-g would shortly get into his code and produce some open BCs for us ... but I don't think we have moved too far on it yet. Angus, let us know ...

[angus-g]

This has taken me a little longer than anticipated: my previous scripts didn't scale up too well to 4 boundaries, and there was a lot of manual data massaging for panan that I didn't reincorporate to the scripts. That's all fixed now, and I have a set of boundaries and a configuration generated, which I'll commit soon. At the moment I'm running into a too-high SSH (at 294 locations):

WARNING from PE    52: Extreme surface sfc_state detected: i=  74 j= 306 lon=-208.650 lat= -23.7  
40 x=-208.650 y= -23.740 D= 1.0433E+01 SSH= 2.0153E+01 SST= 2.4220E+01 SSS= 9.8536E-03 U-= 0.000  
0E+00 U+= 7.1118E-01 V-= 0.0000E+00 V+= 3.7707E-02

They seem to be located on the coast, but I can't see any inlets or anything that were causing problems for us before.

[ChrisC28]

Thanks for getting this running. Seems odd that the dodgy SSH values are on the coast given the large-ish distance to the boundaries. I can't think of a reason straight away why that would be the case in a regional model and not in a global model.

[ChrisC28]

Russ and I just had a quick chat about this issue. He thinks that the blow-up is likely occuring in the first couple of time-steps at a single location then propagating along the coast (a "nonsense Kelvin wave"). Any chance you could run the model forward for 20 time steps, producing SSH at every time step? Could be a way to identify where the problem is first occuring.

[angus-g]

You two and Andy are on the same wavelength! Here's the first pass at the SSH, although it seems to only be hourly even though I've asked for it every timestep (currently DT = 300). Pretty clearly points to the region where the extreme values are being detected!

[ChrisC28]

Where are you running these (ie. path to output)?