Hello, I have been troubleshooting a regional model for a while and would appreciate some ideas/input/expertise, if anyone is able and willing.
Aim: Regional model of Patagonian shelf
What I'm doing and why
- Telemac-2D: have used before without issue, but not in this region.
- I am applying the model to various palaeo-timeslices, and so it is a big computational task
- First, I sort my domain and model out for TPXO forcing, then I calibrate it for the present-day forcing from the lower resolution global model (which I use for the palaeo-forcing). I write my own boundary conditions file for this (h,u,v) and have successfully done so in another region.
Issues
- The tide does not propagate properly on the shelf - too much energy, and I suspect the system should be losing energy to the internal tide at the steeply-sloping shelf edge (particularly in the south).
- A smaller on-shelf only model of the Patagonian shelf works fine with TPXO9, high resolution forcing.
- However, when I take my boundaries off-shelf, the on-shelf tide is too energetic.
- I have to take my boundaries off-shelf because of the relatively lower resolution palaeo-tidal forcing that I need to use, to give it time to propagate sufficiently into my region of interest.
Options + specific questions
- Implement a baroclinic tidal dissipation parameterisation into the 2-d model (as per the work done here. It's still somewhat of a bodge job as buoyancy frequency in palaeo-timeslices unknown (but perhaps that issue would stand with Telemac-3D?). A lot of work if it might not fix the issue.
- Move to Telemac-3d - massively computationally expensive given the task ahead. Would it deal better with the steep continental slope?
- Try forcing the model internally and on the shelf (rather than at the boundaries) because my palaeo-tidal forcing dataset is reasonable on the shelf (but relatively low resolution, 1/8th deg). Is there a way to do this, with open boundaries at the edge of the model domain, and applying u,v,h internally?
- Something else I've not thought of.
- Give up and use a different model.
I'd be so grateful if anyone has any ideas or expertise they'd be willing to share. Because it's a palaeo-study it doesn't need to be perfect, it needs to be good enough (I'm working with large error bars!).
Many thanks in advance