Florida Straits transport analysis

[atb299]

Florida Straits transport is significantly weaker than observed:

• Compute Florida Straits transports for all simulations: NPD, R-Evo1, GO8p7{h,m}, SE-NEMO
• Analyse velocities - is transport moving east of Bahamas, or is it weakening?
• Fix the problem

[atb299]

Velocity through FS from the NPD eORCA025 simulation:

[atb299]

There's a T and S change with vertical structure that appears in the NPD simulation:

I expect I'll find similar changes in the other simulations.

[jdha]

[jdha]

I'll do this properly later - but you can see that it's similar to the NPD structure

[jbkajtar]

Here are some findings for eORCA025-RAPID12-RAPID36:

Edit: updated depth coordinate for vo

[atb299]

It seems that the FS and Antilles transports both reduce in the models we've looked at. The DWBC seems to increase in the coarser (1/4) resolution models. All the models have the same common origin and forcing, so I guess the similarity is no real surprise. So I guess the question is what causes the reduction in the FS and Antilles transports? Is it drift in the T and S, or due to the forcing, or something else?

I found https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018jc014836, which looks like a good description of the Antilles current in the last ~20 years.

[bablusinha]

yes don't know if you remember I compared the Antilles transports in the 1/36 model with the Meinen paper and it gets the structure and the variability quite well. So it seems to be the magnitude of the current that is mostly affected.

[bablusinha]

ps these pictures are very illuminating!

[atb299]

T, S and rho anomalies from the NPD eORCA025 simulation, plus same zoomed into the FS. I don't know why Metric gives rho on a different grid - need to look into that...

[atb299]

Looks like model forcing is a key controller here:

It still drops a bit after ~2004, but mainly in the FS. The change in the Antilles and DWBC are much smaller than in the JRA55-do forced simulation:

ERA5

JRA55