Search found 7 matches

by dylanrs617
Mon Jun 16, 2025 7:44 pm
Forum: ROMS Discussion
Topic: Are negative temperatures possible with HSIMT?
Replies: 0
Views: 3766

Are negative temperatures possible with HSIMT?

I'm working with a student who has a regional model of the Beaufort Shelf. We plan on doing some advection scheme experiments to look at numerical mixing and I'm curious whether HSIMT can support negative temperatures. Maybe I'm misunderstanding, but there appears to be contradictory info about this ...
by dylanrs617
Tue Mar 25, 2025 5:46 pm
Forum: ROMS Discussion
Topic: LMD/KPP performance in river plume simulations
Replies: 3
Views: 13327

Re: LMD/KPP performance in river plume simulations

Thanks for sending this. I was unaware of the bug - but I am using COAWST v3.8, which has ROMS 4.1. I will need to see how difficult it is to git cherry pick the commit and deal with merge conflicts.

That said, I don't think GLS is overmixing in this case (recall I paired it with harmonic lateral ...
by dylanrs617
Sun Mar 23, 2025 8:09 pm
Forum: ROMS Discussion
Topic: LMD/KPP performance in river plume simulations
Replies: 3
Views: 13327

Re: LMD/KPP performance in river plume simulations

Just for an update, I found significant improvement with Richardson number smoothing paired with biharmonic mixing. See attached for a vorticity comparison with the same GLS simulation (that uses harmonic).

kpp_w_biharmonic_RI_smooth.png

RI_HORAVG Smooth Richardson number horizontally
RI ...
by dylanrs617
Fri Mar 21, 2025 3:51 pm
Forum: ROMS Discussion
Topic: LMD/KPP performance in river plume simulations
Replies: 3
Views: 13327

LMD/KPP performance in river plume simulations

Hi All,

I'm doing a model-model comparison of the Texas-Louisiana shelf with ROMS and MPAS-O. Our ROMS model is validated (Hetland 2017 JPO, Kobashi & Hetland 2020 OD) and normally uses k-omega or k-epsilon for vertical mixing with great success. The mean resolution is ~1.5 km. 30 vertical layers ...
by dylanrs617
Thu May 23, 2024 3:49 pm
Forum: ROMS Discussion
Topic: Question about Smagorinsky mixing coefficients
Replies: 0
Views: 10498

Question about Smagorinsky mixing coefficients

Hi All,

I'm doing some experiments with Smagorinsky viscosity/diffusion applied biharmonically along geopotential surfaces to explore its impacts on numerical mixing. In hmixing.F, I see that Bsmag is controlled by PecletCoef, which is equal to 1/12. Where does the 1/12 come from? It's unclear to ...
by dylanrs617
Tue Jul 25, 2023 7:43 pm
Forum: ROMS Discussion
Topic: DIAGNOSTICS_TS in step3d_t
Replies: 3
Views: 9623

Re: DIAGNOSTICS_TS in step3d_t

A little late, but I believe you're correct. Parker MacCready posted a thread about this about a decade ago, it gets at this issue as well. Took me too long to figure out myself until I discovered that thread, posting this to help aggregate.


I figured out the problem with my salt_rate test. salt ...
by dylanrs617
Tue Jul 25, 2023 7:20 pm
Forum: ROMS Discussion
Topic: Calculate tracer vertical diffusion coefficients offline?
Replies: 0
Views: 9635

Calculate tracer vertical diffusion coefficients offline?

Is it possible to calculate the vertical tracer diffusion coefficients "AKt" or "AKs" offline with model output? I'm using the GLS k-epsilon vertical mixing scheme for context and would appreciate if there's a way to compute them using the model equations.

I'd like to construct an offline ...