Hi All,
I recently configured ROMS for a hindcast simulation in Persian Gulf for the period of 2016-2019. The tidal input came from OTPS while the hydrodynamic and atmospheric forcing came from HYCOM analysis and GFS respectively. After completing the simulation I averaged the surface current at the Strait of Hormuz (please see the figure attached). As the Persian Gulf has inverse-estuarine circulation I was hoping to see flow coming in from Gulf of Oman (as tide should be neutralized after averaging U and V). However, instead of seeing the inflow at the surface I see eddy like structures on both sides of the strait. Could anyone please comment on why i see this eddies, and what i should do if I want to see/model the inflow at the surface? Does the vertical stretching function in grid making can make an impact here?
kind regards,
Mahmud
Average Surface Flow Through The Strait of Hormuz
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stevenmiguelfigueroa
- Posts: 22
- Joined: Mon Apr 20, 2020 12:49 pm
- Location: Chungnam National University
Re: Average Surface Flow Through The Strait of Hormuz
Nice result.
Maybe you can plot the average velocity from the perspective of an across-strait cross-section. If it is a two-layer circulation, you can integrate u across the area of each layer to get the upper and low layer integrated volume fluxes. I'm guessing the upper layer flow will be stronger as water is being lost by evaporation in the gulf?
Does your salinity data suggest an inverse circulation?
I've never seen it been done and could take some work, but maybe you could apply the fundamental theorem of vector calculus (Helmholtz theorem). It says you can decompose a sufficiently smooth vector field into a sum of a curl-free vector field and and a divergence-free vector field (streamlines). It would effectively filter out vorticity. Again, I've never heard of anyone doing that before though in oceanography.
Maybe you can plot the average velocity from the perspective of an across-strait cross-section. If it is a two-layer circulation, you can integrate u across the area of each layer to get the upper and low layer integrated volume fluxes. I'm guessing the upper layer flow will be stronger as water is being lost by evaporation in the gulf?
Does your salinity data suggest an inverse circulation?
I've never seen it been done and could take some work, but maybe you could apply the fundamental theorem of vector calculus (Helmholtz theorem). It says you can decompose a sufficiently smooth vector field into a sum of a curl-free vector field and and a divergence-free vector field (streamlines). It would effectively filter out vorticity. Again, I've never heard of anyone doing that before though in oceanography.
Re: Average Surface Flow Through The Strait of Hormuz
Hi Mahmud;
You have water entering the gulf in one side and leaving it in the other side. This horizontal shear can induce the eddy.
I have seen it when studding the Spencer Gulf, Australia but it is a much larger gulf. The inverse circulation in Spencer Gulf is in a geostrophic adjustment which results in water entering the gulf in on side and leaving it on the other side. But again, it is a much larger gulf. Have a look in Nunes and Lennon(1987) https://doi.org/10.1029/JC092iC05p05465
When you look at your salinity results can you see relative fresher water in on side compared with the other side?
A vertical section showing the across-gulf velocities and salinity would show you more about circulation.
What about your wind driven circulation, what do you expect from it??
You are also dealing with a complex geometry that can induce residual tidal circulation, but 60 cm/s is too much.
At last, what the observations tell you about these horizontal shear, is it real?
Good luck
Carlos
You have water entering the gulf in one side and leaving it in the other side. This horizontal shear can induce the eddy.
I have seen it when studding the Spencer Gulf, Australia but it is a much larger gulf. The inverse circulation in Spencer Gulf is in a geostrophic adjustment which results in water entering the gulf in on side and leaving it on the other side. But again, it is a much larger gulf. Have a look in Nunes and Lennon(1987) https://doi.org/10.1029/JC092iC05p05465
When you look at your salinity results can you see relative fresher water in on side compared with the other side?
A vertical section showing the across-gulf velocities and salinity would show you more about circulation.
What about your wind driven circulation, what do you expect from it??
You are also dealing with a complex geometry that can induce residual tidal circulation, but 60 cm/s is too much.
At last, what the observations tell you about these horizontal shear, is it real?
Good luck
Carlos
mmonim wrote: ↑Tue Jun 23, 2020 11:02 am Hi All,
I recently configured ROMS for a hindcast simulation in Persian Gulf for the period of 2016-2019. The tidal input came from OTPS while the hydrodynamic and atmospheric forcing came from HYCOM analysis and GFS respectively. After completing the simulation I averaged the surface current at the Strait of Hormuz (please see the figure attached). As the Persian Gulf has inverse-estuarine circulation I was hoping to see flow coming in from Gulf of Oman (as tide should be neutralized after averaging U and V). However, instead of seeing the inflow at the surface I see eddy like structures on both sides of the strait. Could anyone please comment on why i see this eddies, and what i should do if I want to see/model the inflow at the surface? Does the vertical stretching function in grid making can make an impact here?
kind regards,
Mahmud