How to enhance vertical mixing in roms MY2.5

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azamocndu
Posts: 4
Joined: Mon Mar 26, 2018 2:16 pm
Location: Ocean University of China

How to enhance vertical mixing in roms MY2.5

#1 Post by azamocndu » Tue May 28, 2019 3:18 am

Hi
I'm using MY2.5 scheme for mixing.
I have used !AKT_BAK == 1.0d-6 1.0d-6 ! m2/s.
Model output shows subsurface temperature is lower than observation. Surface salinity is also low. My domain is the Bay of Bengal.
I think I should increase mixing. But how to do this in .in file. Which parameters value need to change?

I will be very glad hearing from any kind person.

Thanks

Azam
Email: azam_oceanographer.ocn@du.ac.bd

c.drinkorn
Posts: 82
Joined: Thu Mar 08, 2018 2:47 am
Location: German Research Centre for Geosciences

Re: How to enhance vertical mixing in roms MY2.5

#2 Post by c.drinkorn » Tue May 28, 2019 8:39 am

Hi Azam,

just an idea: Did you try switching between Laplacian and biharmonic horizontal diffusion? I.e., define either TS_DIF2 or TS_DIF4. I don't know whether the issue is too less horizontal or vertical mixing but I guess if your subsurface temperature AND salinity is too low you need more vertical convection? I am not familiar with the Bay of Bengal but if you have a lot of precipitation and river runoff you need more efficient convection in order to obtain a warmer and more saline subsurface. Maybe also try another vertical tracer advection scheme...

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kate
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Location: IMS/UAF, USA

Re: How to enhance vertical mixing in roms MY2.5

#3 Post by kate » Tue May 28, 2019 4:03 pm

I've heard it's a difficult problem. We also have too little vertical mixing from all the fresh water input into the Gulf of Alaska. One idea is that we need to couple to a wave model and enable the wind-wave surface mixing in COAWST. Easier said than done; we haven't tried it yet.

azamocndu
Posts: 4
Joined: Mon Mar 26, 2018 2:16 pm
Location: Ocean University of China

Re: How to enhance vertical mixing in roms MY2.5

#4 Post by azamocndu » Wed May 29, 2019 2:41 am

Hi, c.drinkorn

Thanks for your reply. I didn't try it before. yes Surface T is higher but in 50 to 300 meters depth it is 2-3 degrees low. salinity is less problematic than temperature. Surface salinity is very fresh near river mouth.
Thanks again



Hi Kate

Thanks for your comments

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