What would happen if LMD_BKPP is undefined in LMD scheme?

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jayasankar
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What would happen if LMD_BKPP is undefined in LMD scheme?

#1 Post by jayasankar » Thu Oct 04, 2018 7:26 pm

Hi all,

Could someone tell me what would happen if LMD_BKPP module is undefined while using other modules of LMD scheme?

Also, I would be grateful if you could tell me where can read about all LMD modules.

LMD_SKPP
LMD_BKPP
LMD_RIMIX
LMD_CONVEC
LMD_DDMIX
LMD_NONLOCAL

Thanks in adavance, Jayasankar

jcwarner
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Location: USGS, USA

Re: What would happen if LMD_BKPP is undefined in LMD scheme

#2 Post by jcwarner » Thu Oct 04, 2018 7:52 pm

here is a place to start:
https://www.myroms.org/wiki/Vertical_Mi ... erizations
suggest you also dig into the code a bit. you can grep for those options and they are mostly in Nonlinear/lmd_...

-j

jayasankar
Posts: 15
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Location: India

Re: What would happen if LMD_BKPP is undefined in LMD scheme

#3 Post by jayasankar » Thu Oct 04, 2018 8:26 pm

Hi jc,

Thanks for the reply.I have gone through the link that has been given, however, it doesn't address each module separately nor it mentions a bottom boundary layer. I specifically would like to know what would happen if LMD_BKPP is undefined. Could you help.

Thanks a lot. jay

jcwarner
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Joined: Wed Dec 31, 2003 6:16 pm
Location: USGS, USA

Re: What would happen if LMD_BKPP is undefined in LMD scheme

#4 Post by jcwarner » Thu Oct 04, 2018 8:44 pm

Here is another paper that i remembered-
https://marine.rutgers.edu/po/Papers/Durski_JGR04.pdf
See what Scott did in that paper. I think he undefined the bottom bbl.

The code looks to me like lmd_bkpp computes the eddy diffusivity and viscosity, and will replace those values where
"! Compute boundary layer mixing coefficients, combine them
! with interior mixing coefficients. Take the maximum estimate
! of vertical mixing only where the surface and bottom boundary
! layers overlap. (Do not let the interior overwrite the boundary
! layer estimate)."

So if you dont have bkpp on, then this bottom part would not get computed and the AKV and AKT would extend to the bottom but only based on interior information, not any bottom processes. That is my take on it, but i dont use this mixing scheme.

-john

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kate
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Re: What would happen if LMD_BKPP is undefined in LMD scheme

#5 Post by kate » Thu Oct 04, 2018 8:47 pm

The original KPP has only a surface boundary layer. Scott Durski took the surface BBL and flipped it to add a bottom BBL. Without the bottom one, it is more like pure Large et al.

jayasankar
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Re: What would happen if LMD_BKPP is undefined in LMD scheme

#6 Post by jayasankar » Thu Oct 04, 2018 9:00 pm

Thank you john.
I think the paper would help :D .

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