How to adjust roms temperature with observation (Bias)

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

How to adjust roms temperature with observation (Bias)

#1 Post by azamocndu » Mon Jun 03, 2019 5:09 am

Hi,
My model result is not good enough. Salinity is not a big problem but Temperature(within 50-200 meters’ depth) is the main problem (low:3 to 4 degrees C).
I'm giving details to express my problem in easier way. Sorry for your time.

I'm using MY2.5 scheme,
! Vertical mixing coefficients for tracers in nonlinear model and
! basic state scale factor in adjoint-based algorithms: [1:NAT+NPT,Ngrids]
AKT_BAK == 1.0d-6 1.0d-6 ! m2/s
ad_AKT_fac == 1.0d0 1.0d0 ! nondimensional
! Vertical mixing coefficient for momentum for nonlinear model and
! basic state scale factor in adjoint-based algorithms: [Ngrids].
AKV_BAK == 1.0d-5 ! m2/s
ad_AKV_fac == 1.0d0 ! nondimensional
! Turbulent closure parameters.
AKK_BAK == 5.0d-6 ! m2/s
AKP_BAK == 5.0d-6 ! m2/s
TKENU2 == 0.0d0 ! m2/s
TKENU4 == 0.0d0 ! m4/s

! Harmonic/biharmonic horizontal diffusion of tracer for nonlinear model
! and adjoint-based algorithms: [1:NAT+NPT,Ngrids].

TNU2 == 0.0d0 0.0d0 ! m2/s
TNU4 == 2*0.0d0 ! m4/s
ad_TNU2 == 0.0d0 0.0d0 ! m2/s
ad_TNU4 == 0.0d0 0.0d0 ! m4/s

! Harmonic/biharmonic, horizontal viscosity coefficient for nonlinear model
! and adjoint-based algorithms: [Ngrids]..

VISC2 == 5.0d0 ! m2/s
VISC4 == 0.0d0 ! m4/s
ad_VISC2 == 0.0d0 ! m2/s
ad_VISC4 == 0.0d0 ! m4/s

 Basin averaged temperature (T) of model is 0.5ºC lower (vertically mean) and hence it is lower in all depth than SODA data. Suddenly T is 2-3ºC lower in model within the depth of 55-98m. But the T difference gradually reduces with the increase of the depth after 200m. (higher mixing might solve the problem?)
## I have attached some of output figure and description for details. kindly see.
## I have increased AKT_BAK and also Turbulence closure par (AKK_BAK AND AKP_BAK) by two decimal from the stated above to see if it increase mixing. Yes, model 2nd year result shows huge increase of mixing. But it doesn't increase 50-200 meters depths temperature that much. surface T is reduced a lot. How to reduce the Bias of the upper 200m? my focus on upper layer study.

I'm hanging with this problem for long time.
I will be very glad somebody help me out.

Thanks

Azam
Attachments
compare model with SODA data.docx
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kate
Posts: 3700
Joined: Wed Jul 02, 2003 5:29 pm
Location: IMS/UAF, USA

Re: How to adjust roms temperature with observation (Bias)

#2 Post by kate » Mon Jun 03, 2019 10:41 pm

You've told us about your vertical and horizontal diffusion, but what is the vertical boundary condition? In other words, the surface heat flux? Can you output it and look at it? Is it computed internally (bulk fluxes) or provided externally?

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

Re: How to adjust roms temperature with observation (Bias)

#3 Post by azamocndu » Tue Jun 04, 2019 3:22 am

kate wrote:You've told us about your vertical and horizontal diffusion, but what is the vertical boundary condition? In other words, the surface heat flux? Can you output it and look at it? Is it computed internally (bulk fluxes) or provided externally?
Hi Kate

Yes, I have used COADS climatology atmospheric forcing.
My .h file:
/* atomosphere forcing: */
#define QCORRECTION
#define SCORRECTION

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