Mixing Layer Temperature calculation in the ocean model

[Lixiang]

Hi All,

I am running WRF with the Mixing layer ocean model. I find that the ocean mixing layer temperature is calculated as (in phys/module_sf_oml.F/OML1D):

if(tml.ge.tmoml .and. h.ne.0.)then if(tml.ge.tmoml)then tml=max(t0ml - Gam*(h-h0) + 0.5*Gam*h + A2/h, tmoml) else tml=tmoml endif u=hu2/h v=hv2/h else tml=t0ml u=0. v=0. endif

I have a qestion about the tml:
As I understand, tmoml is the top 200 m ocean mean temperature (K) at initial time, which equals to TSK(initial skin temperature as I understand)-5 (in phys/module_sf_oml.F/omlinit). So the tml is not allowed to decrease more than 5K. I was wondering why we need to limit the change whithin 5K?

I am new to the ocean model, so any hints would be very much appreciated! Thanks!

 

[Ming Chen]

Please read the paper and hope it is helpful for you to find the information:
Chia-Ying Lee and Shuyi S. Chen, 2012: Symmetric and asymmetric structures of hurricane boundary layer in coupled atmosphere–wave–ocean models and observations. J. Atmos. Sci., 69, 3576–3594. doi: Symmetric and Asymmetric Structures of Hurricane Boundary Layer in Coupled Atmosphere–Wave–Ocean Models and Observations

 

[Lixiang]

Please read the paper and hope it is helpful for you to find the information:
Chia-Ying Lee and Shuyi S. Chen, 2012: Symmetric and asymmetric structures of hurricane boundary layer in coupled atmosphere–wave–ocean models and observations. J. Atmos. Sci., 69, 3576–3594. doi: Symmetric and Asymmetric Structures of Hurricane Boundary Layer in Coupled Atmosphere–Wave–Ocean Models and Observations

Thanks for the reply!

I have already checked the paper, but I am still confused. If I use WRF to simulate some seasonal variations, which can have an SST change as large as 10 K, wouldn't this tml limit make the simulation impossible?

Sorry if I asked some stupid questions. Thank you for your patience.

 

[Ming Chen]

I believe that the 3D ocean model is not a good option for seasonal simulation. This is because the ocean model is not a truly ocean model that describes the full physics/dynamics in the ocean. It more or less still behaves like a 'slab' ocean scheme.
for seasonal simulation using WRF, I would recommend turning off ocean scheme and turning on sst_update.