no advection of biological variables in NPZD-Powell.

[sksdhdbfl]

Hi.
I'm Yuri Oh in South Korea.

I have been conducting a 3 dimensional biological-physical coupled model using the NPZD-Powell model for a last 1 year. ROMS version is 624.
My Question is how I make an advection of biological variables (Nutient,Phyto,Zoo,Detritus) is not working??
I try to investigate the effect of nutrient supplys on ecosystem dividing into two: horizontal supply and vertical supply.
I think no advection of biological variables means vertical supply of biological biomass only.

I defind horizontal advection scheme as TS_U3HADVECTION
and I find it out an advection stuff is calculated in step3d_t.F90 and pre_step3d.F90.

I edited only step3d_t.F90 for no advection as below (pre_step3d.F90 was not edited).
But model blew up with huge negative biological values. physical values were fine.

How can I make no advection for biological variables is working correctly??
Thanks


<edited step3d_t.F90 as below>
!-----------------------------------------------------------------------
! Time-step horizontal advection term.
!-----------------------------------------------------------------------
T_LOOP : DO itrc=1,NT(ng)
K_LOOP : DO k=1,N(ng)
.....
! Time-step horizontal advection term. Advective fluxes have units
! of Tunits m3/s. The new tracer has units of m Tunits.
DO j=Jstr,Jend
DO i=Istr,Iend
cff=dt(ng)*pm(i,j)*pn(i,j)
cff1=cff*(FX(i+1,j)-FX(i,j))
cff2=cff*(FE(i,j+1)-FE(i,j))
cff3=cff1+cff2
if (itrc .gt. 2) then
t(i,j,k,nnew,itrc)=t(i,j,k,nnew,itrc)
else
t(i,j,k,nnew,itrc)=t(i,j,k,nnew,itrc)-cff3
endif
END DO
END DO
END DO K_LOOP
END DO T_LOOP

[kate]

I suggest you print out values of T,S as well as bio tracers at every step through pre_step3d.F and step3d_t.F. You will see that time slice 3 is not say temperature but rather temperature times Hz. You might find that you also need to edit pre_step3d.F.

[arango]

If you want to remove the horizontal advection of tracer, you may set-up a double periodic application in a 5x5xN grid. This converts ROMS into one-dimensional model where you can study all the vertical biological processes. We actually do this in the BIO_TOY test case for the available ecosystem models. There is not physics in these 1D applications.