[MITgcm-support] OBCS for deep sewage water source

[cimatori at libero.it]

Hi Martin, some time ago we wrote about this case: we are trying to model the diffusion of a deep 
source of wastewater in a semi-enclosed basin (gulf of Trieste, northern Adriatic) using obcs 
prescribe to attain the effect of lighter water, ptracers (for modeling the polluttant) and exf. We 
use a western obcs at the open side of the gulf (we tried both Orlanski and sponge (nudging) layer) 
and tried to use an eastern boundary for the sewage source. This source is a diffuser offshore on 
the seabed, so we need to prescribe the boundary values only at a particular level (15) leaving the 
rest of the column without any constraint.
This works only if we use a closed domain (without any kind of western open boundary): we see a 
plume of lighter water wich follows the wind-driven currents.
When we open the western boundary we obtain irrealistic velocity fields on the column above the 
diffuser.
We corrected the routines (see attachments) making some improvements but the main problem 
remains.
The problem lies in the use of another open boundary together with the one in the middle of the 
domain (we are going to try using northern or southern obcs instead of eastern for the source: 
maybe it could be a C-grid problem?).
We will check again the source code (expecially our modifications), but, of course, any further 
suggestion is welcome!
Thanks!
Andrea

PS: the passive tracer with obcs seems to give sensible results, at least qualitatively, without 
using the deep source of light water (using only ptracer forcing). See image attached.



____________________________________________________________
Libero ADSL: 3 mesi gratis e navighi a 1.2 Mega, senza costi di attivazione.
Abbonati subito su http://www.libero.it
-------------- next part --------------
A non-text attachment was scrubbed...
Name: U_hor_sect_log(ptrac).png
Type: image/png
Size: 237245 bytes
Desc: not available
URL: <http://mitgcm.org/pipermail/mitgcm-support/attachments/20041213/f7e9258e/attachment.png>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: obcs_apply_uv.F
Type: application/octet-stream
Size: 3224 bytes
Desc: not available
URL: <http://mitgcm.org/pipermail/mitgcm-support/attachments/20041213/f7e9258e/attachment.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: obcs_apply_w.F
Type: application/octet-stream
Size: 2087 bytes
Desc: not available
URL: <http://mitgcm.org/pipermail/mitgcm-support/attachments/20041213/f7e9258e/attachment-0001.obj>