Nemo merge requestshttps://forge.nemo-ocean.eu/nemo/nemo/-/merge_requests2024-02-02T11:18:30Zhttps://forge.nemo-ocean.eu/nemo/nemo/-/merge_requests/133Coarsening of the BGC model via OASIS2024-02-02T11:18:30ZEric MaisonnaveCoarsening of the BGC model via OASISTwo configurations must be modified:
1- NEMO ocean-ice only. Add a new coupling interface to provide ocean variables to BGC and receive light absorption coefficient.
2- OFFLINE including the TOP-PISCES model. Add the coupling interface c...Two configurations must be modified:
1- NEMO ocean-ice only. Add a new coupling interface to provide ocean variables to BGC and receive light absorption coefficient.
2- OFFLINE including the TOP-PISCES model. Add the coupling interface counterpart and modify the grid definition.
Two new tools must be added:
1- DOMAINcfg (as already done in dev_agrif_coarsening branch) that deduces the coarsened grid from the ocean grid.
2- a new tool that builds OASIS coarsening weights based on both fine and coarsened grids
A set of new Input files necessary to run the two models together (BGC input files on the coarsened grid, OASIS parameter file, namelists, XIOS XLM files)
Closes #852023 WPEric MaisonnaveEric Maisonnavehttps://forge.nemo-ocean.eu/nemo/nemo/-/merge_requests/332Draft: Resolve "TOP light scaling under seaice create anomalous blooms"2023-08-18T12:28:50Zjulien PalmieriDraft: Resolve "TOP light scaling under seaice create anomalous blooms"Closes #261
Testing the light-Chl coupling in MEDUSA alongside the other light attenuation scheme, It appears that the biology is doing abnormally well under sea-ice in the Arctic, except in time of perpetual night (i.e: November to mi...Closes #261
Testing the light-Chl coupling in MEDUSA alongside the other light attenuation scheme, It appears that the biology is doing abnormally well under sea-ice in the Arctic, except in time of perpetual night (i.e: November to mid-January). As soon as `QSR` is slightly rising, the phytoplankton blooms.
It seems this come from the light module `trcopt`, where the sea-ice impact on light is done this way :
```fortran
! Photosynthetically Available Radiation (PAR)
! --------------------------------------------
DO_2D( 0, 0, 0, 0 )
zqsr_corr(ji,jj) = parsw(ji,jj) * qsr(ji,jj) / ( 1.-fr_i(ji,jj) + rtrn )
END_2D
!
CALL trc_opt_par( kt, zqsr_corr, ze1, ze2, ze3 )
!
```
The same mistake is done in PISCES' `p4zopt`
A simple solution would be to multiply instead of dividing by the ice fraction :
```fortran
DO_2D( 0, 0, 0, 0 )
zqsr_corr(ji,jj) = parsw(ji,jj) * qsr(ji,jj) * ( 1.-fr_i(ji,jj) + rtrn )
END_2D
```
see here a one year Hovmoller of the PAR. First plot using MEDUSA usual light scheme, and bellow using `trcopt`. NEMO-MEDUSA is running 1D here, in a location between Svalbard and Greenland. The x axis is the time of year in year (0.5 is june).\
![image](/uploads/cccc505e72b9ae2de4fa10e31489a34f/image.png)
![image](/uploads/240116edbeb6ab3b302fa7e9f28aaeff/image.png)
here the impact on Chl : \
![image](/uploads/c808bd233d9599e739036923447d3afb/image.png)
![image](/uploads/13f30f989ada6b11cfac4d43dd7599d2/image.png)
As we can see, there's definitely a problem there.julien Palmierijulien Palmierihttps://forge.nemo-ocean.eu/nemo/nemo/-/merge_requests/481Draft: Resolve "Tracers in Sea Ice"2024-03-13T14:15:00ZRenaud PersonDraft: Resolve "Tracers in Sea Ice"Closes #394Closes #394Renaud PersonMartin Vancoppenollemartin.vancoppenolle@locean.ipsl.frRenaud Person