Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Possible addition of Brine plume parameterization #116

Open
wants to merge 11 commits into
base: master
Choose a base branch
from

Conversation

vanroekel
Copy link
Collaborator

@vanroekel vanroekel commented Nov 22, 2024

This potential feature is meant to mimic (in a simple way) the parameterization of Nguyen et al 2009 (https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2008JC005121) which is designed to limit the penetration of brine rejection plumes in models that often leads to overly deep haloclines in the arctic. It is my understanding of how Section 3.1 describes the parameterization. Translated to MPAS, I think this should be transporting the seaIceSalinityFlux which is the salinity rejected back to the ocean in ice formation. Here that flux is removed from the KPP non local flux and given a different shape function according to the paper. There is still work to be done, but was hoping for input on the implementation. In particular @maltrud, @milenaveneziani, @alicebarthel and @cbegeman I'd appreciate your thoughts.

thorntonpe and others added 9 commits May 23, 2024 19:16
The stem:leaf allocation variable can go negative without this
limiter, which can cause negative stem carbon pools.
This is necessary for the MALI adaptive timestepper to work without error in
E3SM.
Previously, the total was only being computed when thermodynamics
below ice shelves are actively computed, whereas we need to
compute the total of the interface flux and the frazil flux
when the interface flux comes from a data file as well.  While we
expect the frazil flux to be zero, these code modifications do not
assume or require this to be true.
The stem:leaf allocation variable can go negative without this limiter, which
can cause negative stem carbon pools.

Fixes E3SM-Project#6591
[non-BFB]
…3SM-Project#6725)

Fix alarm error for MALI adaptive timestepper

MALI uses an MPAS alarm to handle ensuring its adaptive timestepper does
not step past a coupling interval. In recent attempts to enable the
adaptive timestepper in MALI within E3SM, it was discovered that the
required alarm is not being reset properly during init in the glc
driver, which results in an error because MALI tries to use a 0 second
dt on the first timestep. This PR resets the alarm in glc_init_mct after
the component clock is finished being set up, which solves the problem.

This PR also enables the adaptive timestepper for the mali-gis20km
testmod to ensure this functionality gets tested. Because the coupling
interval in this test (1 day) is much smaller than the CFL-limiting
timestep, the dt being applied remain unchanged, so there are no answer
changes. But the adaptive timestepper functionality in MALI is active
and being run.

[NML] only for testdef mali-gis20km
[BFB]
Fix total land-ice freshwater flux in data mode

Previously, the total was only being computed when thermodynamics below
ice shelves are actively computed, whereas we need to compute the total
of the interface flux and the frazil flux when the interface flux comes
from a data file as well. While we expect the frazil flux to be zero,
these code modifications do not assume or require this to be true.

Fixes E3SM-Project#6719
[BFB] purely diagnostic
@vanroekel vanroekel added enhancement New feature or request help wanted Extra attention is needed labels Nov 22, 2024
@vanroekel
Copy link
Collaborator Author

My branch is farther along than ocean-discussions master so extra files are in the diffs. Here is a list of files I changed

mpas-ocean/src/Registry.xml
mpas-ocean/src/shared/mpas_ocn_surface_bulk_forcing.F
mpas-ocean/src/shared/mpas_ocn_tendency.F
mpas-ocean/src/shared/mpas_ocn_tracer_nonlocalflux.F

@vanroekel
Copy link
Collaborator Author

I've tested an initial implementation (currently in year 7), here is one plot of averaged MLD (density) in year 5 (JFM average)
image

There is a broad reduction in Arctic MLD.

@cbegeman
Copy link
Collaborator

@vanroekel I tested this in a column case and found that the salinity vertical mixing tendency is much more smooth through the boundary layer (in the presence of negative), which I think is what we want. (I think that there might be a difference in sign convention between the total tendency and the vertical mixing tendency in these figures.)

Brine parameterization off:
image

Brine parameterization on:
image

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
enhancement New feature or request help wanted Extra attention is needed
Projects
None yet
Development

Successfully merging this pull request may close these issues.

7 participants