Alternative remapping s/r #251
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- New function remap_via_sub_cells() returns to the idea of remapping by projection implemented via sub-cell integrals with a correction step to the sub-cell integrals that ensures accurate conservation. - Also added a function for evaluating the average of a single cell's reconstruction over an interval within the cell.
- remap_by_via_sub_cells() is now remap_via_sub_cells()
- On exiting the cycling over sub-cells, the remap_via_sub_cells() routine did not have an target association for the very last sub-cell.
- Separated integral calculations into their own loop - will later help create a vectorized version of remapping. - Expressed non-dimensional positions in terms of effective thickness so that positions are always bounded by source cell. - Removed unused argument, dh, to average_value_ppoly().
- remappingUnitTests now tests remap_via_sub_cells()
Hallberg-NOAA
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Dec 4, 2022
There are extra US%T_to_s scaling factors in the expressions for ustar_min that were recently introduced with dev/gfdl PR mom-ocean#251; these are duplicative of the scaling factor that is already being applied when the parameter OMEGA is read in. The resulting expressions for ustar_min therefore effectively have units of [Z s T-2 ~> m s-1] when they should have units of [Z T-1 ~> m s-1]. Because ustar_min is a tiny floor on the magnitude of ustar, there is a range of values of T_RESCALE_POWER that will give the same answers as when it is 0, but for large enough values the answers will change, perhaps dramatically. This small commit removes these extra factors. Answers will change for some large values of T_RESCALE_POWER, but they are bitwise identical in the TC testing and in MOM6-examples based regression tests with modest or negative values.
Hallberg-NOAA
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Dec 16, 2022
There are extra US%T_to_s scaling factors in the expressions for ustar_min that were recently introduced with dev/gfdl PR mom-ocean#251; these are duplicative of the scaling factor that is already being applied when the parameter OMEGA is read in. The resulting expressions for ustar_min therefore effectively have units of [Z s T-2 ~> m s-1] when they should have units of [Z T-1 ~> m s-1]. Because ustar_min is a tiny floor on the magnitude of ustar, there is a range of values of T_RESCALE_POWER that will give the same answers as when it is 0, but for large enough values the answers will change, perhaps dramatically. This small commit removes these extra factors. Answers will change for some large values of T_RESCALE_POWER, but they are bitwise identical in the TC testing and in MOM6-examples based regression tests with modest or negative values.
marshallward
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Dec 18, 2022
There are extra US%T_to_s scaling factors in the expressions for ustar_min that were recently introduced with dev/gfdl PR mom-ocean#251; these are duplicative of the scaling factor that is already being applied when the parameter OMEGA is read in. The resulting expressions for ustar_min therefore effectively have units of [Z s T-2 ~> m s-1] when they should have units of [Z T-1 ~> m s-1]. Because ustar_min is a tiny floor on the magnitude of ustar, there is a range of values of T_RESCALE_POWER that will give the same answers as when it is 0, but for large enough values the answers will change, perhaps dramatically. This small commit removes these extra factors. Answers will change for some large values of T_RESCALE_POWER, but they are bitwise identical in the TC testing and in MOM6-examples based regression tests with modest or negative values.
gustavo-marques
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Aug 30, 2023
* Add Leith+E
This commit adds the 2D Leith+E closure, which uses a modified 2D Leith biharmonic viscosity paired with a harmonic backscatter. ('Modified' here is not used in the same sense as 'modified 2D Leith'; it just means that the biharmonic coefficient is modified to account for enstrophy backscatter.) Variables are often named 'leithy' to refer to Leith+E.
The parameterization is controlled by three main entries in user_nl_mom:
1. USE_LEITHY = True
2. LEITH_CK = 1.0
3. LEITH_BI_CONST = 8.0
To use Leith+E you should have LAPLACIAN=True and BIHARMONIC=True. (It doesn't hurt to be explicit and also set LEITH_AH=False, along with any other viscous closures, but this is not required. If USE_LEITHY=True it will not use any of the other schemes. It does use the background value of the biharmonic coefficient as a minimum, but ignores the
background harmonic value.) LEITH_CK is the fraction of energy dissipated by the biharmonic term that gets backscattered by the harmonic term (it's a target; the backscatter rate is not exact.) Recommended values between 0 and 1. LEITH_BI_CONST is Upsilon^6 where Upsilon is the ratio between the grid scale and the dissipation scale for enstrophy.
Values should be greater than or equal to 1; 8 is a good place to start.
The code is sensitive to the background value of Ah; specifically, if Ah is too large, the code is unstable. This is because the backscatter coefficient is proportional to Ah, and if Ah is large then you get large backscatter. If your code is unstable, consider reducing, e.g., `AH_VEL_SCALE`.
* Background Ah
This commit updates the code so that it uses the background Ah as
a minimum. Previously, if `SMAGORINSKY_AH = True`, Leith+E would
use the Smag value of Ah as the minimum, which is incorrect.
* Improve logging
Removed `do_not_log` condition on `USE_LEITHY`
* Fix Leithy Logic
Added one line to fix the fact that the code would only work as
intended if either (i) writing out Ah_h, or (ii) in debug mode.
Also swapped .le. and .lt. for <= and <.
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Draft of low-level remapping written to unequivocally avoid overshoots and retain accurate conservation in presence of numerical round-off.
Todo: