+Add BACKSCATTER_UNDERBOUND#656
Merged
marshallward merged 2 commits intoJun 18, 2024
Merged
Conversation
Added the new runtime parameter BACKSCATTER_UNDERBOUND that can be set to false to avoid a potential source of numerical instabilities from excessively large biharmonic viscosities due to overly generous bounds where there are negative Laplacian viscosities due to backscatter parameterizations. Setting this to true reproduces the previous solutions, while setting it to false treats negative and zero Laplacian viscosities the same way when bounding the biharmonic viscosity. When the Laplacian viscosities are all non-negative, the value of BACKSCATTER_UNDERBOUND makes no difference. The default is true for historical reasons, but this option probably should be set to false to avoid certain numerical instabilities from the horizontal viscosities. By default, all answers are bitwise identical, but there are new entries in MOM_parameter_doc files for cases that set both BETTER_BOUND_KH and BETTER_BOUND_AH to true.
Hallberg-NOAA
added
enhancement
adcroft
approved these changes
Jun 13, 2024
Member
|
Gaea regression: https://gitlab.gfdl.noaa.gov/ogrp/mom6ci/MOM6/-/pipelines/23877 ✔️ 🟡 |
This was referenced Nov 27, 2024
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Added the new runtime parameter
BACKSCATTER_UNDERBOUNDthat can be set to false to avoid a potential source of numerical instabilities from excessively large biharmonic viscosities due to overly generous bounds where there are negative Laplacian viscosities due to backscatter parameterizations. Setting this to true reproduces the previous solutions, while setting it to false treats negative and zero Laplacian viscosities the same way when bounding the biharmonic viscosity. When the Laplacian viscosities are all non-negative, the value ofBACKSCATTER_UNDERBOUNDmakes no difference. The default is true for historical reasons, but this option probably should be set to false to avoid certain numerical instabilities from the horizontal viscosities. By default, all answers are bitwise identical, but there are new entries in MOM_parameter_doc files for cases that set bothBETTER_BOUND_KHandBETTER_BOUND_AHto true.