Calculate ww3_bounc geographic distances with haversines and utilize verbose=2 output

[dahonegger]

Pull Request Summary

Bug fix for #1344

Description

When assigning NetCDF spectra to input boundary nodes, ww3_bounc uses an iterative method to identify the two nearest neighbor spectra in spec.list. Custom diagnostic output in ww3_bounc reveals that points even one kilometer apart can be calculated as having a separation distance of zero. Moreover, some input point - boundary point pairs result in a returned distance of NaN. As a result, assignment of spectra to boundary nodes is sensitive to the ordering of the boundary nodes and to the ordering of the provided spectra in a manner that is not explicit in the code.

This fix replaces usage of DIST_SPHERE in ww3_bounc with a new function, DIST_HAVERSINE, that is more robust when distances are on the order of 1 km or less. Both DIST_SPHERE and DIST_HAVERSINE are defined in w3servmd.

This fix additionally includes the option for more detailed diagnostic output from ww3_bounc that is triggered with the VERBOSE=2 namelist value in ww3_bounc.nml.

There are expected changes to regression tests tp2.8 and tp2.17 owing to modifications to the weight assignments of the linearly interpolated boundary spectra.

Issue(s) addressed

• Fixes #1344

Commit Message

Calculate ww3_bounc geographic distances with haversines and utilize verbose=2 output

Check list

• Branch is up to date with the authoritative repository (NOAA-EMC) develop branch.
• Checked the checklist for a developer submitting to develop.
• If a version number update is required, checked the updating version number checklist.
• If a new feature was added, a regression test for testing the new feature is added.

Testing

mww3_test_03/./work_PR3_UNO_MPI_d2_c                     (4 files differ)
mww3_test_03/./work_PR3_UNO_MPI_e_c                     (1 files differ)
mww3_test_03/./work_PR2_UQ_MPI_e                     (1 files differ)
mww3_test_03/./work_PR3_UNO_MPI_d2                     (3 files differ)
mww3_test_03/./work_PR2_UNO_MPI_d2                     (6 files differ)
mww3_test_03/./work_PR3_UQ_MPI_d2                     (9 files differ)
mww3_test_03/./work_PR2_UQ_MPI_d2                     (6 files differ)
mww3_test_03/./work_PR3_UQ_MPI_d2_c                     (8 files differ)
mww3_test_03/./work_PR1_MPI_e                     (1 files differ)
mww3_test_03/./work_PR1_MPI_d2                     (5 files differ)
mww3_test_03/./work_PR3_UQ_MPI_e                     (1 files differ)
mww3_test_09/./work_MPI_ASCII                     (0 files differ)
ww3_tp2.17/./work_ma                     (1 files differ)
ww3_tp2.17/./work_mc1                     (1 files differ)
ww3_tp2.17/./work_mb                     (1 files differ)
ww3_tp2.17/./work_mc                     (1 files differ)
ww3_tp2.17/./work_ma1                     (1 files differ)
ww3_tp2.17/./work_a                     (1 files differ)
ww3_tp2.17/./work_c                     (1 files differ)
ww3_tp2.17/./work_b                     (1 files differ)
ww3_tp2.6/./work_ST4_ASCII                     (0 files differ)
ww3_tp2.8/./work_PR3_UQ                     (4 files differ)

• How were these changes tested? Via matrix
• Are the changes covered by regression tests? (If not, why? Do new tests need to be added?) Tests that use ww3_bounc with FLAGLL=.true. cover the changes, but the newly utilized VERBOSE=2 value in ww3_bounc.nml is not tested.
• Have the matrix regression tests been run (if yes, please note HPC and compiler)? Yes, on an ERDC HPC with Intel
• Please indicate the expected changes in the regression test output, (Note the list of known non-identical tests.) Expected changes to the regression tests include: modifications to the weight assignments of the linearly interpolated boundary spectra.
• Please provide the summary output of matrix.comp (matrix.Diff.txt, matrixCompFull.txt and matrixCompSummary.txt):

matrixCompSummary.txt
matrixDiff.txt
matrixCompFull.txt

[MatthewMasarik-NOAA]

Thank you for submitting this fix @dahonegger. We will start looking at it and I'll reply back tomorrow with the CM assigned and the timeline.

[mickaelaccensi]

Thank you David for this improvement !

[MatthewMasarik-NOAA]

@dahonegger I spoke with @JessicaMeixner-NOAA offline and we will be assigning a CM on Monday when @sbanihash is back from leave. We will be back in touch then. Thank you again for this submission.

[sbanihash]

Thank you @dahonegger for your work on this fix. I would like to request @kestonsmith-noaa to take a look at this PR and review the changes. Either @JessicaMeixner-NOAA or I would also take a look as a second reviewer as well.