Document issues with our mapping file generation tool chain at high resolution. Instructions on using MBtempest: Offline remapping workflow with mbtempest
Status
For PG2 grids, we currently do not have an acceptable solution that would allow us to run at 3km (ne1024). For NP4 grids, Ben Hillman has been using TR mapping files with similar conservation/consistency errors. These are acceptable for development/testing, but not appropriate for coupled simulationswill mapping FV-FV. For monotone conservative linear maps, the only choice is cell integrated using a piecewise constant reconstruction. Options for producing these maps include ESMF, TempestRemap (TR), Moab with TR agorithms (MBTR) and NCO. All codes produce similar max and l2 errors when evaluated with the analytic vortex test field.
As of
NCO: good results, fastest code. ~1.5H using 4 cores (4 threads) Cori-Haswell node. oRRS18to6 → ne1024pg2
TR: good results with code from and with the “--correct_areas” option. Very slow: 15H (1 core) oRRS18to6 → ne1024pg2
MBTR: maps are bad
ESMF: maps for ne1024 are bad.
For NP4 grids,:
TR from : most maps are good, some combinations still produce crashes.
MBTR: maps are bad. is producing bad weights (NaNs or >> 1 ).
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Analysis Mapping files
Mapping files are needed for remapping native grid output to lat/lon grids for conventional analysis tools. Often exact conservation is not required making TR’s integrated bilinear a good option: it’s accurate, has built in downscaling and is monotone so it wont introduce spurious oscillations making it good for plotting.
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ncremap build in FV to FV map file generator
oRRS18to6 → ne256pg2 status: GOOD
~3min with 4 threads on Cori frontend node
Weights are good. row sum and conservation error: 6e-13
oRRS18to6 → ne1024pg2
~40 min on Compy with 4 threads. 1.5 h on Cori-Haswell node
Weights are good. row sum error 2e-12, conservation error 1e-12
TR “mono” . (TR from TR from with new --correct_areas option)
oRRS18to6 → ne256pg2 status: GOOD
2.5h on Anvil (single processor)
Weights are good. Row sums error: 7e-16. Conservation error 7e-16
vortex test field l2/max error: 3.6145e-05 4.3881e-04
oRRS18to6 → ne512pg2: status GOOD
~9h to compute overlap map
weights: good. row sum error: 7e-16. Conservation error 7e-16
vortex: l2, linf: 1.7867e-04 2.2985e-03
oRRS18to6 → ne1024pg2: status: GOOD
15.5h on Anvil, using 20GB
weights: good. row sum error: 4e-16. conservation error: 1e15
MBTR “mono”. Status: NOT USABLE
oRRS18to6 → ne256pg2
Weights are good, but 316 MPAS grid points have weight=0. This is incorrect and corrupts other diagnostics.
ESMF “aave”
oRRS18to6 → ne256pg2. Status: GOOD
weights are good. row sum max 8.5e-12. Conservation error 1.5e-11
vortex test field l2/max error: 3.6144e-05 4.3881e-04
oRRS18to6 → ne512pg2. Status: GOOD
weights are good. row sum error 3e-11. conservation error 1e-11
vortex: l2, linf: 1.7866e-04 2.2985e-03
oRRS18to6 → ne1024pg2. Status: NOT USABLE
35min on Cori Haswell node
( /global/project/projectdirs/acme/taylorm/mapping/map_oRRS18to6v3_to_ne1024pg2_aave.nc.BAD )
weights are bad: max 2.6, row sum max 3.0. conservation error 4e-4
same issue with ESMF v8.
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