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 will 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.
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TR “intbilin”
several issues with loss of precision documented on HOMME-NH dycore scaling to 1km /wiki/spaces/NGDNA/pages/831554328
SE GLL to SE GLL
These mapping files are mostly used to generate initial conditions. Remapping the cam.i file from a spunup NE30 simulation will generate a reasonably well spunup initial condition file for higher resolutions.
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The TR improvements suggest we should take another look at “mono” maps for MPAS/EAM coupling. For these maps, testing reported on Transition to TempestRemap for Atmosphere grids recommended using the transpose of the np4->MPAS mono map. So we test the original map here:
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MBTR FV->FV error - missing source points. It appears MBTR maps have a similar loss of precision as TR maps, but this could be corrupted du to the missing source points.
MBTR SE->SE: montone weights are bad, either NaN or >1
ESMF “aave” and “bilin” maps are good up to ne512pg2, but both produce too large weights with ne1024pg2 (both SE->SE and FV->SE)
AnalyzeMap (Added in TR as of )
request: add min/max of map file frac_a, frac_b data to output
request: check for NaNs when printing weight min/max
for non global (MPAS) source grid, prints tens of thousands of useless consistency warnings
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weights: verify that all weights are between [0,1], none of them are NaNs.
row sums: The row sum consistency check measures the ability of the map to preserve the constant function.
ocean->atm maps: max value should be close to 1.0. min value will be between [0..1] at land and fractional land points. Error reported above is from the max value.
atm->ocean maps: min/max value should be close to 1.0 for all rows with nonzero weights (since atmosphere grid is global)
atm->atm maps: min/max values should be close to 1.0
area weighted column sums: this measures if the map is conservative.
ocean->atm maps: area_b weighted column sum should equal area_a for all columns.
atm->ocean maps: area_b weighted column sum should equal area_a at all ocean points, and be between [0,1] at fractional (coastline) points.
atm->atm maps: equal for all columns.
Older versions of ncremap option is missing global attributes needed by CIME’s domain generation code. they can be added via:
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