Add ISOLATE_MASS_WEIGHT_PGF option to PGF calculation#811
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claireyung wants to merge 2 commits intoNOAA-GFDL:dev/gfdlfrom
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Add ISOLATE_MASS_WEIGHT_PGF option to PGF calculation#811claireyung wants to merge 2 commits intoNOAA-GFDL:dev/gfdlfrom
claireyung wants to merge 2 commits intoNOAA-GFDL:dev/gfdlfrom
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This commit adds the runtime parameter ISOLATE_MASS_WEIGHT_PGF with default value False. If true, then the PGF calculation is modified so that MASS_WEIGHT_IN_PRESSURE_GRADIENT cannot affect cells above and below through the summation of intx_dpa or intx_dza (and y equivalents). This summation can cause problems near the grounding line of ice shelves, even with RESET_INTXPA_INTEGRAL (which was a workaround for this problem), if there is no suitable grid cell in the entire column that is non-vanished and non-tilted. This code recalculates intx_dpa without MASS_WEIGHT_IN_PRESSURE_GRADIENT and uses that non-weighted version for the calculation of intx_pa in subsequent cells,but still retains intx_dpa potentially affected by MASS_WEIGHT_IN_PRESSURE_GRADIENT in the PFu and PFv calculation to retain its desired effect near vanished, sloped layers susceptible to grid-scale noise. Currently the code is very inefficient. As of now, if ISOLATE_MASS_WEIGHT_PGF = True, and MWIPG = True, it calculates the density integrals twice (one with and one without MWIPG). This involves lots of eqn of state calls so slows the model down a lot. This should be improved (though I don’t have a better idea right now). Default answers should not change since default is False, keeping original intx_dpa and allowing MWIPG in one cell to affect cells above/below.
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This commit adds the runtime parameter
ISOLATE_MASS_WEIGHT_PGFwithdefault value False. If true, then the PGF calculation is modified
so that
MASS_WEIGHT_IN_PRESSURE_GRADIENTcannot affect cells above andbelow through the summation of intx_dpa or intx_dza (and y equivalents).
This summation can cause problems near the grounding line of ice shelves,
even with
RESET_INTXPA_INTEGRAL(which was a workaround for this problem),if there is no suitable grid cell in the entire column that is
non-vanished and non-tilted. This code recalculates intx_dpa without
MASS_WEIGHT_IN_PRESSURE_GRADIENTand uses that non-weighted version forthe calculation of intx_pa in subsequent cells,but still
retains intx_dpa potentially affected by
MASS_WEIGHT_IN_PRESSURE_GRADIENTin the PFu and PFv calculation to retain its desired effect near vanished,
sloped layers susceptible to grid-scale noise.
The result is that in the ISOMIP+ test case, combined with #810
velocities near the grounding line are reduced to 10^(-12)m/s.
Currently the code is very inefficient. As of now, if
ISOLATE_MASS_WEIGHT_PGF= True, and MWIPG = True, it calculates ALL the density integrals twice (one with
and one without MWIPG). This involves lots of eqn of state calls so slows the
model down a lot. This should be improved (though I don’t have a better
idea right now).
Default answers should not change since default is False, keeping original
intx_dpa and allowing MWIPG in one cell to affect cells above/below.
I would appreciate suggestions to optimise this code!!