Water conservation

[MartinDix]

Monthly total water mass and equivalent sea level change from cm3-run-18-09-2024-no-zap-no-iceberg

Even after accounting for snow accumulation (missing iceberg flux) there's a sea level decrease of ~ 3 mm/year.

[MartinDix]

From cm3-run-24-09-2024-fix-wind-stress

The seaice term now includes snow over sea ice
Land water includes soil water and river storage

The river storage increases over the first year, but even with this included the decrease in the first year is larger.

[MartinDix]

River outflow from the UM matches river inflow in MOM so there's no error from the scaling by ocean fraction.

Rate of water loss is ~ 4e7 kg/s which is ~ 2.5% of the total river term.

UM has l_inland=.true. which means that the river flow which ends up in inland basins should be compensated.

[MartinDix]

UM is using ancillaries from /g/data/tm70/mrd599/ancil/n96e_momO1_20201102, created by suite u-cp883. The river sequence file qrparm.rivseq puts ocean outflow points in the Black and Caspian Seas which are 100% land in the 1 degree ocean model. Therefore the river outflow to these points is lost. These points were fixed in the CM2 river sequence file.

In these plots river outflow points are shown in blue, inland basin in brown and blocked outflow points in red. Original on left and fixed on right. Changed points highlighted with thicker arrows.

Outflow to these blocked points was ~ 2.5e7 kg/s, so perhaps not the total solution.

/g/data/tm70/mrd599/ancil/n96e_momO1_20201102/qrparm.rivseq is now the corrected version so any new runs will pick up this change.

[kieranricardo]

@MartinDix nice catch!

The new ancillary seems to generating NaN in the river outflow

[MartinDix]

Something went wrong in handling of masked points in the updated file. Corrected updated version is /g/data/tm70/mrd599/ancil/n96e_momO1_20201102/qrparm.rivseq.20241001. qrparm.rivseq is the original file.