Include additional data for gw_model

[penguian]

keyword_maygit owner:jxs599@nci.org.au resolution_fixed type_ACCESS-CM2 | by m.decker@unsw.edu.au

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The version of the gw_model code in Share/vn10.6_CABLE@1072 uses parameters as defined in Decker (2015) (except for aquifer thickness soil%GWdz,documented here). They were meant to be temporary pending the release of new data. The current version uses globally constant parameters for calculating the moisture dependence of subsurface drainage and applies the soil column parameters to the aquifer.

The cable code for these modifications is ^branches/dev/markdecker/stable_vn10.6_CABLE_SSGW@10899 The um code is ^branches/dev/markdecker/r43437_vn10.6_CABLE_SSGW_noSLI@50953

A publication documenting the updated gw model is forthcoming.

Modification #1 Replace the globally constant aquifer layer thickness. The aquifer thickness now varies spatially using the data from Shangguan et al 2017. A user can still use a constant thickness of 20 by altering the rose suite.

Modification #2 Modify q_sub(wtd,slope,gw_params) to utilize basin characteristics. controls how subsurface runoff (rnof2) depends on the water table.

Currently the subsurface drainage rate (q_sub) is found with

ssnow%qhz = gw_params%gw_params%MaxHorzDrainRate * soil%slope * exp(-ssnow%wtd/gw_params%EfoldHorzDrainRate)

The formula is

ssnow%qhz = gw_params%gw_params%MaxHorzDrainRate * soil%slope * exp(-ssnow%wtd/(A*gw_params%EfoldHorzDrainRate*soil%drain_dens+B))

The constants A and B are chosen to be 60.0 and 1.0e-3 to give the same dependence as the old version if globally averaged. soil%drain_dens is the drainage density, the inverse of the mean distance to a river, derived by Schneider et al. (2017). Users can reproduce the old formulation by modifying the rose suite to use a constant value instead of the ancil file.

Modification #3 Use observations to set the aquifer hydraulic conductivity instead of using the soil properties. The conductivity of the aquifer is derived from the permeability data from GLHYMPS (Gleeson et al. 2014). Currently uses do not have a simple way of using the pervious method as a new ancil file must be created.

Each of the above requires reading an additional ancil file, creating a new D1 variable and stash code.

New STASH The stashcodes are: 1| 1 | 0 | 836 |CABLE THCKNESS (m) 1| 1 | 0 | 840 |CABLE AQUIFER PRM (-) 1| 1 | 0 | 841 |CABLE AQUIFER DrD (-)

Additional ancil files /g/data1/w35/mrd561/ACCESS_ancils/v2/GWdz.anc /g/data1/w35/mrd561/ACCESS_ancils/v2/qrparm.permeability.n96.anc /g/data1/w35/mrd561/ACCESS_ancils/v2/qrparm.draindense.n96.anc

The rose suite u-av568, which is updated to read the ancil files.

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Issue migrated from trac:193 at 2023-11-27 11:25:54 +1100

[penguian]

@jxs599@nci.org.au changed status from new to closed

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@jxs599@nci.org.au changed resolution from ` tofixed`

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@jxs599@nci.org.au changed milestone from ` to1. Closed`

[penguian]

@ccc561@nci.org.au set keywords to maygit