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ACCESS-Community-Hub / Land-ancillary-creation

A repository containing scripts to create ancillary files for land surface models for ACCESS
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JULES ancil fields from ANTS that are reusable in CABLE #2

Open tammasloughran opened 2 weeks ago

tammasloughran commented 2 weeks ago

Here I have created a list of variables from ANTS output for JULES that may be used for CABLE ancillary fields.

Description JULES Notes CABLE
Leaf area index leaf_area_index JULES has 5 PFTs while CABLE has 11 LAI
Snow free bare soil albedo soil_albedo (1) albedo2 (1)
Soil heat capacity hcap (J m-3 K-1) needs unit conversion css (J kg-1 K-1)
Soil thermal conductivity hcon (W m-1 K-1) cnsd (W m-1 K-1)
Soil Bulk density BD (kg m-3) rhosoil (kg m-3)
Soil suction at saturation sathh (m) sucs (m)
Soil hydraulic conductivity at saturation satcon (kg m-2 s-1) needs unit conversion hyds (ms)
Critical soil moisture stress sm_crit (m3 m-3) sfc (1)
Wilting point soil moisture sm_wilt (m3 m-3) swilt (1)
Sand fraction T_SAND (m3 m-3) sand (1)
Silt fraction T_SILT (m3 m-3) silt (1)
Clay fraction T_CLAY (m3 m-3) clay (1)
bibivking commented 2 weeks ago

Here is some supplementary information. I’ve placed the Australian 5 km gridinfo file used in CABLE-GW, which I created, in /g/data/rp23/experiments/2024-10-10_LWG_workingbee/mm3972/gridinfo_AWAP_OpenLandMap_ELEV_DLCM_fix.nc. After comparing the JULES input and the CABLE gridinfo, I noticed a few things that CABLE might need from JULES:

1) Landmask: The current landmask in the CABLE gridinfo has missing values due to gaps in the original soil texture map used to calculate soil hydraulic parameters, and it also misses the coastlines. 2) Topography and standard deviation topographic index: These are at a coarse resolution in CABLE. 3) Canopy height: This is prescribed in the CABLE code, but JULES has a canopy height map that might be worth trying. 4) LAI: The LAI values differ between the JULES and CABLE inputs, so we need to check if CABLE requires any updates.

Regarding soil hydraulic parameters, I’m not sure if the JULES input is necessarily better than CABLE’s. First, the maps of soil hydraulic parameters in JULES seem to come from lookup tables based on soil types. However, the hydraulic parameters in CABLE’s gridinfo are calculated using pedotransfer functions and soil textures, so CABLE’s maps might be better. Second, the soil hydraulic parameters used in JULES don’t exactly match those in CABLE, as JULES uses the Van Genuchten water retention equation, while CABLE uses the Campbell equation.

Additionally, I recently became aware that we need to update the parameters for CABLE-GW, such as Sy, dtb, drainage density, and permeability. I took these values from a file left by Mark Decker, but I’m unsure of their data sources.

Lastly, I noticed that the albedo read-in code is somewhat messy, and we have two albedo variables (Albedo and albedo2) in the gridinfo, which could easily confuse model users.