TERREAD – Orography

The following options are for the terread namelist, used to create orography and land-sea mask data for the specified cubic grid.  The orography file is used to specify the cubic grid for all other CCAM software.  Further details on defining a cubic grid can be obtained from the following link Conformal Cubic Grid.

Terread is run from the command line

terread < top.nml

where top.nml defines the terread namelist that is described below.

&topnml

il – Size of the cubic grid.  For example, il=96 refers to 96 x 96 x 6 horizontal grid points, or 96 x 96 grid points for each of the six cubic panels.

rlong0 – Longitude corresponding to the centre of the variable resolution cubic grid.

rlat0 – Latitude corresponding to the centre of the variable resolution cubic grid.

schmidt – Schmidt factor that controls the amount of grid stretching ( 0 > schmidt >= 1).  A value of schmidt=1 indicates no stretching or a (quasi-) uniform global grid.  The lower the value of Schmidt, then the greater the amount of stretching.  Simulations without atmospheric nudging are not recommended to use schmidt<0.3.  Also grids with schmidt<0.005 can require modifications to the atmospheric nudging.  Note that the mathematical Schmidt factor is >=1, so this parameter is the inverse of the mathematical definition.

fileout – Output filename for the orography data on the cubic grid, to be used by CCAM

do1km – Set to ‘true’ to include 1 km DEM data in the output orography file

do250 – Set to ‘true’ to include 250m orography data for Australia in the output orography file

dosrtm – Set to ‘true’ to include 50m STRM data in the output orography file.  This requires the user to download at least some of the STRM data.

netout – Set to ‘true’ to use NetCDF formatted output files (recommended).

topfilt – Set to ‘true’ to impose a 2*dx filter to smooth orography (recommended).

filepath10km – Location of 10 km input orography data (i.e., topo2)

filepath1km – Location of 1 km input orography data (i.e., location of *.DEM files)

filepath250m – Location of 250 m input orography data (i.e., location of *.ter files)

filepathstrm – Location of 50 m input orography data (i.e., location of *.hgt files)

do250lsm – set to ‘true’ if wanting to use modis/srtm 250 m land sea mask data for high resolution region (Note: with this, possibly set siblsm=f in sibveg)

filepath250mlsm – directory which contains the 250m grid land-sea mask panel data (data can be downloaded from https://hpc.csiro.au/users/72365/lsmdata/)