back to CMIP7 ancillaries
Land-use/land-use change forcing for HadCM3
Where to access data
### How to process data
The land-use should be an ancillary file, in the pp format, containing fraction of vegetation (values between 0 and 1) on each point of the land area of the model grid. If the initial land-use file is on a netcdf4 format, convert in on pp format by:
1) Open xancil
2) Load nc file of interest
3) Choose start date, time depth and time step
4) Click on "create ancillary file"
### How to implement the forcing into HadCM3
From umui (access from PUMA2, from archer2)
1) Copy a standard HadCM3B job.
2) To define the path where the ancillary is :
Model Selection -> Sub - Model Independant -> File & Directory Naming
In the table called "Defined Environment Variables for Directories", add in the column "Variable Name" MY_VEG_DIST, and the path corresponding in the other column. For example : $HOME/ancil/ancil_landuse
3) Choose the right ancillaryvfile:
Model Selection -> Atmosphere -> Ancillary and input data files -> Climatologies & potential climatologies -> Vegetation Distribution : Disturbance
In directory or Environment Variable, write path where ancillary is (or let MY_VEG_DIST, if step 2) already completed). Enter file name.
a) If ancillary is static : choose "Disturbed fraction of vegetation to be" : "Configured"
b) If ancillary is a varying land-use : choose "Disturbed fraction of vegetation to be" : "Updated from ancil" and specify the time step corresponding to the land-use update.
4) Especially for varying land-use, do not forget to add these mods:
Model Selection -> Sub - Model Independant -> Compilation and Modifications -> Modifications for the model
In the Fortran mods table, add /user/home/tw23150/mods/gath_fld_co2.mf77 and /user/home/tw23150/mods/disturb_grid_fix.mf77 (Include Y).