The workflow recommended now is to read in external prior fields in their original format using the grid conversion routines routines provided in the core code.

File format - Gridded prior fields

• Format:
  Input 2D fields are expected as FORTRAN binary files, as written in the following example:
  integer, parameter :: im = ...    ! grid size longitude
  integer, parameter :: jm = ...    ! grid size latitude
  
  integer   :: itau,idate(6)
  real(r4) :: field(im,jm)
  
  open(10,file="...",form="unformatted")
  do
    itau       = ...    ! will be ignored
    idate      = ...    ! date as (/year,month,day,hour,minute,second/)
    field(:,:) = ...    ! values
    write(10) itau,idate,field
  end do
  close(10)
  
• File names:
  Similar to "Datasource.Species.Timestep_Grid.b"
  Example: "EDGAR40.co2.yr_fg.b"
  Standard location: "~/INVERSION/PRIORS/"
• Units:
  Flux files are always expected in units of [Tmol/gridcell/timestep] (= extensive units).
  Positive = source into atmosphere.

Example code is available for converting external data sets into TM3 grid and obeying this format.

In order to check prior files you can convert them to NetCDF by
tm32netCDF_fg Filename 1
(PATH needs to include "/home/zmaw/m212046/TM3/tools/" for tm32netCDF_fg to work).