4.3. Driver and Coupling

The driver and coupling layer is found in cicecore/drivers/. The standalone driver is found under cicecore/drivers/cice/ and other high level coupling layers are found in other directories. In general, CICE will build with only one of these drivers, depending how the model is run and coupled. Within the cicecore/drivers/cice/ directory, the following files are found,

CICE.F90 is the top level program file and that calls CICE_Initialize, CICE_Run, and CICE_Finalize methods. CICE_InitMod.F90 contains the CICE_Initialize method and other next level source code. CICE_RunMod.F90 contains the CICE_Run method and other next level source code. CICE_FinalMod.F90 contains the CICE_Finalize method and other next level source code.

Other cicecore/drivers/ directories are similarly implemented with a top level coupling layer, that is largely specified by an external coupled system and then some version of the CICE_InitMod.F90, CICE_RunMod.F90, and CICE_FinalMod.F90 files.

4.3.1. Calling Sequence

The initialize calling sequence looks something like:

call init_communicate     ! initial setup for message passing
call init_fileunits       ! unit numbers
call icepack_configure()  ! initialize icepack
call input_data           ! namelist variables
call init_zbgc            ! vertical biogeochemistry namelist
call init_domain_blocks   ! set up block decomposition
call init_grid1           ! domain distribution
call alloc_*              ! allocate arrays
call init_ice_timers      ! initialize all timers
call init_grid2           ! grid variables
call init_calendar        ! initialize some calendar stuff
call init_hist (dt)       ! initialize output history file
if (kdyn == 2) then
   call init_eap (dt_dyn) ! define eap dynamics parameters, variables
else                      ! for both kdyn = 0 or 1
   call init_evp (dt_dyn) ! define evp dynamics parameters, variables
endif
call init_coupler_flux    ! initialize fluxes exchanged with coupler
call init_thermo_vertical ! initialize vertical thermodynamics
call icepack_init_itd(ncat, hin_max)  ! ice thickness distribution
call calendar(time)       ! determine the initial date
call init_forcing_ocn(dt) ! initialize sss and sst from data
call init_state           ! initialize the ice state
call init_transport       ! initialize horizontal transport
call ice_HaloRestore_init ! restored boundary conditions
call init_restart         ! initialize restart variables
call init_diags           ! initialize diagnostic output points
call init_history_therm   ! initialize thermo history variables
call init_history_dyn     ! initialize dynamic history variables
call init_shortwave    ! initialize radiative transfer
call init_forcing_atmo    ! initialize atmospheric forcing (standalone)

See a CICE_InitMod.F90 file for the latest.

The run sequence within a time loop looks something like:

call init_mass_diags   ! diagnostics per timestep
call init_history_therm
call init_history_bgc

do iblk = 1, nblocks
   if (calc_Tsfc) call prep_radiation (dt, iblk)
   call step_therm1     (dt, iblk) ! vertical thermodynamics
   call biogeochemistry (dt, iblk) ! biogeochemistry
   call step_therm2     (dt, iblk) ! ice thickness distribution thermo
enddo ! iblk

call update_state (dt, daidtt, dvidtt, dagedtt, offset)

do k = 1, ndtd
   call step_dyn_horiz (dt_dyn)
   do iblk = 1, nblocks
      call step_dyn_ridge (dt_dyn, ndtd, iblk)
   enddo
   call update_state (dt_dyn, daidtd, dvidtd, dagedtd, offset)
enddo

do iblk = 1, nblocks
   call step_radiation (dt, iblk)
   call coupling_prep (iblk)
enddo ! iblk

See a CICE_RunMod.F90 file for the latest.