dart_pop_mod
provides a consistent collection of routines that are useful for multiple programs e.g.
dart_to_pop
, pop_to_dart
, etc.
time_manager_nml
namelist and write
an updated version to control the length of the integration of POP. All other information is simply read from the
namelists and is used in the same context as POP itself. The POP documentation should be consulted. Only the
variables of interest to DART are described in this document.pop_in
.namelist /time_manager_nml/ allow_leapyear, stop_count, stop_option
dart_to_pop
controls the model advance of LANL/POP by creating a &time_manager_nml
in pop_in.DART
IFF
the DART state being converted has the 'advance_to_time' record. The pop_in.DART
must be concatenated with the
other namelists needed by POP into a file called pop_in
. We have chosen to store the other namelists (which
contain static information) in a file called pop_in.part2
. Initially, the time_manager_nml
is stored in a
companion file called pop_in.part1
and the two files are concatenated into the expected pop_in
- then, during
the course of an assimilation experiment, DART keeps writing out a new time_manager_nml
with new integration
information - which gets appended with the static information in pop_in.part2
Contents | Type | Description |
---|---|---|
allow_leapyear | logical | DART ignores the setting of this parameter. All observations must use a Gregorian calendar. There are pathological cases, but if you are doing data assimilation, just use the Gregorian calendar. [default: .true.] |
stop_count | integer | the number of model advance steps to take. [default: 1] |
stop_option | character(len=64) | The units for the number of model advance steps (stop_count ) to take.
[default: 'ndays'] |
namelist /io_nml/ luse_pointer_files, pointer_filename
Contents | Type | Description |
---|---|---|
luse_pointer_files | logical | switch to indicate the use of pointer files or not. If .true. , a
pointer file is used to contain the name of the restart file to be used.
DART requires this to be .true . [default: .true.] |
pointer_filename | character(len=100) | The name of the pointer file. All of the DART scripts presume and require the use of the default. Each ensmeble member gets its own pointer file. [default: rpointer.ocn.[1-N].restart] |
namelist /restart_nml/ restart_freq_opt, restart_freq
Contents | Type | Description |
---|---|---|
luse_pointer_files | logical | switch to indicate the use of pointer files or not. If .true. , a
pointer file is used to contain the name of the restart file to be used.
DART requires this to be .true . [default: .true.] |
pointer_filename | character(len=100) | The name of the pointer file. All of the DART scripts presume and require the use of the default. Each ensmeble member gets its own pointer file. [default: rpointer.ocn.[1-N].restart] |
namelist /init_ts_nml/ init_ts_option, init_ts_file, init_ts_file_fmt
The dart_pop_mod:initialize_module()
routine reads pop_in
. There are several code stubs for future use that
may allow for a more fully-supported POP namelist implementation. This namelist is one of them. Until further notice,
the init_ts_nml
is completely ignored by DART.
Contents | Type | Description |
---|---|---|
init_ts_option | character(len=64) | NOT USED by DART. All T,S information comes from a netCDF restart file
named pop.r.nc [default: 'restart'] |
init_ts_file | character(len=100) | NOT USED by DART. All T,S information comes from pop.r.nc [default:
'pop.r'] |
init_ts_file_fmt | character(len=64) | NOT USED by DART. The file format is 'nc' [default: 'nc'] |
namelist /domain_nml/ ew_boundary_type
DART needs to know if the East-West domain is cyclic for spatial interpolations. Presently, DART has only been tested for the dipole grid, which is cyclic E-W and closed N-S.
Contents | Type | Description |
---|---|---|
ew_boundary_type | character(len=64) | switch to indicate whether the East-West domain is cyclic or not. DART/POP
has not been tested in a regional configuration, so DART requires this to
be 'cyclic' . [default: 'cyclic'] |
namelist /grid_nml/ horiz_grid_opt, vert_grid_opt, topography_opt, & horiz_grid_file, vert_grid_file, topography_file
real(r8), dimension(:,:) :: ULAT, &! latitude (radians) of U points real(r8), dimension(:,:) :: ULON, &! longitude (radians) of U points real(r8), dimension(:,:) :: HTN , &! length (cm) of north edge of T box real(r8), dimension(:,:) :: HTE , &! length (cm) of east edge of T box real(r8), dimension(:,:) :: HUS , &! length (cm) of south edge of U box real(r8), dimension(:,:) :: HUW , &! length (cm) of west edge of U box real(r8), dimension(:,:) :: ANGLE &! angle
The vertical grid file is ascii, with 3 columns/line:
cell thickness(in cm) cell center(in m) cell bottom(in m)
Here is what we can get from the topography file:
integer, dimension(:,:), :: KMT &! k index of deepest grid cell on T grid
These must be derived or come from someplace else ...
KMU k index of deepest grid cell on U grid HT real(r8) value of deepest valid T depth (in cm) HU real(r8) value of deepest valid U depth (in cm)
Contents | Type | Description |
---|---|---|
horiz_grid_opt, vert_grid_opt, topography_opt | character(len=64) | switch to indicate whether or not the grids
will come from an external file or not. DART
requires ALL of these to be 'file' .
[default: 'file'] |
horiz_grid_file | character(len=100) | The name of the binary file containing the
values for the horizontal grid. The
dimensions of the grid are read from
pop.r.nc . It would have been nice to
include the actual grid information in the
netCDF files. [default:
'horiz_grid.gx3v5.r8ieee.le'] |
vert_grid_file | character(len=100) | The name of the ASCII file containing the values for the vertical grid. The file must contain three columns of data pertaining to the cell thickness (in cm), the cell center (in meters), and the cell bottom (in meters). Again, it would have been nice to include the vertical grid information in the netCDF files. [default: 'vert_grid.gx3v5'] |
topography_grid_file | character(len=100) | The name of the binary file containing the
values for the topography information. The
dimensions of the grid are read from
pop.r.nc . [default:
'topography.gx3v5.r8ieee.le'] |
types_mod time_manager_mod utilities_mod typesizes netcdf
Only a select number of interfaces used are discussed here. Each module has its own discussion of their routines.
use dart_pop_mod, only : | get_pop_calendar |
set_model_time_step | |
get_horiz_grid_dims | |
get_vert_grid_dim | |
read_horiz_grid | |
read_topography | |
read_vert_grid | |
write_pop_namelist | |
get_pop_restart_filename |
call get_pop_calendar(calstring)
character(len=*), intent(out) :: calstring
Returns a string containing the type of calendar in use.
calstring |
DART/POP uses a 'gregorian' calendar. |
poptimestep = set_model_time_step()
type(time_type), intent(out) :: poptimestep
set_model_time_step
returns the model time step that was set in the restart_nmlrestart_freq
. This is the
minimum amount of time DART thinks the POP model can advance. Indirectly, this specifies the minimum assimilation
interval.
poptimestep |
the minimum assimilation interval |
call get_horiz_grid_dims(Nx, Ny)
integer, intent(out) :: Nx, Ny
get_horiz_grid_dims
reads pop.r.nc
to determine the number of longitudes and latitudes.
Nx |
the length of the 'i' dimension in the POP restart file. The number of longitudes in use. |
Ny |
the length of the 'j' dimension in the POP restart file. The number of latitudes in use. |
call get_vert_grid_dim( Nz )
integer, intent(out) :: Nz
get_vert_grid_dim
reads pop.r.nc
to determine the number of vertical levels in use.
Nz |
the length of the 'k' dimension in the POP restart file. The number of vertical levels in use. |
call read_horiz_grid(nx, ny, ULAT, ULON, TLAT, TLON)
integer, intent(in) :: nx, ny real(r8), dimension(nx,ny), intent(out) :: ULAT, ULON, TLAT, TLON
read_horiz_grid
reads the direct access binary files containing the POP grid information. The first record is
REQUIRED to be 'ULAT', the second record is REQUIRED to be 'ULON'.
nx |
The number of longitudes in the grid. |
ny |
The number of latitudes in the grid. |
ULAT |
The matrix of latitudes for the UVEL and VVEL variables. Units are degrees [-90,90]. |
ULON |
The matrix of longitudes for the UVEL and VVEL variables. Units are degrees. [0,360] |
TLAT |
The matrix of latitudes for the SALT and TEMP variables. Units are degrees [-90,90]. |
TLON |
The matrix of longitudes for the SALT and TEMP variables. Units are degrees. [0,360] |
call read_topography(nx, ny, KMT, KMU)
integer, intent(in) :: nx, ny integer, dimension(nx,ny), intent(out) :: KMT, KMU
read_topography
reads the direct access binary files containing the POP topography information. The first
record is REQUIRED to be 'KMT'. 'KMU' is calculated from 'KMT'.
nx |
The number of longitudes in the grid. |
ny |
The number of latitudes in the grid. |
KMT |
The matrix containing the lowest valid depth index at grid centroids. |
KMU |
The matrix containing the lowest valid depth index at grid corners. |
call read_vert_grid(nz, ZC, ZG)
integer, intent(in) :: nz real(r8), dimension(nz), intent(out) :: ZC, ZG
read_vert_grid
reads the ASCII file containing the information about the vertical levels. The file must contain
three columns of data pertaining to; 1) the cell thickness (in cm),nz |
The number of vertical levels. |
ZC |
The depth (in meters) at the grid centers. |
ZG |
The depth (in meters) at the grid edges. |
call write_pop_namelist(model_time, adv_to_time)
type(time_type), intent(in) :: model_time type(time_type), intent(in) :: adv_to_time
write_pop_namelist
writes the POP namelist time_manager_nml
with the information necessary to advance POP to
the next assimilation time. The namelist is written to a file called pop_in.DART
. Presently, DART is configured
to minimally advance POP for 86400 seconds - i.e. 1 day. The forecast length (the difference between 'model_time' and
'adv_to_time') must be an integer number of days with the current setup. An error will result if it is not.
model_time |
The 'valid' time of the current model state. |
adv_to_time |
The time of the next assimilation. |
call get_pop_restart_filename( filename )
character(len=*), intent(out) :: filename
get_pop_restart_filename
returns the filename containing the POP restart information. At this point the filename
is hardwired to pop.r.nc
, but may become more flexible in future versions. The filename may be derived from
the restart_nml
but is currently ignored.
filename |
The name of the POP restart file. |
filename | purpose |
---|---|
pop_in | to read the POP namelists |
pop.r.nc | provides grid dimensions and 'valid_time' of the model state |
&grid_nml "horiz_grid_file" |
contains the values of the horizontal grid |
&grid_nml "vert_grid_file" |
contains the number and values of the vertical levels |
&grid_nml "topography_grid_file" |
contains the indices of the wet/dry cells |
pop_in.DART | to control the integration of the POP model advance |
- none
N/A