4.3 Specification of history and restart files

The following describes namelist variables associated with history, restart, and initialization files. In what follows, max_tapes denotes the maximum allowable number of different types of history files (tapes) that the model can produce (currently set to 6) and max_flds denotes the maximum number of history fields that may appear on any given history tape (currently set to 1000).

name

HIST_CRTINIC

description

Frequency with which initial datasets will be generated.
Valid values are 'MONTHLY','YEARLY' or'NONE'.

type

char*8

mode

offline, ccsm (obtained from atm in cam mode)

default

'YEARLY'

name

HIST_NHTFRQ(max_tapes)

description

History tape interval(s) (+ for model time steps, - for hours, 0 for monthly ave) (see ex. 4).

type

integer array (1:max_tapes)

mode

offline, ccsm (obtained from atm in cam mode)

default

-24

name

HIST_MFILT(max_tapes)

description

Number of time samples per history tape(s) (see ex. 4).

type

integer

mode

offline, ccsm (obtained from atm in cam mode)

default

1

name

HIST_NDENS(max_tapes)

description

Output tape precision(s). Valid values are 1 (double precision) or 2 (single precision).

type

integer

mode

all

default

2

name

HIST_DOV2XY(max_tapes)

description

Per tape spatial averaging flag. If set to true, produces grid-average history fields on output tape. If set to false, one-dimensional fields are produced (see ex. 4).

type

logical

mode

all

default

.TRUE.

name

HIST_AVGFLAG_PERTAPE(max_tapes)

description

Per tape time averaging flag. Valid values are 'A' (average over history period), 'I' (instantaneous), 'X' (maximum over history period) or 'M' (minimum over history period).

type

char*1

mode

all

default

blank

name

HIST_TYPE1D_PERTAPE(max_tapes)

description

Per tape one dimensional output type. Only used if one dimensional output is selected for the given tape (via the setting of HIST_DOV2XY). Valid values are 'GRID', 'LAND', 'COLS', 'PFTS'. For example, if one dimensional output is selected for tape 3 and HIST_TYPE1D_PERTAPE is set to 'COLS', then all the fields will have 1d column output. If the specified one dimensional output type is not defined for a given field, output values will be set to 1.e36 for that field.

type

char*4

mode

all

default

blank

name

HIST_EMPTY_HTAPES

description

If set to true, all the history tapes are empty by default. Only variables explicitly listed by the user will be output.

type

logical

mode

all

default

.FALSE.

name

HIST_FINCL1...HIST_FINCL6(max_flds)

description

List of fields to include on the respective history tape. See tables 9-16 for the list of default fields on the primary history tape. Namelist specification can take one of two forms. The user may specify only the name of the field to be included on the history tape (in which case the default time averaging for that field will be used). For example, HIST_FINCL2='TV', will add the field TV to the second history tape with whatever default time averaging was specified for TV. Alternatively, the user may specify the field name, followed by a : followed by the time averaging flag desired (valid flags are 'I' for instantaneous, 'A' for average, 'M' for minimum, and 'X' for maximum). For example, HIST_FINCL2='TV:I'' will add the field TV with instantaneous output to the second history tape.

type

char*34

mode

all

default

blank

name

HIST_FEXCL1..HIST_FEXCL6(max_flds)

description

List of fields to exclude from the respective history tape. The field name must appear in the Master Field List. Currently, there is one default history tape, (the primary tape is monthly averaged). See tables 9-16 for more details.

type

char*32

mode

all

default

blank

name

MSS_IRT

description

Mass store retention period (days) for output datasets (see ex. 4)

type

integer

mode

offline, ccsm (obtained from atm in cam mode)

default

0 (i.e., history files will be written to local disk, not the NCAR Mass-Store)

name

MSS_WPASS

description

Mass store write password for output datasets.

type

char*8

mode

all

default

blank

name

RPNTPATH

description

Full unix pathname of the local restart pointer file.

type

char*256

mode

all

default

lnd.CASEID.rpointer in home directory

The model writes its own history, restart and initial files. History files are in netCDF file format and contain model data values written at user specified frequencies during a model run. Each field has a default time averaging flag determining how that field will be accumulated in time over a given history interval. The choices are to record averaged, instantaneous, maximum, or minimum values. The user may overwrite this default setting via the namelist variable HIST_FINCLX where X can equal 1 to 6. If the user wishes to see a field written at more than one output frequency (e.g. daily and hourly), additional history files must be declared containing that field. By default, CLM2.1 produces a monthly averaged primary history file and allows the user to define up to five auxiliary history files. All files contain grid averaged data unless the namelist variable HIST_DOV2XY is set to false for a given file. Primary history files contain the string 'h0', whereas auxiliary history files contain the string 'h1', 'h2', 'h3','h4' and 'h5'. Monthly averaged history files may be produced for history tape ``t'' by setting HIST_NHTFRQ(t) to zero. By default, all time averaged fields on tape t will be output over the period beginning from the first timestep of the current month up to and including the last timestep of that month. Each monthly history file will contain exactly one time slice of data, regardless of the value of HIST_MFILT(t).

The model will also periodically create initial netCDF datasets containing only one dimensional instantaneous values of initial data fields. The model produces initial datasets either yearly, monthly, or not at all depending on the setting of the namelist variable HIST_CRTINIC (the default setting is ``YEARLY''). These datasets can be utilized as ``spun-up'' initial conditions.

Restart files are in binary format and can be used only for restart or branch runs from previous model simulations. Whenever a restart file is written, a corresponding local disk restart pointer file is overwritten. The restart pointer file contains the name of the latest model restart file. By default, the restart pointer file is placed in the user's home directory under the name, lnd.CASEID.rpointer. The user may modify the full pathname of the restart pointer file via the setting of the namelist variable RPNTPATH.

The following table specifies the naming convention used for output files. In this table the string yyyy refers to the model year, mm refers to the model month, dd is the model day and sssss corresponds to seconds into the model day. Note that for non-monthly history files, yyyy-mm-dd-sssss corresponds to the first timestamp of data on the file. CASEID is the case identifier set via the namelist input.

CASEID.clm2.r.yyyy-mm-dd-sssss

restart files

CASEID.clm2.i.yyyy-mm-dd-sssss.nc

initial files

CASEID.clm2.h[012345].yyyy-mm.nc

monthly average history files

CASEID.clm2.h[012345].yyyy-mm-dd-sssss.nc

non-monthly history files

History, restart and initialization files can be archived on the NCAR Mass Storage System (MSS) if the namelist variable MSS_IRT is set to a value greater than zero. History, restart and initial files are archived as follows (where USERNAME is the upper-case equivalent of the user's login name, i.e., the user's root directory on the MSS):

history files

/USERNAME/csm/CASEID/lnd/hist

restart files

/USERNAME/csm/CASEID/lnd/rest

initial files

/USERNAME/csm/CASEID/lnd/init