4.1 Specification of run length, run type and initial run date

The following list specifies namelist variables associated with the definition of run case names, run types (restart, initial or branch), model time step, and initial run date.

An initial run starts the model from either initial conditions that are set internally in the code (referred to as arbitrary initial conditions) or from an initial conditions dataset (see namelist variable FINIDAT) that enables the model to start from a spun-up state.

A restart run is an exact continuation of a previous simulation from its point of termination. Output from a restart run should be bit-for-bit the same as if the previous simulation had not stopped. Run control variables set in the namelist must be the same as in the run that is being restarted.

A branch run is a new case that uses a restart dataset from a previous simulation to begin the integration. For a branch run, the length of the history interval and the output history fields do not have to be the same as in the control simulation. For example, the branching option can be used to output selected fields more frequently than was the case in the original run or to add new auxiliary history files to the model run.

name

CASEID

description

Case name (short identifier for run) (see ex. 1,2,3).

type

char*32

mode

offline, ccsm (obtained from atm in cam mode)

default

required (must be changed for branch run)

name

CTITLE

description

Case title for use within history files (long identifier).

type

char*80

mode

offline, ccsm (obtained from atm in cam mode)

default

blank

name

NSREST

description

Run type (0 for initial run, 1 for restart, 3 for branch) (see ex. 1,2,3).

type

integer

mode

offline, ccsm (obtained from atm in cam mode)

default

required

name

DTIME

description

Model time step (seconds) (see ex. 1).

type

integer

mode

offline, must agree with CAM2 in ccsm mode, obtained from CAM2 in cam mode

default

required (suggested range: 1200-3600 s)

name

NELAPSE

description

Elapsed run time in model time steps (positive) or days (negative) (see ex. 2).

type

integer

mode

offline (obtained from atm/coupler in cam/ccsm mode, respectively)

default

required (if NESTEP not set)

name

NESTEP

description

Ending run time in model time steps (positive) or days (negative) (see ex. 1).

type

integer

mode

offline (obtained from atm/coupler in cam/ccsm mode, respectively)

default

required (if NELAPSE not set)

name

START_YMD

description

Start date of run (yyyymmdd format) (see ex. 1).

type

integer

mode

offline, ccsm (obtained from atm in cam mode)

default

required

name

START_TOD

description

Start time of day of run (seconds) (see ex. 1).

type

integer

mode

offline, ccsm (obtained from atm in cam mode)

default

0