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Running the Model


To run the model, go to the workspace directory work. This directory contains copies of scripts used to execute the model, as well run parameter files used as input to the model. These run parameter files include:
This ASCII file is created by the shell scripts used to execute the model. As it is copied of the user-controlled parameters given in the run execution script, the user will not have to directly access the file.
This binary file is more or less a ``snapshot'' of all prognostic model variables, and is read by QTCM1 as the initial conditions in a model run if the mrestart execution shell script variable is set to ``1''. See the discussion of variable mrestart on page gif for information on an important caveat to this file.
This binary file is written by QTCM1 at the end of a model run, and is more or less a snapshot of all prognostic variables at that time. If renamed to qtcm.restart, this file can be used as the initial conditions of a future model run. See the discussion of variable mrestart on page gif for information on an important caveat to this file.
This ASCII file contains the values of various parameters and coefficients used by QTCM1, and is a copy of the same file in src. See Section 1.4.1 for more information on this file. See Chapter 3 for a discussion of the physics behind the variables in this file.

The package comes with a number of different C shell scripts that control different ways of model execution. ``Original'' versions of these scripts are found in the directory scripts, while ``working'' copies are located in work. These scripts include:
Makes the ``first-time'' run of QTCM1. This creates a qtcm.restart file that can be used to shorten the ``spin-up'' of the model. This script uses monthly climatological SSTs as forcing.
Runs QTCM1 using SSTs interpolated from observed values. This option is available for dates from the first day of November 1981-last day of March 1998.
Runs QTCM1 using monthly climatological SSTs.
Executes a brief run of QTCM1 to test code-machine compatibility.

To run the model, change the user-controlled parameters in one of the above scripts to suit your purposes, then execute the scripts by typing the script name at the command line. After you first port the model over to your computer, you should run to confirm that the model will compile and run correctly on your machine. Next, run the model a year or so with climatological SST to create a qtcm.restart initial conditions file that will serve to shorten the spin-up time of the model. The script is set-up to do this. Finally, conduct an actual model run by executing or, as appropriate.

The model execution scripts govern the execution of the model by first defining the major user-controlled parameters under the script comment title ``Generate the user control parameters tex2html_wrap_inline1812 '' These parameters are then input as a FORTRAN namelist so any parameter undefined in the script will take-on the default value given in the subroutine DriveInit in driver.f. Finally, the script compiles and links the version of the code found in sub-directory src using the file ``makefile'' in src (see Section 1.4.3 for more information about the makefiles included with this QTCM1 package), moves the resulting executable from src to work, and executes the program in work. As it runs, the program writes out diagnostic messages (such as the number of simulation days completed) to the screen and to a file in directory work called log.

Below is an explanation of the user-controlled variables in the execution scripts. Default values for these user-controlled variables are defined in the subroutine DriverInit in driver.f.:

Path and name of the directory containing the boundary condition datasets. See Section 1.4.1 for details.
Path and name of the directory containing the SST datasets. See Section 1.4.1 for details.
Path and name of the directory that the output data will be written to. See Section 1.4.2 for details.
Land-interactive indicator: landon=1 (the default) means land is interactive. Other values of landon mean the land is treated like ocean with a fake SST provided from the SST files. Since an interactive land has more freedom, it's more prone to be unstable in the spin-up process, and it has spin-up time longer than the atmosphere by several months. Our recommendation is to run the model with land ``off'' for the first time ( is set with such a setting). However, QTCM1 seems to have little of this problem.
Model running mode: Affects how SST is fetched and how solartop evolves. Variable is an alphanumeric string. There are three mode options:
Starting date for the model (note year0 includes the millennium and century). For perpetual and seasonal cases, year0 can be any value between 1001 and 9998. However, note that year0 should be chosen such that during the entire length of the model run, the model year never exceeds 9998. Type INTEGER. Note: 1 year tex2html_wrap_inline1814 360 days in QTCM1.
Model runs from day 1 to lastday. Type INTEGER.
Ocean-atmosphere coupling interval (days). Must be greater than or equal to 1. Type INTEGER.
No output for the first noout days; useful for spin-up. Type INTEGER.
Mean output every ntout days. See Section 1.4.2 for more details. Minimum value is 1. Type INTEGER.
Instantaneous output every ntouti days. See Section 1.4.2 for more details. Minimum value is 1. Type INTEGER.
  Flag controlling whether to use qtcm.restart. If mrestart=1 (the default), model uses file qtcm.restart as initial condition (it is recommended to always use this option, except for the first time when you need to generate your own qtcm.restart file, together with the land off). Otherwise, the model will start from an initially unbalanced state; the spin-up time for the atmosphere is several days, and several months for land. Type INTEGER.

NB: Currently, restart using qtcm.restart is not ``perfect.'' This is because in the standard version, qtcm.restart.out does not save diagnosis of physics variables that are based on previous timesteps of those prognostic variables that are saved in qtcm.restart.out.

Time step for the atmosphere (sec). Type REAL tex2html_wrap_inline1816 8.
Dimensionless multiplier to set barotropic mode time step. The time step (sec) for the barotropic mode equals tex2html_wrap_inline1818 . Default value is 5. Type INTEGER.

Below is a sample of the user-controlled parameters section from a model execution script (e.g.

 title='QTCM test run'        !title
 bnddir='$QTCMROOT/bnddata'   !bnd. data other than SST
 SSTdir='$QTCMROOT/bnddata/SST_Reynolds_oi'    !where SST files are
 outdir='$QTCMROOT/proc'      !where output go
 landon=0                     !=0: land is like ocean with faked SST
 SSTmode='seasonal'           !decide what kind of SST to use
 year0 = 1001                 !starting year; must be between 1001 and 9998
 month0 = 1                   !starting month; 1 to 12
 day0 = 1                     !1 t0 30; each month has fixed length of 30 days
 lastday =  60                !model runs from day 1 to lastday (1yr=360day)
 interval = 1                 !ocean-atmo. coupling interval; integer days
 noout=0                      !no output for the first noout days
 ntout=30                     !output mean every ntout days
 ntouti=30                    !output instantaneous value every ntouti days
 mrestart=0                   !=1: restart using qtcm.restart
 dt=1200.                     !atmospheric model time step, real seconds

This sample defines a run using monthly climatological SST as forcing, beginning on January 1, and ending 60 days later at the end of February (ostensibly February ``30''). Land acts like an ocean with interpolated SST, the atmosphere-ocean coupling interval is one day, each atmospheric time step is 20 minutes, no ``spin-up'' file is used for initial conditions, and both mean and instantaneous output is written every 30 days (i.e. one month).

next up previous contents
Next: Processing and Viewing the Up: How to Make a Previous: How to Make a

Johnny Wei-Bing Lin
Wed Aug 26 16:58:31 PDT 1998