P_ Variables
(POLAIR)


P_

The POLAIR system scripts are executed according to the setting of the POLAIR environmental variables. These variables are prefixed by P_ and exits in two basic categories. First, those which are usually automatically set and in which the user, generally, need not adjust. The variables in this category are:

POLAIR P_
Environmental
Variables		 Values Comment
P_ACCESS_CODE string
P_ACTIVE {.TRUE.,.FALSE.} Current running status
P_BATCH_LOG_DIR ~/polair/data/.../log Location of log file of completed batch job
P_BATCH_JOB {.TRUE.,.FALSE.} Current batch running status
P_DISK_SPACE Amount of disk space available
P_GRADS_PS_TRANS GrADS postscript translator path
P_IMAGEMAGICK Imagemagick path
P_IMAGES Captured-images path
P_LOCAL_HOST
P_LOCAL_NODE
P_MAKE {make,dmake,gmake} Serial or distributed makefiles
P_MASTER_HOST Host of master code
P_MASTER_NODE Node of master code
P_MODEL Modeling system
P_MPI_NUM_PE > 1 Number of MPI processors
P_OMP_NUM_PE > 1 Number of OMP processors
P_OS Operating system
P_PRINTER Local printer
P_REMOTE_HOST
P_REMOTE_NODE
P_ROOT Root directory
P_USER User's name
P_USER_EMAIL User's email address (e.g., for batch notification)
P_VERSION

The second group of POLAIR environmental variables are those prefixed by P_EXPT_ and of which the user generally adjusts the values prior to running the model. Most of these are set in the file ~/polair/code/scripts/set_P_variables.sh. These variables are:

POLAIR P_EXPT_
Environmental
Variables		 Values Comment
P_EXPT_CONTEXT string Default MASTER
P_EXPT_ID_NEW {001...999}
P_EXPT_ID_OLD {000...998}
P_EXPT_ID_FRS {001...998}
P_EXPT_INCLUDE_COUPLER 1
P_EXPT_INCLUDE_ATMOS {0,1,2}
P_EXPT_INCLUDE_DATA_ANAL {0,1} Mutually exclusive to model run
P_EXPT_INCLUDE_EXCHANGE {0,1} Mutually exclusive to model run
P_EXPT_INCLUDE_FGI {0,1} Set only by GrADS software
P_EXPT_INCLUDE_GLACIER {0,1,2}
P_EXPT_INCLUDE_ICE {0,1,2}
P_EXPT_INCLUDE_LAND {0,1,2}
P_EXPT_INCLUDE_MAGNET {0,1,2}
P_EXPT_INCLUDE_OCEAN {0,1,2}

Within the FORTRAN execution environment, all the UNIX environment P_ variables are replaced by their equivalent names, except the prefix C_ replaces the P_ prefix. For example, the variable P_MODEL becomes C_MODEL.

Context

Each experiment has set by the user a unique POLAIR environmental variable P_EXPT_CONTEXT. It is set in the script .../polair/code/scripts/set_P_variables.sh. It is a string identifier that describes the particular context of an experiment, or suite of experiments. By default it is set as having the value MASTER.

If a user is carrying out an experiment that involves relatively minor modifications to the code, then instead of creating a new separate version of the code, it is easier to assign the variable P_EXPT_CONTEXT and place conditional statements in the FORTRAN code that are only activate for the user's own particular context. Other users, with other contexts, are unaffected by such code modifications. As an example, consider the file c_orography.f in which the user, depending on his/her context may want to generate on orography that is different from the default case, or that of other contexts.

IDs

Each experiment has a unique pair of experiment identification numbers (IDs) assigned to it by the user P_EXPT_ID_NEW and P_EXPT_ID_OLD. They are set in the script .../polair/code/scripts/set_P_variables.sh.

The POLAIR environmental variable P_EXPT_ID_NEW is to be assigned as a unique, three-digit identifier of the new experiment about to be carried out. The value must be between 000 and 999.

The POLAIR environmental variable P_EXPT_ID_OLD also must have a value must be between 000 and 999. A value of 000 means that the new experiment is in fact an initialization run, while a value greater than 000 means that the new experiment is a restart from a previous experiment, in particular, one having its P_EXPT_ID_NEW assigned as the current P_EXPT_ID_OLD.

There are certain special combinations of settings for P_EXPT_ID_NEW and P_EXPT_ID_OLD. Choosing the P_EXPT_ID_NEW as 001 and P_EXPT_ID_OLD as 000 causes the system not to integrate the submodels forward in time, but only to create the forcing fields.

P_EXPT_ID_NEW is set to 000 exclusively for a data exchange. In this case P_EXPT_ID_OLD also has to be set to 000.

A graphical depiction of the various settings of the IDs is given here.

An additional POLAIR environmental variable, currently under development, is P_EXPT_ID_FRS. Setting this variable to an integer greater than 000 activates the Flow-Relaxation Scheme. This scheme allows for nesting of the current model domain for experiment P_EXPT_ID_NEW within a larger, previously defined domain as carried out in experiment having ID as P_EXPT_ID_FRS.

Data Exchange

If P_EXPT_INCLUDE_DATA_EXCHANGE is set to 1, a data file is converted into a format suitable for the model. The name of the input and output files should be set in the script io_files.sh. Recall that both P_EXPT_ID_NEW and P_EXPT_ID_OLD have to be set to 000.

Data Analysis

If P_EXPT_INCLUDE_DATA_ANAL is set to 1, the output files of P_EXPT_ID_NEW will contain the result of an analysis of the data from P_EXPT_ID_OLD. Currently, three types of analysis are available, comparison, EOFs, or wavelets. You choose which one by setting the appropriate switch in namelist_data_anal.nl in the namelist directory (cd n or cd $n).


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© David Holland.
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