GEOS GCM Quick Start: Difference between revisions

Line 295:

The post-processing script will generate the archiving and plotting scripts as it runs. The setup script that you ran also creates an experiment home directory (''HOMDIR'') as either in <code>~''USERID''/geos5/''EXPID''</code> (if you accepted the default) or in <code>/discover/nobackup/''USERID''/''EXPID''</code> (if you followed the above advice) containing the run scripts and GEOS resource (<code>.rc</code>) files.

== Running GEOS-5 ==

== Running GEOS ==

Before running the model, there is some more setup to be completed. The run scripts need some environment variables set in <code>~/.cshrc</code> (regardless of which login shell you use -- the GEOS-5 scripts use <code>csh</code>). Here are the minimum contents of a <code>.cshrc</code>:

Before running the model, there is some more setup to be completed. The run scripts need some environment variables set in <code>~/.cshrc</code> (regardless of which login shell you use -- the GEOS scripts use <code>csh</code>). Here are the minimum contents of a <code>.cshrc</code>:

umask 022

Line 325:

The contents of the output files (including which variables get saved) may be configured in the <code>''HOMEDIR''/HISTORY.rc</code> -- a good description of this file may be found at http://modelingguru.nasa.gov/clearspace/docs/DOC-1190 .

== What Happens During a Run ==

When the script <code>gcm_run.j</code> starts running, it creates a directory called <code>scratch</code> and copies or links into it the model executable, rc files, restarts and boundary conditions necessary to run the model. It also creates a directory for each of the output collections (in the default setup with the suffix <code>geosgcm_</code>) in the directory <code>holding</code> for before post-processing, and in the experiment directory for after post-processing. It also tars the restarts and moves the tarball to the <code>restarts</code> directory.

Then the executable <code>GEOSgcm.x</code> is run in the <code>scratch</code> directory, starting with the date in <code>cap_restart</code> and running for the length of a segment. A segment is the length of model time that the model integrates before returning, letting <code>gcm_run.j</code> do some housekeeping and then running another segment. A model job will typically run a number of segments before trying to resubmit itself, hopefully before the allotted wallclock time of the job runs out.

The processing that the various batch jobs perform is illustrated below:

[[Image:F2.5-job-diagram002.png]]

Each time a segment ends, <code>gcm_run.j</code> submits a post-processing job before starting a new segment or exiting. The post-processing job moves the model output from the <code>scratch</code> directory to the respective collection directory under <code>holding</code>. Then it determines whether there is a enough output to create a monthly or seasonal mean, and if so, creates them and moves them to the collection directories in the experiment directory, and then tars up the daily output and submits an archiving job. The archiving job tries to move the tarred daily output, the monthly and seasonal means and any tarred restarts to the user's space in <code>archive</code> filesystem. The post-processing script also determines (assuming the default settings) whether enough output exists to create plots; if so, a plotting job is submitted to the queue. The plotting script produces a number of pre-determined plots as <code>.gif</code> files in the <code>plot_CLIM</code> directory in the experiment directory.

You can check on jobs in the queue with <code>qstat</code>. The jobs associated with the run will be named with the experiment name appended with the type of job it is: RUN, POST, ARCH or PLT.

As explained above, the contents of the <code>cap_restart</code> file determine the start of the model run in model time, which determines boundary conditions and the times stamps of the output. The end time may be set in <code>CAP.rc</code> with the property <code>END_DATE</code> (format ''YYYYMMDD HHMMSS'', with a space), though integration is usually leisurely enough that one can just kill the job or rename the run script <code>gcm_run.j</code> so that it is not resubmitted to the job queue.

=== Tuning a run ===

Most of the other properties in <code>CAP.rc</code> are discussed elsewhere, but two that are important for understanding how the batch jobs work are <code>JOB_SGMT</code>, the length of the segment, and <code>NUM_SGMT</code>, the number of segments that the job tries to run before resubmitting itself and exiting. <code>JOB_SGMT</code> is in the format of ''YYYYMMDD HHMMSS'' (but usually expressed in days) and <code>NUM_SGMT</code> as an integer, so the multiple of the two is the total model time that a job will attempt to run. It may be tempting to just run one long segment, but much housekeeping is done between segments, such as saving state in the form of restarts and spawning archiving jobs that keep your account from running over disk quota. So to tune for the maximum number of segments in a job, it is usually best to manipulate <code>JOB_SGMT</code>.

== Determining Output: <code>HISTORY.rc</code> ==

The contents of the the file <code>HISTORY.rc</code> (in your experiment <code>HOME</code> directory) tell the model what and how to output its state and diagnostic fields. The default <code>HISTORY.rc</code> provides many fields as is, but you may want to modify it to suit your needs.

===File format===

The top of a default <code>HISTORY.rc</code> will look something like this:

<pre>

EXPID: myexp42

EXPDSC: this_is_my_experiment

COLLECTIONS: 'geosgcm_prog'

'geosgcm_surf'

'geosgcm_moist'

'geosgcm_turb'

</pre>

[....]

The attribute <code>EXPID</code> must match the name of the experiment <code>HOME</code> directory; this is only an issue if you copy the <code>HISTORY.rc</code> from a different experiment. The <code>EXPDSC</code> attribute is used to label the plots. The <code>COLLECTIONS</code> attribute contains list of strings indicating the output collections to be created. The content of the individual collections are determined after this list. Individual collections can be "turned off" by commenting the relevant line with a <code>#</code>.

The following is an example of a collection specification:

<pre>

geosgcm_prog.template: '%y4%m2%d2_%h2%n2z.nc4',

geosgcm_prog.archive: '%c/Y%y4',

geosgcm_prog.format: 'CFIO',

geosgcm_prog.frequency: 060000,

geosgcm_prog.resolution: 144 91,

geosgcm_prog.vscale: 100.0,

geosgcm_prog.vunit: 'hPa',

geosgcm_prog.vvars: 'log(PLE)' , 'DYN' ,

geosgcm_prog.levels: 1000 975 950 925 900 875 850 825 800 775 750 725 700 650 600 550 500 450 400 350 300 250 200 150 100 70 50 40 30 20 10 7 5 4 3 2 1 0.7 0.5 0.4 0.3 0.2

0.1 0.07 0.05 0.04 0.03 0.02,

geosgcm_prog.fields: 'PHIS' , 'AGCM' ,

'T' , 'DYN' ,

'PS' , 'DYN' ,

'ZLE' , 'DYN' , 'H' ,

'OMEGA' , 'DYN' ,

'Q' , 'MOIST' , 'QV' ,

::

</pre>

The individual collection attributes are described below, but what users modify the most are the <code>fields</code> attribute. This determines which exports are saved in the collection. Each field record is a string with the name of an export from the model followed by a string with the name of the gridded component which exports it, separated by a comma. The entries with a third column determine the name by which that export in saved in the collection file when the name is different from that of the export.

There is a good description of available collection options at Modeling Guru: https://modelingguru.nasa.gov/docs/DOC-1190

===What exports are available?===

To add export fields to the <code>HISTORY.rc</code> you will need to know what fields the model provides, which gridded component provides them, and their name. The most straightforward way to do this is to use <code>PRINTSPEC</code>. The setting for <code>PRINTSPEC</code> is in the file <code>CAP.rc</code>. By default the line looks like so:

PRINTSPEC: 0 # (0: OFF, 1: IMPORT & EXPORT, 2: IMPORT, 3: EXPORT)

Setting <code>PRINTSPEC</code> to 3 will make the model send to standard output a list of exports available to <code>HISTORY.rc</code> in the model's current configuration, and then exit without integrating. The list includes each export's gridded component and short name (both necessary to include in <code>HISTORY.rc</code>), long (descriptive) name, units, and number of dimensions. Note that run-time options can affect the exports available, so see to it that you have those set as you intend. The other <code>PRINTSPEC</code> values are useful for debugging.

While you can set <code>PRINTSPEC</code>, submit <code>sbatch gcm_run.j</code>, and get the export list as part of PBS standard output, there are quicker ways of obtaining the list. One way is to run it as a single column model on a single processor, as explained in [[Jason Single Column Model]]. Another way is to run it in an existing experiment. In the <code>scratch</code> directory of an experiment that has already run, change <code>PRINTSPEC</code> in <code>CAP.rc</code> as above. Then, in the file <code>AGCM.rc</code>, change the values of <code>NX</code> and <code>NY</code> (near the beginning of the file) to 1. Then, from an interactive job (one processor will suffice), run the executable <code>GEOSgcm.x</code> in <code>scratch</code>. You will need to run <code>source src/g5_modules</code> in the model's build tree to set up the environment. The model executable will simply output the export list to <code>stdout</code>.

===Outputting Derived Fields===

In addition to writing export fields created by model components (we will refer to these as model fields), the user may specify new fields that will be evaluated using the MAPL parser. These will be referred to as derived fields in the following discussion. The derived fields are evaluated using an expression that involves other fields in the collection as variables. The expression is evaluated element by element to create a new field. Derived fields are specified like a regular field from a gridded component in a history collection with 3 comma separated strings. The difference is now that in place of a variable name string, an expression string that will be evaluated is entered. Following this comes the string specifying the gridded component. You MUST put a string here, which should be the name of a gridded component. Finally a string MUST be entered which is the name of the new variable. This will be the name of the variable in the output file. In general the expression entered will involve variables, functions, and real numbers. The derived fields are evaluated before time and spatial (vertical and horizontal) averaging.

Here are some rules about expressions

#Fields in expression can only be model fields.

#If the model field has an alias you must use the alias in the expression.

#You can not mix center and edge fields in an expression. You can mix 2D and 3D fields if the 3D fields are all center or edge. In this case each level of the 3D field operated with the 2D field. Another way to think of this is that in an expression involving a 2D and 3D field the 2D field gets promoted to a 3D field with the same data in each level.

#When parsing an expression the parser first checks if the fields in an expression are part of the collection. Any model field in a collection can be used in an expression in the same collection. However, there might be cases where you wish to output an expression but not the model fields used in the expression. In this case if the parser does not find the field in the collection it checks the gridded component name after the expression for the model field. If the field is found in the gridded component it can use it in the expression. Note that if you have an expression with two model fields from different gridded components you can not use this mechanism to output the expression without outputting either field. One of them must be in the collection.

#The alias of an expression can not be used in a subsequent expression.

Here are the rules for the expressions themselves

The following can appear in the expression string

#The function string can contain the following mathematical operators +, -, *, /, ^ and ()

#Variable names - Parsing of variable names is case sensitive.

#The following single argument fortran intrinsic functions and user defined functions are implmented: exp, log10, log, sqrt, sinh, cosh, tanh, sin, cos, tan, asin, acos, atan, heav (the Heaviside step function). Parsing of functions is case insensitive.

#Integers or real constants. To be recognized as explicit constants these must conform to the format [+|-][nnn][.nnn][e|E|d|D][+|-][nnn] where nnn means any number of digits. The mantissa must contain at least one digit before or following an optional decimal point. Valid exponent identifiers are 'e', 'E', 'd' or 'D'. If they appear they must be followed by a valid exponent!

#Operations are evaluated in the order

##expressions in brackets

##-X unary minux

##X^Y exponentiation

##X*Y X/Y multiplicaiton and division

##A+B X-Y addition and subtraction

In the following example we create a collection that has three derived fields, the magnitude of the wind, the temperature in farenheit, and temperature cubed:

<pre>

geosgcm_prog.template: '%y4%m2%d2_%h2%n2z.nc4',

geosgcm_prog.archive: '%c/Y%y4',

geosgcm_prog.format: 'CFIO',

geosgcm_prog.frequency: 060000,

geosgcm_prog.resolution: 144 91,

geosgcm_prog.fields: 'U' , 'DYN' ,

'V' , 'DYN' ,

'T' , 'DYN' ,

'sqrt(U*U+V*V)' , 'DYN' , 'Wind_Magnitude' ,

'(T-273.15)*1.8+32.0' , 'DYN' , 'TF' ,

'T^3' , 'DYN', 'T3' ,

::

</pre>

----

@@ Line 295: / Line 295: @@
 The post-processing script will generate the archiving and plotting scripts as it runs.  The setup script that you ran also creates an experiment home directory (''HOMDIR'') as either in <code>~''USERID''/geos5/''EXPID''</code> (if you accepted the default) or in <code>/discover/nobackup/''USERID''/''EXPID''</code> (if you followed the above advice) containing the run scripts and GEOS resource (<code>.rc</code>) files.
-== Running GEOS-5 ==
+== Running GEOS ==
-Before running the model, there is some more setup to be completed.  The run scripts need some environment variables set in <code>~/.cshrc</code> (regardless of which login shell you use -- the GEOS-5 scripts use <code>csh</code>).  Here are the minimum contents of a <code>.cshrc</code>:
+Before running the model, there is some more setup to be completed.  The run scripts need some environment variables set in <code>~/.cshrc</code> (regardless of which login shell you use -- the GEOS scripts use <code>csh</code>).  Here are the minimum contents of a <code>.cshrc</code>:
   umask 022
@@ Line 325: / Line 325: @@
 The contents of the output files (including which variables get saved) may be configured in the  <code>''HOMEDIR''/HISTORY.rc</code> -- a good description of this file may be found at http://modelingguru.nasa.gov/clearspace/docs/DOC-1190 .
+== What Happens During a Run ==
+When the script <code>gcm_run.j</code> starts running, it creates a directory called  <code>scratch</code> and copies or links into it the model executable, rc files, restarts and boundary conditions necessary to run the model.  It also creates a directory for each of the output collections (in the default setup with the suffix <code>geosgcm_</code>) in the directory <code>holding</code> for before post-processing, and in the experiment directory for after post-processing.  It also tars the restarts and moves the tarball to the <code>restarts</code> directory.
+Then the executable  <code>GEOSgcm.x</code> is run in the <code>scratch</code> directory, starting with the date in  <code>cap_restart</code> and running for the length of a segment.  A segment is the length of model time that the model integrates before returning, letting <code>gcm_run.j</code> do some housekeeping and then running another segment.  A model job will typically run a number of segments before trying to resubmit itself, hopefully before the allotted wallclock time of the job runs out.
+The processing that the various batch jobs perform is illustrated below:
+[[Image:F2.5-job-diagram002.png]]
+Each time a segment ends, <code>gcm_run.j</code> submits a post-processing job before starting a new segment or exiting.  The post-processing job moves the model output from the  <code>scratch</code> directory to the respective collection directory under  <code>holding</code>.  Then it determines whether there is a enough output to create a monthly or seasonal mean, and if so, creates them and moves them to the collection directories in the experiment directory, and then tars up the daily output and submits an archiving job.  The archiving job tries to move the tarred daily output, the monthly and seasonal means and any tarred restarts to the user's space in <code>archive</code> filesystem.  The post-processing script also determines (assuming the default settings) whether enough output exists to create plots; if so, a plotting job is submitted to the queue.  The plotting script produces a number of pre-determined plots as <code>.gif</code> files in the <code>plot_CLIM</code> directory in the experiment directory.
+You can check on jobs in the queue with <code>qstat</code>.  The jobs associated with the run will be named with the experiment name appended with the type of job it is: RUN, POST, ARCH or PLT.
+As explained above, the contents of the <code>cap_restart</code> file determine the start of the model run in model time, which determines boundary conditions and the times stamps of the output.  The end time may be set in <code>CAP.rc</code> with the property <code>END_DATE</code>  (format ''YYYYMMDD HHMMSS'', with a space), though integration is usually leisurely enough that one can just kill the job or rename the run script <code>gcm_run.j</code> so that it is not resubmitted to the job queue.
+=== Tuning a run ===
+Most of the other properties in <code>CAP.rc</code> are discussed elsewhere, but two that are important for understanding how the batch jobs work are <code>JOB_SGMT</code>, the length of the segment, and <code>NUM_SGMT</code>, the number of segments that the job tries to run before resubmitting itself and exiting.  <code>JOB_SGMT</code> is in the format of ''YYYYMMDD HHMMSS'' (but usually expressed in days) and <code>NUM_SGMT</code> as an integer, so the multiple of the two is the total model time that a job will attempt to run.  It may be tempting to just run one long segment, but much housekeeping is done between segments, such as saving state in the form of restarts and spawning archiving jobs that keep your account from running over disk quota.  So to tune for the maximum number of segments in a job, it is usually best to manipulate <code>JOB_SGMT</code>.
+== Determining Output: <code>HISTORY.rc</code> ==
+The contents of the the file <code>HISTORY.rc</code> (in your experiment <code>HOME</code> directory) tell the model what and how to output its state and diagnostic fields.  The default <code>HISTORY.rc</code> provides many fields as is, but you may want to modify it to suit your needs.
+===File format===
+The top of a default <code>HISTORY.rc</code> will look something like this:
+<pre>
+EXPID:  myexp42
+EXPDSC: this_is_my_experiment
+COLLECTIONS: 'geosgcm_prog'
+             'geosgcm_surf'
+             'geosgcm_moist'
+             'geosgcm_turb'
+</pre>
+[....]
+The attribute <code>EXPID</code> must match the name of the experiment <code>HOME</code> directory; this is only an issue if you copy the  <code>HISTORY.rc</code> from a different experiment.  The <code>EXPDSC</code> attribute is used to label the plots.  The <code>COLLECTIONS</code> attribute contains list of strings indicating the output collections to be created.  The content of the individual collections are determined after this list.  Individual collections can be "turned off" by commenting the relevant line with a <code>#</code>.
+The following is an example of a collection specification:
+<pre>
+  geosgcm_prog.template:  '%y4%m2%d2_%h2%n2z.nc4',
+  geosgcm_prog.archive:   '%c/Y%y4',
+  geosgcm_prog.format:    'CFIO',
+  geosgcm_prog.frequency:  060000,
+  geosgcm_prog.resolution: 144 91,
+  geosgcm_prog.vscale:     100.0,
+  geosgcm_prog.vunit:     'hPa',
+  geosgcm_prog.vvars:     'log(PLE)' , 'DYN'          ,
+  geosgcm_prog.levels:     1000 975 950 925 900 875 850 825 800 775 750 725 700 650 600 550 500 450 400 350 300 250 200 150 100 70 50 40 30 20 10 7 5 4 3 2 1 0.7 0.5 0.4 0.3 0.2
+.1 0.07 0.05 0.04 0.03 0.02,
+  geosgcm_prog.fields:    'PHIS'     , 'AGCM'         ,
+                          'T'        , 'DYN'          ,
+                          'PS'       , 'DYN'          ,
+                          'ZLE'      , 'DYN'          , 'H'   ,
+                          'OMEGA'    , 'DYN'          ,
+                          'Q'        , 'MOIST'        , 'QV'  ,
+                          ::
+</pre>
+The individual collection attributes are described below, but what users modify the most are the <code>fields</code> attribute.  This determines which exports are saved in the collection.  Each field record is a string with the name of an export from the model followed by a string with the name of the gridded component which exports it, separated by a comma.  The entries with a third column determine the name by which that export in saved in the collection file when the name is different from that of the export.
+There is a good description of available collection options at Modeling Guru: https://modelingguru.nasa.gov/docs/DOC-1190
+===What exports are available?===
+To add export fields to the <code>HISTORY.rc</code> you will need to know what fields the model provides, which gridded component provides them, and their name.  The most straightforward way to do this is to use <code>PRINTSPEC</code>.  The setting for  <code>PRINTSPEC</code> is in the file <code>CAP.rc</code>.  By default the line looks like so:
+ PRINTSPEC: 0  # (0: OFF, 1: IMPORT & EXPORT, 2: IMPORT, 3: EXPORT)
+Setting <code>PRINTSPEC</code> to  3 will make the model send to standard output a list of exports available to <code>HISTORY.rc</code> in the model's current configuration, and then exit without integrating. The list includes each export's gridded component and short name (both necessary to include in <code>HISTORY.rc</code>), long (descriptive) name, units, and number of dimensions.  Note that run-time options can affect the exports available, so see to it that you have those set as you intend.  The other <code>PRINTSPEC</code> values are useful for debugging.
+While you can set  <code>PRINTSPEC</code>, submit <code>sbatch gcm_run.j</code>, and get the export list as part of PBS standard output, there are quicker ways of obtaining the list.  One way is to run it as a single column model on a single processor, as explained in [[Jason Single Column Model]].  Another way is to run it in an existing experiment.  In the <code>scratch</code> directory of an experiment that has already run, change <code>PRINTSPEC</code> in  <code>CAP.rc</code> as above.  Then, in the file <code>AGCM.rc</code>, change the values of <code>NX</code> and <code>NY</code> (near the beginning of the file) to 1.  Then, from an interactive job (one processor will suffice), run the executable <code>GEOSgcm.x</code> in <code>scratch</code>.  You will need to run <code>source src/g5_modules</code> in the model's build tree to set up the environment.  The model executable will simply output the export list to <code>stdout</code>.
+===Outputting Derived Fields===
+In addition to writing export fields created by model components (we will refer to these as model fields), the user may specify new fields that will be evaluated using the MAPL parser. These will be referred to as derived fields in the following discussion. The derived fields are evaluated using an expression that involves other fields in the collection as variables. The expression is evaluated element by element to create a new field. Derived fields are specified like a regular field from a gridded component in a history collection with 3 comma separated strings. The difference is now that in place of a variable name string, an expression string that will be evaluated is entered. Following this comes the string specifying the gridded component. You MUST put a string here, which should be the name of a gridded component. Finally a string MUST be entered which is the name of the new variable. This will be the name of the variable in the output file. In general the expression entered will involve variables, functions, and real numbers. The derived fields are evaluated before time and spatial (vertical and horizontal) averaging.
+Here are some rules about expressions
+#Fields in expression can only be model fields.
+#If the model field has an alias you must use the alias in the expression.
+#You can not mix center and edge fields in an expression. You can mix 2D and 3D fields if the 3D fields are all center or edge. In this case each level of the 3D field operated with the 2D field. Another way to think of this is that in an expression involving a 2D and 3D field the 2D field gets promoted to a 3D field with the same data in each level.
+#When parsing an expression the parser first checks if the fields in an expression are part of the collection. Any model field in a collection can be used in an expression in the same collection. However, there might be cases where you wish to output an expression but not the model fields used in the expression. In this case if the parser does not find the field in the collection it checks the gridded component name after the expression for the model field. If the field is found in the gridded component it can use it in the expression. Note that if you have an expression with two model fields from different gridded components you can not use this mechanism to output the expression without outputting either field. One of them must be in the collection.
+#The alias of an expression can not be used in a subsequent expression.
+Here are the rules for the expressions themselves
+The following can appear in the expression string
+#The function string can contain the following mathematical operators +, -, *, /, ^ and ()
+#Variable names - Parsing of variable names is case sensitive.
+#The following single argument fortran intrinsic functions and user defined functions are implmented: exp, log10, log, sqrt, sinh, cosh, tanh, sin, cos, tan, asin, acos, atan, heav (the Heaviside step function). Parsing of functions is case insensitive.
+#Integers or real constants. To be recognized as explicit constants these must conform to the format [+|-][nnn][.nnn][e|E|d|D][+|-][nnn] where nnn means any number of digits. The mantissa must contain at least one digit before or following an optional decimal point. Valid exponent identifiers are 'e', 'E', 'd' or 'D'. If they appear they must be followed by a valid exponent!
+#Operations are evaluated in the order
+##expressions in brackets
+##-X      unary minux
+##X^Y  exponentiation
+##X*Y X/Y multiplicaiton and division
+##A+B X-Y addition and subtraction
+In the following example we create a collection that has three derived fields, the magnitude of the wind, the temperature in farenheit, and temperature cubed:
+<pre>
+  geosgcm_prog.template:  '%y4%m2%d2_%h2%n2z.nc4',
+  geosgcm_prog.archive:   '%c/Y%y4',
+  geosgcm_prog.format:    'CFIO',
+  geosgcm_prog.frequency:  060000,
+  geosgcm_prog.resolution: 144 91,
+  geosgcm_prog.fields:    'U'             , 'DYN'          ,
+                          'V'             , 'DYN'          ,
+                          'T'             , 'DYN'          ,
+                          'sqrt(U*U+V*V)' , 'DYN'          , 'Wind_Magnitude'   ,
+                          '(T-273.15)*1.8+32.0' , 'DYN'    , 'TF' ,
+                          'T^3'           , 'DYN',         'T3' ,
+                          ::
+</pre>
 ----