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Parallel Ocean Program (POP) User Guide

Version 2.1

Los Alamos National Laboratory

23 March 2003

LACC 99-18

Revised for CCSM4

National Center for Atmospheric Research

1 April 2010


This manual contains detailed instructions for operating the LANL version of the POP code. It should be the only manual needed to use LANL POP ''as is''. This version has been modified to include information on the CCSM4 version of the model.

Topics include:

Throughout this manual, it is assumed that the operating system is some variant of Unix. However, POP has been run on PCs under windows..

To keep the User's Guide as short as possible, LANL developers intend to create a Reference Manual for those users who seek an in-depth understanding of the code, such as would be needed to make changes to the source code. It contains a thorough description of the code, including the model equations, their discretized form, and the numerical methods used for their solution. The principal modules and subroutines are explained, the organization of the code is outlined, and the principal variables are defined.

Whenever POP is run, the version number and release date of the source code on your local system is output at the beginning of the log file. They should agree with the information on the front cover of this manual. If they do not, you can obtain the current version of the LANL POP2 manual at

The Manual revision letter and release date indicate corrections or additions to the manual corresponding to the stated version of the model.

If you obtained POP directly from LANL, technical support is provided by John Davis (, 505-667-4793) and Phil Jones ( , 505-667-6386). If you are using POP as a component of the NCAR Climate System Model (CCSM4), technical support is provided by NCAR (

We are always interested in learning about your experiences with POP, favorable or otherwise. Send your comments and suggestions for improvements to Bug reports should be sent to

CCSM4 Notes

The CCSM4 version of this manual, which you are now reading, is based on the LANL version but has been customized to include information about CCSM4-specific POP options. Important CCSM4 information has been noted throughout this guide: in the text, special subsections labeled "CCSM4 Notes" have been added and in tables, new CCSM4 columns appear.

Send CCSM4 POP2 bug reports to the CCSM4 helpdesk at

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