Scientific and Technical Documentation for Parameterizations in the Common Community Physics Package (CCPP)

The scientific and technical documentation of the model physics should track all aspects of the parameterizations. Successful documentation will make information easily accessible, facilitate stakeholder communication and help cut support costs. As part of its effort to set up a framework for the Common Community Physics Package (CCPP), the Global Model Test Bed (GMTB) of the Developmental Testbed Center (DTC) has documented the 2017 operational Global Forecast System (GFS) physics suite using the “Doxygen” software. The documentation has been embedded within the Fortran code, which makes it relatively straight-forward to maintain as new developments are added to the model. Since the CCPP is distributed through a Git repository on Github, which has a functionality to track changes made to each model component, the evolution of the model physics can also be documented.

Comprehensive documentation will be required of advanced physics schemes before they can be included in the CCPP. Part of this documentation, namely subroutine argument tables, has functional significance. Variables must be described in a particular format so they can be parsed by Python scripts that “automatically” generate a software cap for a given physics scheme. The purpose of this poster is to provide an understanding of how to properly document a physics scheme for the CCPP using Doxygen in-line comments. It covers the scope of the scientific and technical information that should be in the documentation, and how to mark up the in-line comments so that Doxygen will parse them correctly to generate html files that can be displayed online.