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GEOS–Chem Wiki

GEOS-Chem Community Mission: to advance understanding of human and natural influences on the environment through a comprehensive, state-of-the-science, readily accessible global model of atmospheric composition. The GEOS–Chem model is a global 3-D model of atmospheric composition driven by assimilated meteorological observations from the Goddard Earth Observing System (GEOS) of the NASA Global Modeling and Assimilation Office. It is applied by research groups around the world to a wide range of atmospheric composition problems, Central management and support of the model is provided by the Atmospheric Chemistry Modeling Group at Harvard University. This wiki is meant to facilitate communication between GEOS-Chem users and developers. If this is your first time here, check out the features page. If you would like to contribute to the wiki, please register as a user by clicking create account at the top right corner of this page. New information is continually being added to the wiki, so please check back here often, or even better, subscribe to the recent changes' RSS feed: you will not miss a discussion!

Getting started w/ GEOS-Chem:	Welcome letter for new users	GEOS-Chem basics
Current public release:	GEOS-Chem v11-01	v11-01 benchmark history
Version in development:	GEOS-Chem v11-02	v11-02 benchmark history
Version for HPC environments:	GEOS-Chem HP	GEOS-Chem HP Status
List of publications:	Refer to this page
GEOS-Chem public license:	License agreement document	List of developers

General information about GEOS-Chem
Introduction to GEOS-Chem and the International GEOS-Chem User Community
Overview of GEOS-Chem and its user community GEOS-Chem People & Projects GEOS-Chem Support Team GEOS-Chem newsletters Recommendations for offering co-authorships to GEOS-Chem developers GEOS-Chem code development history Narrative description of GEOS-Chem Basic information about getting set up with GEOS-Chem GEOS-Chem welcome letter for new users Features of the GEOS-Chem public wiki Customizing your GEOS-Chem Wiki Settings GEOS-Chem Search Engines	GEOS-Chem Steering Committee GEOS-Chem model development priorities GEOS-Chem Working Groups Adjoint Model and Data Assimilation Working Group Aerosols Working Group Carbon Cycle Working Group Chemistry-Ecosystems-Climate Working Group GEOS-Chem High Performance Working Group Hg and POPs Working Group Chemistry Working Group Emissions and Deposition Working Group Transport Working Group GEOS-Chem Nested Model
Getting started with GEOS-Chem
GEOS-Chem basics (e.g. tutorials, user guides, etc.) Frequently asked questions about GEOS-Chem Minimum system requirements for GEOS-Chem Downloading GEOS-Chem source code and data GEOS-Chem performance Creating GEOS-Chem run directories GEOS-Chem coding style guide GEOS-Chem horizontal grids and vertical grids	Initial conditions for GEOS-Chem Centralized chemistry time step Tips on how to debug GEOS-Chem effectively Parallelizing GEOS-Chem with the OpenMP directives Common GEOS-Chem error messages Adding tracers to GEOS-Chem (v10-01 and prior) Adding species to GEOS-Chem (v11-01 and later) Adding passive species to GEOS-Chem

GEOS-Chem Code Developers' Forums
Coding	Meteorological Fields
Software development GEOS-Chem versions under development Version control with Git GEOS-Chem coding and debugging GEOS-Chem coding style guide List of GEOS-Chem bugs and in which version they were resolved Currently unresolved issues in GEOS-Chem Known GEOS-Chem issues caused by compiler bugs Machine issues and portability Debugging with the GEOS-Chem unit tester Performing Difference Tests with GEOS-Chem Common GEOS-Chem error messages Reporting GEOS-Chem bugs to the GCST GEOS-Chem performance Profiling GEOS-Chem Passing array arguments efficiently in GEOS-Chem Floating point math issues Results from 7-day timing tests	Overview of GMAO met data products Version history of GMAO met data products Available met data for nested grid simulations List of reprocessed met fields GMAO MERRA-2 List of MERRA-2 met fields used by GEOS-Chem Implementing MERRA-2 into GEOS-Chem GMAO GEOS-FP List of GEOS-FP met fields used by GEOS-Chem Implementing GEOS-FP into GEOS-Chem GMAO MERRA "reanalysis" List of MERRA met fields used by GEOS-Chem Implementing MERRA into GEOS-Chem GMAO GEOS-5.2.0 List of GEOS-5.2.0 met fields used by GEOS-Chem Issues with GEOS-5.2.0 met data
Emissions	Chemistry
HEMCO emissions component HEMCO data directories The HEMCO User's Guide Implementation of HEMCO in GEOS-Chem Emissions categories Aerosol emissions Aircraft emissions Anthropogenic emissions Scale factors for anthropogenic emissions Biofuel emissions Biogenic emissions Biomass burning emissions Lightning NOx emissions Ship emissions Soil NOx emissions Volcanic emissions Historical and future emissions	GEOS-Chem chemistry mechanisms Stratopsheric chemistry options Specialty simulations (aka "offline simulations") Photolysis mechanisms used in GEOS-Chem Species in GEOS-Chem GEOS-Chem species database Physical properties of GEOS-Chem species GEOS-Chem species units Species indexing in GEOS-Chem Other resources FlexChem Chemistry Issues Process Analysis Diagnostics Linking GEOS-Chem to CMAQ Coupling GEOS-Chem with RRTMG DSMACC chemical box model
Dynamics	Deposition
Advection scheme TPCORE Boundary layer mixing Cloud convection Dynamic tropopause	Dry deposition Leaf area indices in GEOS-Chem Olson land map Wet deposition
Aerosols	Benchmarking and Evaluation
Aerosol-only simulation Aerosol optical properties Aerosol thermodynamical equilibrium Carbonaceous aerosols Mineral dust aerosols Secondary organic aerosols Sea salt aerosols Sulfate aerosols Aerosol Microphysics APM TOMAS	General info about GEOS-Chem benchmark simulations List of GEOS-Chem 1-year benchmark simulations Mean OH concentration GEOS-Chem v11-01 benchmark history GEOS-Chem v10-01 benchmark history GEOS-Chem v9-02 benchmark history FTP site with output from 1-year GEOS-Chem benchmark simulations Other resources GEOS-Chem participation in community intercomparisons Satellite Instrument Specifications Table
Nested grid simulations	Diagnostics
GEOS-Chem nested grid simulations Setting up GEOS-Chem nested grid simulations Available met data for nested grid simulations Protocol for nested-grid data downloads Steps to setup new nested domains GEOS-Chem nested model publications	List of current GEOS-Chem diagnostics Archiving diagnostics from HEMCO to netCDF files Diagnostic time step Mass Flux (ND24/25/26) Additional diagnostics
Related projects	Other resources
GEOS-Chem HP GEOS-Chem Adjoint GEOS-Chem Near-Real-Time Simulations FlexAOD ATom Field Campaign	GEOS-Chem publications page on ResearcherID IGC8 Meeting (May 2017) web site Presentations from the IGC7 meeting (2015) Presentations from the IGC6 meeting (2013)

Reference Section
IDL	GAMAP
Using IDL (Harris Geospatial Solutions site) Structures in IDL Pointers in IDL Overview of Mathematics in IDL IDL Astronomy User's Library JHU/APL/S1R IDL routines page Craig Markwardt's IDL library Reading binary files in IDL	GAMAP web page GAMAP on-line users' guide GAMAP bugs and fixes GAMAP tips and tricks General GAMAP usage TVMAP cheat sheet File I/O with GAMAP Working with timeseries output in GAMAP Color and graphics with GAMAP Loading Color Tables in GAMAP v2.12 Working with color in IDL by Chris Holmes Regridding with GAMAP Date and time computations with GAMAP Text manipulation with GAMAP
Fortran	Perl
Intel Fortran Compiler Version 11.1 Version 12.1 Version XE 13.1 Version 15.0 Version 17 PGI Fortran compiler User Guide Reference Guide GNU Fortran compiler Fortran tutorials	Perl.com Beginning Perl by Simon Cozens (free online book) Perl in 20 pages MediaWiki User's Guide Comprehensive Perl Archive Network (CPAN.org)
R	Python
The R project for statistical computing The R journal R by example Using R to analyze GEOS-Chem data	Python code for GEOS-Chem Python.org: Main site for all things Python Python.org Tutorial PythonWiki.org: List of tutorials and resources Google's Python tutorial
NCAR Command Language (NCL)	Wiki documentation
NCL main page NCL applications NCL documentation Sign up for NCL-Talk email list NCL4GC: NCL tools for GEOS-Chem	Sandbox MediaWiki FAQ MediaWiki User's Guide Examples of Wiki markup text One-page editing reference card Configuration Settings list MediaWiki release mailing list