GEOS-Chem versions

Here we have posted links to a separate wiki page describing each GEOS-Chem model version.

Current GEOS-Chem version(s) in development

Version	Expected Release	Important features	Benchmark history
GEOS-Chem v9-01-03	TBA 2012	Updates to std chem mechanism from JPL; Updated dicarbonyls simulation; SOA simulation with semi-volatile POA; Updated acetone sources & sinks; POPs mechanism; Bromine chemistry mechanism	v9-01-03 history

--Bob Y. 14:30, 2 August 2011 (EDT)

Previously released GEOS-Chem versions

Version	Type	Date Released	Important features	Benchmark history
GEOS-Chem v9-01-02	-	28 Nov 2011	APM aerosol microphysics; GFED3 biomass emissions; RETRO Anthropogenic Emissions; Various fixes to correct several identified issues	v9-01-02 history
GEOS-Chem v9-01-01	public	10 Feb 2011 07 Jun 2011 (re-release)	Compatibility with the GMAO MERRA met data product; Updated lightning NOx; various fixes	v9-01-01 history
GEOS-Chem v8-03-02	beta	07 Sep 2010	Updated Hg and CO2 simulations
GEOS-Chem v8-03-01	public	04 May 2010	ISORROPIA II; TOMAS microphysics option; Updates to SOA and photolysis
GEOS-Chem v8-02-04	beta	24 Feb 2010	LINOZ strat chemistry; NEI2005 anthro emissions; MEGAN v2.1 biogenic emissions
GEOS-Chem v8-02-03	beta	Oct 2009	KPP solver; ICOADS emissions; Updated makefile structure
GEOS-Chem v8-02-02	beta	08 Jun 2009	Non-local PBL mixing scheme; Updated Bond BC & OC emissions
GEOS-Chem v8-02-01	public	26 May 2009	Updated chemistry & photolysis reactions; Glyoxal chemistry mechanism
GEOS-Chem v8-01-04	beta	10 Mar 2009	Various emissions updates (regional & global inventories); GFED2 biomass emissions updates
GEOS-Chem v8-01-03	beta	Dec 2008	Installation of GMI TPCORE routine
GEOS-Chem v8-01-02	beta	Nov 2008	Nested grid simulations for 0.5° x 0.666°
GEOS-Chem v8-01-01	public	May 2008	Capability to run with GEOS-5 met fields
GEOS-Chem v7-04-13	beta	Nov 2007	H2/HD simulation; Bug fixes in SMVGEAR, lightning, and dynamic tropopause
GEOS-Chem v7-04-12	beta	Oct 2007	Introduction of dynamic tropopause

NOTES:

1. Information about 1-year benchmark simulations can be found on the individual wiki pages for each GEOS-Chem version listed above.
2. For versions prior to v7-04-12, please see the GEOS-Chem version history web page.

--Bob Y. 12:12, 15 July 2011 (EDT)

Mean OH from GEOS-Chem 1-year benchmark simulations

Here is a plot of the mean OH concentration from several recent GEOS–Chem 1-year benchmark simulations. The mean OH is an indicator how the chemistry mechanism is performing. Typical values are 10–11 x 10⁵ molecules cm^-1.

NOTES:

1. Runs done with GEOS-3 met are denoted by squares; GEOS-4 met: triangles; GEOS-5 met: circles.
2. The large jump in mean OH between v8-01-04-Run2 and v8-02-01-Run0 is likely attributed to the photolysis rate updates for ketones and aldehydes. See this document about the new photolysis mechanism. However, we are still investigating this.
3. The runs done with GEOS-4 met have higher mean OH than the GEOS-3 and GEOS-5 runs because of the missing high cloud optical depth in the GEOS-4 met fields.
4. The large jump upward from v7-04-12-Run1 to v7-04-12-Run2 is attributed to a major upgrade of the lightning NOx algorithm. v7-04-12 was the first GEOS-Chem version to redistribute flashes regionally according to OTD/LIS statistics.
5. v7-04-13 uses the same lightning algorithm as in v7-04-12-Run2. However, the lightning flash redistribution according to OTD/LIS statistics was switched from regional to local redistribution.
6. v7-04-02-Run0 and v7-04-02-Run1 used GEIA biogenic emissions. v7-04-02-Run2 swiched to MEGAN biogenic emissions.
7. v8-02-04-Run0 used the new MEGAN v2.1 biogenic emissions with the old AVHRR-derived LAI product. This caused the mean OH to be much lower than runs v8-02-04-Run1 and v8-02-04-Run2, which used the newer MODIS LAI product. See the full discussion HERE.

--Bob Y. 16:21, 24 February 2010 (EST)

GEOS–Chem Benchmarking Procedure

GEOS-Chem Benchmarking Protocol
adopted at the 5th International GEOS-Chem Meeting (May 2011)

1. Any change to the GEOS–Chem source code will require a dedicated 1-month "full-chemistry" benchmark and a version update code a,b,c... (such as v9–01–02a). These final letter codes are for internal use only and do not represent a version release. The benchmark results will be posted publicly with an email sent to the GEOS–Chem Steering Committee.

2. The developer will assess the benchmark results by filling out a form (created by Colette Heald and adapted to a wiki page) for all to see. If the developer has any concerns about the benchmark results they will contact the GEOS-Chem Support Team, the relevant GEOS–Chem Working Group Chairs, or Model Scientist Daniel Jacob. GEOS–Chem Steering Committee members can also comment on the benchmark results if they desire.

3. Once the developer is satisfied, GEOS–Chem Model Scientist Daniel Jacob will quickly review the results and approve the new internal version.

4. 1-year benchmarks for these internal version updates will be conducted only if justifiably requested by the developer or by GEOS–Chem Steering Committee members.

5. Each new version release (such as v9–01–02) will be subject to a 1-year benchmark to be inspected by the GEOS–Chem Steering Committee before approval (as was done for v9–01–01). Changes will be bundled so that we will have new versions released only every 4 months or so — this has been our rhythm in recent years.

Also, for each new version, we shall perform a standard 1-year Rn-Pb-Be simulation. This type of simulation is useful in examining if there are any significant impacts in convection or wet scavenging.

For more information about the standard 1-month and 1-year benchmark simulations, please see our GEOS-Chem Benchmarking web page.

--Bob Y. 10:31, 3 August 2011 (EDT)