GEOS-Chem versions

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

Current GEOS-Chem version in development

Previously released GEOS-Chem versions

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. 09:45, 15 October 2009 (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.

File:Mean oh 1yr.png

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 but 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 upgrade protocol

We use the Unix Concurrent Versions System (CVS) to archive the GEOS–Chem code. We update the code incrementally; only a few changes are made from one version to the next.

1-month benchmarks

Each GEOS–Chem release is benchmarked with a 1-month standard benchmark simulation before it is released to the user community. The results of the 1-month benchmark are then compared to the results of the 1-month benchmark for the previous GEOS version. In this way, consistency between successive GEOS–Chem releases can be ensured. Prof. Daniel Jacob is currently responsible for examining the results of all GEOS–Chem 1-month benchmark simulations.

The 1-month benchmarks data files (source code, run directory, and output plots) may be downloaded from: 

ftp ftp.as.harvard.edu
cd pub/geos-chem/beta_releases
cd pub/geos-chem/public_releases

1-year benchmarks

Some GEOS-Chem versions (i.e. those versions which we have made major changes to the emissions, chemistry mechanism, etc.). For those versions we also perform a 1-year benchmark simulation, which allows us to test the output of the model against both monthly and seasonal observations from a wide variety of sources, including aircraft campaigns, ozonesondes, and various ground stations. Jennifer Logan is currently responsible for examining the results of GEOS-Chem 1-year benchmark simulations.

Data and plots from the 1-year benchmark simulations may be downloaded from: 

ftp ftp.as.harvard.edu
cd pub/geos-chem/1yr_benchmarks

--Bob Y. 15:59, 24 February 2010 (EST)

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