GEOS-Chem Newsletter August 2009

From Geos-chem
Jump to: navigation, search

Dear GEOS-Chem Users,

Here is the August 2009 GEOS-Chem Newsletter.

Thank you for your continued support of GEOS-Chem!

Bob Yantosca, Philippe Le Sager, and Claire Carouge

GEOS-Chem Update

Randall Martin named GEOS-Chem Co-Model Scientist

Randall Martin has been named "GEOS-Chem Co-Model Scientist" by Daniel Jacob and the GEOS-Chem Steering Committee. Randall has been involved with GEOS-Chem model develompent almost since the beginning. Both he and his research group at Dalhousie have made important contributions to the standard GEOS-Chem model in the areas of emissions inventories, inverse modeling, regional modeling, and satellite retrievals/data analysis. Please join us in congratulating Randall on this appointment!

GEOS-Chem Steering Committee

The next GEOS-Chem Steering Committee Telecon will take place on September 10, 2009 @ 10:30 AM ET. If you have anything that you would like to bring to the Steering Committee's attention, please contact your Working Group chairperson.

GEOS-Chem Working Groups

We ask that each GEOS-Chem user join the Working Group that is most relevant to his/her area of research. For more information about a particular working group, please contact the appropriate Working Group Chairperson(s).

The Working Group Wiki pages are constantly being updated! Please be sure to check them often for the latest news:

GEOS-Chem v8-02-03

The next "beta" release will be GEOS-Chem v8-02-03. This version will have the following updates:

  • Kpp chemical solver (Adrian Sandu group @ VT)
  • ICOADS ship emissions (Chulkyu Lee @ Dalhousie)
  • Diagnostic updates (Claire Carouge & Philippe Le Sager)
  • Use of GEOS-5 ozone columns (C. Carouge)

The version is currently beta-testing. A new version of the Kpp solver package was provided to us recently by VT. Some work still needs to be done in order to interface this into GEOS-Chem. Stay tuned...

New plot of GEOS-Chem Mean OH on website

We have replaced the existing plot of mean OH concentrations from past GEOS-Chem 1-month benchmarks with a plot of mean OH concentrations from several recent 1-year benchmarks. This is a much more accurate representation of how the GEOS-Chem full-chemistry simulation is performing than the previous plot.

GEOS-Chem Nested Grid Simulations

Protocol for Obtaining Met Data

The Harvard group maintains an archive of GEOS meteorological data available to the GEOS-Chem community for ftp download. It includes standard operational GEOS data at 2° x 2.5° and 4° x 5° resolution, plus some special and nested products. There is increasing demand in the GEOS-Chem community for custom data sets of native-resolution (presently 0.5° x 0.667°) or special GEOS meteorological data. In the spirit of maintaining the successful grass-roots community approach of GEOS-Chem, users who do not find what they need in the Harvard archive should take it upon themselves to download and archive the GEOS data that they need, and then make these data available to the GEOS-Chem community.

For more information, please see this document about the GEOS-Chem data download protocol.

Current Data Availability

We now have set up a new wiki page which lists the available met data for nested-grid simulations. Please check this page frequently for the latest updates.

GEOS-Chem user groups who plan on obtaining nested grid data on their own are asked to update the wiki page before downloading data. This will help to coordinate data downloading efforts among user groups.

Nested Grid Geographic Regions

We currently have two defined geographic nested grid regions:

There has been some interest in creating nested grid simulations for other geographic regions, most notably Europe. We encourage those of you who are interested in alternate nested grid regions to join the Regional Air Quality Working Group, which is co-chaired by Rokjin Park and Yuxuan Wang.

Required Code Modifications

Yuxuan Wang has created a checklist of updates that have to be made in the GEOS-Chem source code for the North American Nested Grid 0.5° x 0.667° simulation. This can also be used as a guide for those who are planning to develop GEOS-Chem nested grid simulations for other geographical regions.

GEOS-5 met field reprocessing

Global and China Nested Grid

The GEOS-5 reprocessing for 2004-present has now been completed. You should obtain the newly reprocessed data if you have not yet done so.

You may download the data from:

 Nested China
 cd pub/geos-chem/data/GEOS_0.5x0.666_CH.d/GEOS_5/YYYY/MM/

 2 x 2.5 Global
 cd pub/geos-chem/data/GEOS_2x2.5.d/GEOS_5/YYYY/MM/

 4 x 5 Global
 cd pub/geos-chem/data/GEOS_4x5.d/GEOS_5/YYYY/MM/

where YYYY/MM/ are the year and month of data that you wish to download.

Updated OTD/LIS redistribution factors for lightning

Lee Murray has regenerated the OTD/LIS local redistribution factors for use with the new reprocessed GEOS-5 met data fields. The scale factors were based on GEOS-5 met data from Dec 2003 through Feb 2009.

You may obtain the new OTD/LIS scale factors from:

cd pub/geos-chem/data/GEOS_4x5/lightning_NOx_200907
mget *
cd pub/geos-chem/data/GEOS_2x2.5/lightning_NOx_200907
mget *
cd pub/geos-chem/data/GEOS_0.5x0.666_CH/lightning_NOx_200907
mget *

The OTD/LIS files are named with the following convention:


Note that the version of the data has been updated from v3 to v4, in order to distinguish them from the files in the previous directory lightning_NOx_200709/.

NOTE: The GEOS-4 files in lightning_NOx_200907/ are identical to those in lightning_NOx_200709/. For consistency and simplicity of coding, they have been renamed from v3 to v4.

You will also need to get an updated version of source code file lightning_nox_mod.f, which has been modified to read in hese new OTD/LIS local factors. You may obtain this from:

cd pub/geos-chem/patches/v8-02-02

NOTE: If you are compiling GEOS-Chem for GEOS-5 meteorology, you must also uncomment the following switch


in the define.h header file. However, at a later time the IN_CLOUD_OD switch will be removed from the code. We will keep it for now in case some GEOS-Chem users may not have all of the GEOS-5 met data downloaded onto their systems.

NOTE: IN_CLOUD_OD only needs to be defined for GEOS-5 meteorology.

ESMF and Column Code Update

Rapid progress continues to be made in the creation of the GEOS-Chem column code. All of the GEOS-Chem processes excluding transport (dry deposition, wet deposition, PBL Mixing, cloud convection, gas-phase chemistry, aerosol chemistry) have now been columnized.

We are also starting to rewrite the emissions routines in order to be compatible with the column code. In particular, disk I/O must be separated out from the places in the code where computations are done.

You can track our progress on the GEOS-Chem column code wiki page. Check back often for the latest developments!


netCDF and HDF Utility Codes

Several of you have asked us recently if there are any Fortran codes to read data from netCDF, HDF, or HDF-EOS format files. The answer is yes! Bob Yantosca has recently repackaged his NcdfUtilities and Hdf4Utilities packages and has improved the documentation. You may download these from:

cd pub/geos-chem/downloads
get NcdfUtilities.tar.gz
get Hdf4Utilities.tar.gz

In each of these packages there is a detailed README which guides you through the process of building the code. You can also generate detailed reference manuals for these packages in *.pdf and *.ps formats.

Vacation Schedule

Philippe is currently on vacation (scheduled to return on August 10th). Bob Y. will be on vacation in late August/early September around Labor Day (dates TBD). Please plan accordingly.

--Bob Y. 10:28, 7 August 2009 (EDT)