Downloading GEOS-Chem data directories

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Previous | Next | Getting Started with GEOS-Chem

  1. Minimum system requirements
  2. Downloading source code
  3. Downloading data directories
  4. Creating run directories
  5. Configuring runs
  6. Compiling
  7. Running
  8. Output files
  9. Visualizing and processing output
  10. Coding and debugging
  11. Further reading


This page describes where you can obtain the GEOS-Chem source code and required data files.

Overview

In addition to the files contained in the run directories, GEOS-Chem also needs to access data directories containing:

  • Meteorological data (a.k.a. the "met fields) used to drive GEOS–Chem
  • Emissions inventories used by GEOS-Chem
  • Scale factors used to scale emissions from a base year to a given year
  • Sample restart files that you can use to spin up your GEOS-Chem simulations
  • Oxidant (OH, O3) concentrations for both full-chemistry and offline simulations
  • IPCC future scenarios (for GCAP simulations)
  • Other GEOS–Chem specific data files.

These files are often too large to store in a single user's disk space. Therefore, they are meant to be stored in shared disk space where all GEOS-Chem users in your group can have access to them.

The GEOS-Chem shared data directories can be downloaded from archives at Harvard University and Dalhousie University. Unlike the source code and run directories, the data directory download can be done either by anonymous FTP or by the freely-available GNU wget utility. (We recommend wget because it is much more flexible and can be used to download several directories recursively.)

NOTE: If you are using GEOS-Chem on the Amazon Web Services cloud computing platform, then you can access the GEOS-Chem shared data directories as an S3 bucket (s3://gcgrid). Please see our cloud computing tutorial (cloud.geos-chem.org) for more details.

This page describes how you can download the GEOS-Chem shared data directories. Please also be sure to view the following pages for additional information:

--Bob Yantosca (talk) 15:17, 14 June 2019 (UTC)

Shared data directory archives

There are currently three data archives from which you may download the GEOS–Chem shared data directories:

Name Location Notes
Harvard ftp site ftp.as.harvard.edu Recommended for emissions data
  • Emissions data for HEMCO and non-emissions data for GEOS-Chem chemistry modules are frequently processed at Harvard University. Therefore, we recommend downloading those data from the Harvard archive.
Amazon Web Services S3 storage s3://gcgrid
  • This is an AWS S3 bucket containing a mirror of the Harvard University storage server (ftp.as.harvard.edu).
  • See our cloud computing tutorial (cloud.geos-chem.org) for more information.
  • NOTE: Downloading data from the cloud to your local server will incur an egress fee.
Dalhousie ftp site rain.ucis.dal.ca Recommended for met fields
  • GEOS-Chem met fields are currently processed at Dalhousie University. The Dalhousie archive, as a result, includes met fields for more recent dates than the Harvard archive. In addition, Dalhousie archive data files for the various nested grids that may not available be on the Harvard archive.
Compute Canada http://geoschemdata.computecanada.ca For 0.5° x 0.625° global MERRA-2 met fields and 0.25° x 0.3125° global GEOS-FP met fields

Harvard data directory archive

You can access the primary GEOS-Chem data download site via anonymous FTP at: 

ftp ftp.as.harvard.edu

We recommend that you use the wget utility to download these directories instead of anonymous FTP. Wget allows you to download multiple directories at once, with a command such as this one: 

wget -r -nH --cut-dirs=4 "http://ftp.as.harvard.edu/DIRECTORY_NAME"

See the tables below for the DIRECTORY_NAME options.

Directories for met fields and emissions data

If you are downloading the GEOS-FP or MERRA-2 met data, then please note the following:

  1. You will need to download the "CN" (constant) data files for each horizontal grid that you are using.
    • For GEOS-FP these are timestamped for 2011/01/01 and are found in these data directories of ftp.as.harvard.edu:
      • gcgrid/data/GEOS_4x5/GEOS_FP/2011/01/GEOSFP.20110101.CN.4x5.nc
      • gcgrid/data/GEOS_2x2.5/GEOS_FP/2011/01/GEOSFP.20110101.CN.2x25.nc
      • gcgrid/data/GEOS_0.25x0.3125_CH/GEOS_FP/2011/01/GEOSFP.20110101.CN.025x03125.CH.nc
      • gcgrid/data/GEOS_0.25x0.3125_NA/GEOS_FP/2011/01/GEOSFP.20110101.CN.025x03125.NA.nc
    • For MERRA-2 these are timestamped for 2015/01/01 and are found in these data directories of ftp.as.harvard.edu:
      • gcgrid/data/GEOS_4x5/MERRA2/2015/01/MERRA2.20150101.CN.4x5.nc4
      • gcgrid/data/GEOS_2x2.5/MERRA2/2015/01/MERRA2.20150101.CN.2x25.nc4
      • gcgrid/data/GEOS_0.5x0.625_AS/MERRA2/2015/01/MERRA2.20150101.CN.05x0625.AS.nc4
      • gcgrid/data/GEOS_0.5x0.625_NA/MERRA2/2015/01/MERRA2.20150101.CN.05x0625.NA.nc4

Additional notes:

  • Prior to downloading GEOS-FP data, please be aware of caveats regarding use of GEOS-FP. See the GEOS-FP wiki page for more information.
  • NASA/GMAO recommends to discontinue use of the GEOS-5 and MERRA met field data products, as these have now been superseded by GEOS-FP and MERRA-2.

The path gcgrid/data/ExtData/ is the root path under which the GEOS–Chem shared data directories reside. This is where you will find the GEOS-Chem met fields and emissions data.

Starting with GEOS-Chem v10-01, the data directory naming structure has changed since we no longer need to store emissions data on multiple grids. All of the GEOS-Chem data directories are now subdirectories of the ExtData directory. For more information, please see our Setting up the ExtData directory wiki page.

Directory Description
gcgrid/data/ExtData/ Root Data Directory
gcgrid/data/ExtData/CHEM_INPUTS/ Contains non-emissions data for GEOS-Chem chemistry modules
gcgrid/data/ExtData/HEMCO/ Contains emissions data for the HEMCO emissions component
0.25° x 0.3125° Data Directories Description
gcgrid/data/ExtData/GEOS_0.25x0.3125_CH/GEOS_FP/YYYY/MM/ GEOS-FP met fields for 0.25° x 0.3125° CH nested grid simulations
gcgrid/data/ExtData/GEOS_0.25x0.3125_NA/GEOS_FP/YYYY/MM/ GEOS-FP met fields for 0.25° x 0.3125° NA nested grid simulations
0.5° x 0.625° Data Directories Description
gcgrid/data/ExtData/GEOS_0.5x0.625_AS/MERRA2/YYYY/MM/ MERRA-2 met fields for 0.5° x 0.625° AS nested grid simulations
gcgrid/data/ExtData/GEOS_0.5x0.625_NA/MERRA2/YYYY/MM/ MERRA-2 met fields for 0.5° x 0.625° NA nested grid simulations
2° x 2.5° Data Directories Description
gcgrid/data/ExtData/GEOS_2x2.5/GEOS_FP/YYYY/MM GEOS-FP met data for 2° x 2.5° global simulations
gcgrid/data/ExtData/GEOS_2x2.5/MERRA2/YYYY/MM MERRA-2 met fields for 2° x 2.5° global simulations
4° x 5° Data Directories Description
gcgrid/data/ExtData/GEOS_4x5/GEOS_FP/YYYY/MM/ GEOS-FP met fields for 4° x 5° global simulations
gcgrid/data/ExtData/GEOS_4x5/MERRA2/YYYY/MM/ MERRA-2 met fields for 4° x 5° global simulations

--Melissa Sulprizio (talk) 18:26, 29 August 2018 (UTC)

Directories for 1-month and 1-year benchmarks

You can find output files and evaluation plots for 1-month and 1-year benchmark simulations in the following directories:

Directory Description
gcgrid/geos-chem/1mo_benchmarks/ Contains the following types of data from the 1-month benchmark simulations that are used to evaluate GEOS-Chem:
  • Restart files
  • Model output (bpch and netCDF formats)
  • Log files
  • Input files
  • Evaluation plots
gcgrid/geos-chem/1yr_benchmarks/ Contains the following types of data from the 1-year benchmarks used to evaluate GEOS-Chem:
  • Restart files
  • Model output (bpch and netCDF formats)
  • Log files
  • Input files
  • Evaluation plots

--Bob Yantosca (talk) 21:46, 19 December 2016 (UTC)

Amazon Web Services S3 storage

The Harvard data directory archive is mirrored as an Amazon Web Services S3 directory. You can get a directory listing with this command: 

aws s3 ls --request-payer=requester s3://gcgrid/...

and you can copy data to your Elastic Block Storage 

aws s3 cp --request-payer=requester s3:/gcgrid/DIRECTORY-NAME

For more information, please see:

  1. Our GEOS-Chem cloud computing tutorial cloud.geos-chem.org
  2. aws s3 ls command reference
  3. aws s3 cp command reference
  4. More AWS S3 examples

--Bob Yantosca (talk) 14:31, 3 October 2019 (UTC) Fopr mo

Dalhousie data directory archive

The GEOS-Chem data and meteorological fields used by Dalhousie University are also available via anonymous FTP from: 

ftp rain.ucis.dal.ca

We recommend that you use the wget utility to download these directories instead of anonymous FTP. Wget allows you to download multiple directories at once. The Wget command will take the form: 

wget -r -nH --cut-dirs=4 "ftp://rain.ucis.dal.ca/DIRECTORY_NAME"

See the table below for the DIRECTORY_NAME options.

Dalhousie directory structure

If you are downloading the GEOS-FP or MERRA-2 met data, then please note the following:

  1. You will need to download the "CN" (constant) data files for each horizontal grid that you are using.
    • For GEOS-FP these are timestamped for 2011/01/01 and are found in these data directories of rain.ucis.dal.ca:
      • ctm/GEOS_4x5.d/GEOS_FP/2011/01/GEOSFP.20110101.CN.4x5.nc
      • ctm/GEOS_2x2.5.d/GEOS_FP/2011/01/GEOSFP.20110101.CN.2x25.nc
      • ctm/GEOS_0.25x0.3125_CH.d/GEOS_FP/2011/01/GEOSFP.20110101.CN.025x03125.CH.nc
      • ctm/GEOS_0.25x0.3125_EU.d/GEOS_FP/2011/01/GEOSFP.20110101.CN.025x03125.EU.nc
      • ctm/GEOS_0.25x0.3125_NA.d/GEOS_FP/2011/01/GEOSFP.20110101.CN.025x03125.NA.nc
    • For MERRA-2 these are timestamped for 2015/01/01 and are found in these data directories of rain.ucis.dal.ca:
      • ctm/GEOS_4x5.d/MERRA2/2015/01/MERRA2.20150101.CN.4x5.nc4
      • ctm/GEOS_2x2.5.d/MERRA2/2015/01/MERRA2.20150101.CN.2x25.nc4
      • ctm/GEOS_0.5x0.625_AS.d/MERRA2/2015/01/MERRA2.20150101.CN.05x0625.AS.nc4
      • ctm/GEOS_0.5x0.625_EU.d/MERRA2/2015/01/MERRA2.20150101.CN.05x0625.EU.nc4
      • ctm/GEOS_0.5x0.625_NA.d/MERRA2/2015/01/MERRA2.20150101.CN.05x0625.NA.nc4


Additional notes:

  • Prior to downloading GEOS-FP data, please be aware of caveats regarding use of GEOS-FP. See the GEOS-FP wiki page for more information.
  • Global MERRA-2 data at 0.5° x 0.625° resolution and GEOS-FP data at 0.25° x 0.3125° resolution have been moved to the Compute Canada data directory archive.
Directory Description
ctm/ExtData/ Root Data Directory
ctm/CHEM_INPUTS/ Contains non-emissions data for GEOS-Chem chemistry modules
ctm/ExtData/HEMCO/ Contains emissions data for the HEMCO emissions component
0.25° x 0.3125° Data Directories Description
ctm/GEOS_0.25x0.3125_CH.d/GEOS_FP/YYYY/MM GEOS-FP met fields for 0.25° x 0.3125° CH nested grid simulations
ctm/GEOS_0.25x0.3125_EU.d/GEOS_FP/YYYY/MM GEOS-FP met fields for 0.25° x 0.3125° EU nested grid simulations
ctm/GEOS_0.25x0.3125_NA.d/GEOS_FP/YYYY/MM GEOS-FP met fields for 0.25° x 0.3125° NA nested grid simulations
0.5° x 0.666° Data Directories Description
ctm/GEOS_0.5x0.666_CH.d/GEOS_5/YYYY/MM GEOS-5 met field files for 0.5° x 666° CH nested grid simulations
ctm/GEOS_0.5x0.666_EU.d/GEOS_5/YYYY/MM GEOS-5 met field files for 0.5° x 666° EU nested grid simulations
ctm/GEOS_0.5x0.666_NA.d/GEOS_5/YYYY/MM GEOS-5 met field files for 0.5° x 666° NA nested grid simulations
0.5° x 0.625° Data Directories Description
ctm/GEOS_5x0.625_AS.d/MERRA2/YYYY/MM MERRA-2 met fields for 0.5° x 0.625° AS nested grid simulations
ctm/GEOS_5x0.625_EU.d/MERRA2/YYYY/MM MERRA-2 met fields for 0.5° x 0.625° EU nested grid simulations
ctm/GEOS_5x0.625_NA.d/MERRA2/YYYY/MM MERRA-2 met fields for 0.5° x 0.625° NA nested grid simulations
2° x 2.5° Data Directories Description
ctm/GEOS_2x2.5.d/GEOS_4_v4/YYYY/MM/ GEOS-4 met fields for 2° x 2.5° global simulations
ctm/GEOS_2x2.5.d/GEOS_5/YYYY/MM GEOS-5 met fields for 2° x 2.5° global simulations
ctm/GEOS_2x2.5.d/GEOS_FP/YYYY/MM GEOS-FP met fields for 2° x 2.5° global simulations
ctm/GEOS_2x2.5.d/MERRA/YYYY/MM MERRA met fields for 2° x 2.5° global simulations
ctm/GEOS_2x2.5.d/MERRA2/YYYY/MM MERRA-2 met fields for 2° x 2.5° global simulations
4° x 5° Data Directories Description
ctm/GEOS_4x5.d/GEOS_4_v4/YYYY/MM GEOS-4 met fields for 4° x 5° global simulations
ctm/GEOS_4x5.d/GEOS_5/YYYY/MM GEOS-5 met fields for 4° x 5° global simulations
ctm/GEOS_4x5.d/GEOS_FP/YYYY/MM GEOS-FP met fields for 4° x 5° global simulations
ctm/GEOS_4x5.d/MERRA/YYYY/MM MERRA met fields for 4° x 5° global simulations
ctm/GEOS_4x5.d/MERRA2/YYYY/MM MERRA-2 met fields for 4° x 5° global simulations

A catalog of available data may be found HERE.

--Melissa Sulprizio (talk) 14:22, 24 March 2017 (UTC)

Compute Canada data directory archive

A copy of the Dalhousie archive of global and nested met fields, as well as 0.5° x 0.625° global MERRA-2 data, 0.25° x 0.3125° global GEOS-FP data, and grid-independent emissions data are available from: 

http://geoschemdata.computecanada.ca

We recommend that you use the wget utility to download these directories. Wget allows you to download multiple directories at once. The Wget command will take the form: 

wget -r -nH --cut-dirs=2 "http://geoschemdata.computecanada.ca/DIRECTORY_NAME"

See the table below for the DIRECTORY_NAME options.

Compute Canada directory structure

If you are downloading the met data, then please note the following: You will need to download the "CN" (constant) data files for each horizontal grid that you are using.

    • For GEOS-FP these are timestamped for 2011/01/01 and are found in these data directories of geoschemdata.computecanada.ca:
      • GEOS_4x5.d/GEOS_FP/2011/01/GEOSFP.20110101.CN.4x5.nc
      • GEOS_2x2.5.d/GEOS_FP/2011/01/GEOSFP.20110101.CN.2x25.nc
      • GEOS_0.25x0.3125_CH.d/GEOS_FP/2011/01/GEOSFP.20110101.CN.025x03125.CH.nc
      • GEOS_0.25x0.3125_EU.d/GEOS_FP/2011/01/GEOSFP.20110101.CN.025x03125.EU.nc
      • GEOS_0.25x0.3125_NA.d/GEOS_FP/2011/01/GEOSFP.20110101.025x03125.NA.nc
      • GEOS_0.25x0.3125/GEOS_FP/2011/01/GEOSFP.20110101.CN.025x03125.nc
    • For MERRA-2 these are timestamped for 2015/01/01 and are found in these data directories of geoschemdata.computecanada.ca:
      • GEOS_4x5.d/MERRA2/2015/01/20150101.CN.4x5.nc4
      • GEOS_2x2.5.d/MERRA2/2015/01/20150101.CN.2x25.nc4
      • GEOS_0.5x0.625_AS.d/MERRA2/2015/01/MERRA2.20150101.CN.05x0625.AS.nc4
      • GEOS_0.5x0.625_EU.d/MERRA2/2015/01/MERRA2.20150101.CN.05x0625.EU.nc4
      • GEOS_0.5x0.625_NA.d/MERRA2/2015/01/MERRA2.20150101.CN.05x0625.NA.nc4
      • GEOS_0.5x0.625/MERRA2/2015/01/MERRA2.20150101.CN.05x0625.nc4
Directory Description
GEOS_0.25x0.3125/GEOS_FP/YYYY/MM GEOS-FP met fields for 0.25° 0.3125° global simulations
GEOS_0.5x0.625/MERRA2/YYYY/MM MERRA-2 met fields for 0.5° 0.625° global simulations
0.25° x 0.3125° Data Directories Description
GEOS_0.25x0.3125_CH.d/GEOS_FP/YYYY/MM GEOS-FP met fields for 0.25° x 0.3125° CH nested grid simulations
GEOS_0.25x0.3125_EU.d/GEOS_FP/YYYY/MM GEOS-FP met fields for 0.25° x 0.3125° EU nested grid simulations
GEOS_0.25x0.3125_NA.d/GEOS_FP/YYYY/MM GEOS-FP met fields for 0.25° x 0.3125° NA nested grid simulations
0.5° x 0.625° Data Directories Description
GEOS_0.5x0.625_AS.d/MERRA2/YYYY/MM MERRA-2 met fields for 0.5° x 0.625° AS nested grid simulations
GEOS_0.5x0.625_EU.d/MERRA2/YYYY/MM MERRA-2 met fields for 0.5° x 0.625° EU nested grid simulations
GEOS_0.5x0.625_NA.d/MERRA2/YYYY/MM MERRA-2 met fields for 0.5° x 0.625° NA nested grid simulations
2° x 2.5° Data Directories Description
GEOS_2x2.5.d/GEOS_4_v4/YYYY/MM/ GEOS-4 met fields for 2° x 2.5° global simulations
GEOS_2x2.5.d/GEOS_5/YYYY/MM GEOS-5 met fields for 2° x 2.5° global simulations
GEOS_2x2.5.d/GEOS_FP/YYYY/MM GEOS-FP met fields for 2° x 2.5° global simulations
GEOS_2x2.5.d/MERRA/YYYY/MM MERRA met fields for 2° x 2.5° global simulations
GEOS_2x2.5.d/MERRA2/YYYY/MM MERRA-2 met fields for 2° x 2.5° global simulations
4° x 5° Data Directories Description
GEOS_4x5.d/GEOS_4_v4/YYYY/MM GEOS-4 met fields for 4° x 5° global simulations
GEOS_4x5.d/GEOS_5/YYYY/MM GEOS-5 met fields for 4° x 5° global simulations
GEOS_4x5.d/GEOS_FP/YYYY/MM GEOS-FP met fields for 4° x 5° global simulations
GEOS_4x5.d/MERRA/YYYY/MM MERRA met fields for 4° x 5° global simulations
GEOS_4x5.d/MERRA2/YYYY/MM MERRA-2 met fields for 4° x 5° global simulations

--Melissa Sulprizio (talk) 14:22, 24 March 2017 (UTC)

Using wget to download the shared data directories

A simple way to download the GEOS-Chem emissions and met field data is to use the Unix wget utility. This allows you to download multiple files and directories at a time.

The wget utility is free and open-source (published by GNU), and comes standard with pretty much all builds of *nix (Linux, Ubuntu, Fedora, Centos, etc.). You can check out the user manual for more information.

NOTE: wget will not retrieve symbolically linked directories. To download directories that are symbolically linked, use wget with the paths that the symbolically linked directories point to. This may be necessary when setting up the ExtData directory if you are downloading data for the first time. See the Setting up the ExtData directory wiki page for more information.

Syntax

Most of the time, the syntax you will use to download multiple directories is as follows:

Downloading data from Harvard: 

wget -r -nH "http://ftp.as.harvard.edu/DIRECTORY_NAME/"

Downloading data from Dalhousie: 

wget -r -nH "ftp://rain.ucis.dal.ca/DIRECTORY_NAME/"

The options to wget are as follows: 

-r   Specifies recursive directory transfer (i.e. will download all subdirectories)
-nH  Will store all directories and subdirectories in DIRECTORY_NAME, not ftp.as.harvard.edu/DIRECTORY_NAME

If you wish to trim the name of the downloaded directory (i.e., so it downloads as DIRECTORY_NAME, not pub/geos-chem/data/DIRECTORY_NAME), then use the --cut-dirs option: 

wget -r -nH --cut-dirs=X "http://ftp.as.harvard.edu/DIRECTORY_NAME/"

where X is the number of directories to trim.

NOTE: The URL must be enclosed in quotes for file transfer to occur. If you omit the quotes then wget will just return a directory listing in a file named index.html without any files being downloaded.

Examples

1. Download all available GEOS-Chem 2° x 2.5° met field data files in the GEOS_2x2.5.d directory structure: 

wget -r -nH "http://ftp.as.harvard.edu/gcgrid/geos-chem/data/GEOS_2x2.5.d/" &

Due to the huge volume of data involved, this is not recommended, as the file downloads may swamp your system. It's better to do download the data smaller chunks. For example:

2. Download all GEOS-5 met data at 2° x 2.5° resolution: 

wget -r -nH "http://ftp.as.harvard.edu/gcgrid/geos-chem/data/GEOS_2x2.5.d/GEOS_5/" &

It may even be better to download one year at a time.:

3. Download all GEOS-5 met data at 2° x 2.5° resolution for 2008: 

wget -r -nH "http://ftp.as.harvard.edu/gcgrid/geos-chem/data/GEOS_2x2.5.d/GEOS_5/2008/" &

--Melissa Sulprizio 16:57, 8 April 2015 (EDT)

Obtain only updated files

Prasad Kasibhatla wrote:

Maybe this is common knowledge, but I just discovered that using the -N option in wget ensures that only files with newer timestamps than what resides on my local machines are downloaded - found this very useful to update my shared data directories.

--Melissa Payer 10:39, 1 June 2012 (EDT)

Downloading the shared data directories via anonymous FTP

You can also download the shared data directories via anonymous FTP: 

ftp ftp.as.harvard.edu
cd gcgrid/geos-chem/data/ExtData/GCAP_4x5
cd gcgrid/geos-chem/data/ExtData/GEOS_0.25x0.3125_CH
cd gcgrid/geos-chem/data/ExtData/GEOS_0.25x0.3125_NA
cd gcgrid/geos-chem/data/ExtData/GEOS_0.5x0.666_CH
cd gcgrid/geos-chem/data/ExtData/GEOS_0.5x0.666_NA
cd gcgrid/geos-chem/data/ExtData/GEOS_2x2.5
cd gcgrid/geos-chem/data/ExtData/GEOS_4x5
cd gcgrid/geos-chem/data/ExtData/GEOS_MEAN
cd gcgrid/geos-chem/data/ExtData/GEOS_NATIVE
cd gcgrid/geos-chem/data/ExtData/HEMCO
cd gcgrid/geos-chem/data/ExtData/CHEM_INPUTS

--Melissa Sulprizio 16:52, 8 April 2015 (EDT)

Downloading the HEMCO data directories

The GEOS-Chem Support Team has created a package called hemco_data_download. With this package, you can download the various emissions inventories and related data files for HEMCO to your own disk server. For complete instructions, please see our HEMCO data directories wiki page

--Melissa Sulprizio 16:52, 8 April 2015 (EDT)

For more information

For GCAP users

For those users who wish to run GEOS-Chem with the GISS/GCAP met fields, please contact Loretta Mickley.

--Bob Y. 09:52, 8 March 2010 (EST)

Previous issues that are now resolved

Inconsistency in GEOS-FP files at Harvard and Dalhousie for July 2013

NOTE: This inconsistency was fixed in March 2018 and was validated with benchmark simulations for v11-02e (approved 24 Mar 2018). The solution was to recopy all GEOS-FP met field files from the Dalhousie archive to the Harvard archive.

As always, we recommend downloading all met fields from the Dalhousie shared data directory archive to avoid issues like this in the future.

Prasad Kasibhatla wrote:

I wanted to alert you about something you might know already. I have been trying to run Tomas Sherwen's halogen chem code here and was seeing some substantial differences in my output files compared to his, and I finally traced them to differences in *cld* met files between the Harvard (where I got my met files) and Dalhousie (where he got his met files) archives.
I have only looked at the GEOS_FP 4x5 2013 July *cld* files - I don't know if this is a more widespread issue affecting other met files/met products/years/resolutions. But thought I should alert you.

Chi Li wrote:

I have retrieved the original GMAO GEOS-FP data for July, 2013, and generated the 4x5 A3cld data. I double checked the code and recompiled it, to guarantee that the new way of calculating CLOUD is included in the new processing.
I read in “CLOUD”, “OPTDEPTH” variables and compared the values. The differences were 0 everywhere and every time step when compared with the Dalhousie data for every day. Meanwhile when compared with the Harvard data, the maximum differences in OPTDEPTH could reach ~15 for July 5-31.
I did not compress these data to nc4 but they readily agree with the Dalhousie data. So from my view I would say the Dalhousie archive should represent the more recent updates, at least for this month.
I am not sure how to look more into the difference between Harvard and Dal data. It is strange that the Harvard data agree exactly with Dal and newly processed data on every level and every time step for July 1-4. Anyway, if you recall something else to check with, I am willing to help.

Bob Yantosca wrote:

Odd – it seems like on our end, July 1-4 files were created after the commit that was made to use CLOUD (on 2013-12-12) but July 5-31 were made before (on 2013-11-23 or thereabouts). I am not sure what happened. Now I’m thinking that the Harvard files for this month might not be correct.
One thing – since we use July 2013 as our benchmarking year, this will affect the GC benchmarks, if we change the met fields.

--Melissa Sulprizio (talk) 20:13, 15 August 2017 (UTC)

Wrong No. of vertical layers in A3mstE files for 0.5x0.625 nested regions

NOTE: This inconsistency is fixed since 201710, but not for historical data archive since we are uncertain whether it actually would affect the simulation. We welcome future inquiry and discussion from users of the GEOS_FP 0.5x0.625 data.

Chi Li wrote:

I have another bug in the code to report. After examining the processing Met field processing code, I found another bug that affect the 0.5 degree GEOS-FP nested data (NA, EU, AS, SE, CH regions). That is, the code mistakenly output 72 layers of data in the “A3mstE” files instead of 73. This is due to:
      IF ( doNestCh05 ) THEN
       fName = TRIM( tempDirTmplNestCh05 ) // TRIM( dataTmplNestCh05 )
       gName = 'nested CH 05'
       CALL ExpandDate  ( fName,     yyyymmdd,     000000      )
       CALL StrRepl     ( fName,     '%%%%%%',     'A3mstE'    )
       CALL NcOutFileDef( I_NestCh05,  J_NestCh05, L05x0625,  TIMES_A3,  &
                         xMid_05x0625(I0_ch05:I1_ch05),          &
                         yMid_05x0625(J0_ch05:J1_ch05),          &
                         zEdge_05x0625,                a3Mins,    &
                         gName,    fName,        fOut05NestCh          )
       ENDIF
The “L05x0625” (72 layers) should be ‘L05x0625+1’ (73 layers). Same problems exist for the other 4 nested regions. The nested regions at native resolution (0.25 degree) are not affected.

Bob Yantosca wrote:

As far as I know, nobody is using the GEOS-FP half-degree nested grids (or if there are, we haven’t heard from them).
Also, for the A3mstE data, all of the data fields (e.g. CMFMC) are zero at the top of the atmosphere anyway. Those are all cloud fields, which go to zero at about 20km above the surface.


--Chili (talk) 19:16, 30 October 2017 (UTC)

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