RSIG-Related Downloadable Data Files

This page links to supplemental downloadable data files related to RSIG.

This page is intended for users experienced with air quality modeling using the EPA's Fused Air Quality Surfaces Using Downscaling Tool and the Community Multiscale Air Quality (CMAQ) model.

On this page:

Fused Air Quality Surface Using Downscaling (FAQSD) Files

A Bayesian space-time downscaler model is based on statistical modeling research in the development of fused space-time predictive surfaces for air quality.

A Bayesian space-time downscaler model is used to "fuse" daily ozone (8-hr max) and fine particulate air (24-hr average) monitoring data from the National Air Monitoring Stations/State and Local Air Monitoring Stations (NAMS/SLAMS) with 12 km gridded output from the Models-3/Community Multiscale Air Quality (CMAQ) model.

Daily predictions are available at the 2010 US Census Tract centroid locations. The 2002-2008 downscaling outputs were run on 2002-2008 inputs using 2010 Census Tracts to be comparable across the years with the post-2018 downscaler output.  

For more information, refer to the FAQSD technical documentation. 

Disclaimer: The PDFs on this page are not completely formatted for screen readers or other assistive technology. For help with a document, contact Adam Reff, Air Quality Analysis Group, US EPA/OAR/OAQPS/AQAD. 

Disclaimer: The PDFs on this page are not completely formatted for screen readers or other assistive technology. For help with a document, contact Adam Reff, Air Quality Analysis Group, US EPA/OAR/OAQPS/AQAD. 

CMAQ Input Files

The EPA CMAQ model-gridded meteorology, emissions, depositions, and concentrations data subsets can be viewed and saved using RSIG2D/RSIG3D applications.

However, there are other input data files used to run CMAQ that are not viewable in RSIG2D/3D such as:
  • Sector Emissions Files
  • Initial Conditions / Boundary Conditions (ICBC) Files

The CMAQ files that are currently downloadable (sector emissions) can range in size from 5 MB to 500 MB for each simulation day. Also, there are hundreds of files per product, totalling thousands of files. If all the relevant files were combined into a single compressed file, the file would be too large to download from a web site before timing out.

However, if you require such files, you can obtain them in one of two ways:

1) Download and run a custom C-Shell script titled downloader. The downloader script lists all such available data "products" and downloads sets of files from an EPA server to your computer (which should be a Linux workstation you use to run CMAQ, with several terabytes of available disk space).

2) Use the File Oriented Downloader feature of RSIG3D (on the RSIG Web tab).

Downloading CMAQ Files from RSIG

Unsubsetted 2002-2017 CMAQ EQUATES CONUS (continental U.S.) and HEMI (northern hemisphere) files can be downloaded via rsigserver.  

If you are on an EPA computer or on the EPA VPN, then you should access maple.hesc, which is very fast, as shown below:

oz.rtpnc.epa.gov:/Users/tplessel/time curl -k  -L --silent --retry 0 --tcp-nodelay --max-time 0 'http://maple.hesc.epa.gov/rsig/rsigserver?data/CMAQ/EQUATES/CONUS/2017/20170101/CONC.ncf' > CONC.ncf
6.687u 25.673s 2:35.18 20.8%    0+0k 0+0io 6pf+0w
oz.rtpnc.epa.gov:/Users/tplessel/ls -l CONC.ncf
-rw-rw-r--  1 tplessel  staff  12450526316 Dec  3 17:14 CONC.ncf

If you are on an external computer -- and not on the EPA VPN -- then you must access rsigserver from ofmpub as shown below:

Todds-iMac.local:/Users/plessel/time curl -k --silent -L --retry 0 --tcp-nodelay --max-time 0 'https://ofmpub.epa.gov/rsig/rsigserver?data/CMAQ/EQUATES/CONUS/2017/20170102/ACONC.ncf' > ACONC.ncf
36.235u 12.492s 9:36.35 8.4%    0+0k 645+173io 0pf+0w
Todds-iMac.local:/Users/plessel/ls -l ACONC.ncf
3088048 -rw-rw-r--     1 plessel  staff  1581079520 Nov 30 20:02 ACONC.ncf

The download speed depends on the "last mile" of your Internet connection (e.g., at home). The download attempt will disconnect without an error message after 1 hour, resulting in a truncated file.

For example, on a home macOS computer, attempting to download the largest file -- 12GB CONUS CONC.ncf --
disconnected in 1 hour and yielded a 10GB file instead of the complete 12GB file. (Note the download from the EPA computer, oz, took 2.5 minutes and thus was successful.)

An external computer with a VPN connection to maple will be slowed down due to the VPN. 

If possible, avoid downloading via Wi-Fi; instead, download using a wired Ethernet cable.

The following example shows the download of a 1.5GB ACONC.ncf  file in 3 minutes on a Windows laptop, via a home connection using EPA VPN and Ethernet cable.

C:\Users\TPLessel\EDM\utils>curl -k --verbose -L --retry 0 --tcp-nodelay --max-time 0 "https://maple.hesc.epa.gov/rsig/rsigserver?data/CMAQ/EQUATES/CONUS/2017/20170102/ACONC.ncf" > ACONC.ncf
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
* Connected to maple.hesc.epa.gov (134.67.68.221)
…
> GET /rsig/rsigserver?data/CMAQ/EQUATES/CONUS/2017/20170102/ACONC.ncf HTTP/1.1
…
100 1507M    0 1507M    0     0  8465k      0 --:--:--  0:03:02 --:--:-- 9878k

C:\Users\TPLessel\EDM\utils>dir ACONC.ncf
12/03/2021  05:35 PM     1,581,079,520 ACONC.ncf

The URL syntax for downloads is as follows:

  1. https://ofmpub.epa.gov or http://maple.hesc.epa.gov (if reachable from your computer), followed by
  2. /rsig/rsigserver?data/CMAQ/EQUATES/{CONUS,HEMI}/{2002,…2017}/YYYYMMDD/FILE, where FILE is one of the following (with byte sizes shown for CONUS and HEMI):


NAME             CONUS bytes   HEMI bytes
ACONC.ncf         1581079520    339114336
CONC.ncf         12450526316   3249619896
DEP.ncf            303049160     77232584
EMIS.ncf           843247364   9601127904 
GRIDCRO2D            3855440       991824
INTEGRATED.ncf      92239964     23513180
METCRO3D          7205170196   2363362940
METDOT3D           966011968    298598100
WWIND.ncf          480355024    153875160

Paste the URL into a web browser, then choose Save As… to save the renamed file. Or, you can write scripts to download multiple files.

Since there is no server-side processing involved in unsubsetted file downloads, concurrent downloads are possible, i.e., running several scripts at the same time, perhaps downloading different file types for a given date or the same file type for different date ranges. The only limit is the number of concurrent http connections to ofmpub/maple. But since one cannot know how many other users are connected, a good practice is to use no more than 10 concurrent downloads.

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Last updated on January 2, 2025