Solar radiation enters the Earth's atmosphere with a portion being scattered by clouds and aerosols.

Processing, archiving and distributing Earth science data
at the NASA Langley Research Center

Frequently Asked Questions and Information - MOPITT Information

MOPITT Frequently Asked Questions

Version 6 data is different than earlier versions in five significant ways:

  1. A small systematic error in the MOPITT geolocation values (latitude and longitude) was identified after the release of the V5 product. This geolocation error has been eliminated in the V6 Level 1, 2, and 3 products.
  2. For V6, processing, meteorological profiles are derived from the NASA MERRA ('Modern-Era Retrospective Analysis For Research And Applications') reanalysis product ( In previous operational processors, meteorological data were derived from NCEP GDAS (Global Data Assimilation System) analysis products.
  3. For V6 the CO a priori is based on a climatology for 2000-2009 simulated with the CAM-Chem model. In earlier products, the a priori was based on a climatology for 1997-2004 and was simulated with the MOZART chemical transport model.
  4. Beginning with the MOPITT V6 products, the format of the archival Level 1, Level 2 and Level 3 data files is switching from HDF-EOS2, based on HDF4 libraries, to HDF-EOS5, based on HDF5 libraries. This represents a major format change and will require that MOPITT product users make major revisions to the tools which they may currently use for opening and reading the content of MOPITT Level 1, 2, or 3 products.
  5. Two minor changes have been made to the contents of the Level 2 product files. First, the a priori total column value has been added; this quantity simply represents the vertically integrated a priori CO profile. Second, the diagnostic 'Water Vapor Climatology Content' has been deleted. This diagnostic was included in previous products because of a data quality issue with the NCEP water vapor profiles. MERRA-based water vapor profiles are not affected by this issue, and so water vapor climatology plays no role in V6 Level 2 processing.

Note: More details can be found in the: MOPITT (Measurements of Pollution in the Troposphere) Version 6 Product User's Guide:

MOPITT has several options for visualizing the data:

1. Quick look Images: Daily and Monthly Plots

2. Interactive Data Viewers             

3. Diagnostics Timeseries

4. Google Earth KMZ Files

ASDC Data Pool:

The Data Pool is an on-line data cache that provides FTP access to select ASDC data products. Data files are stored in directories based on data product and acquisition date.

Examples of using a script to obtain data:


Use the Earthdata Search Tool. Tutorials for this ordering tool are available.


MOPITT Subsetter:

  • This subsetting tool currently operates on MOPITT Version 5 & Version 6 Level 2 products.
  • Update the Output formats to: HDF4, HDF5, NetCDF3 and NetCDF4
  • 1000 granule (file) limit per order.
  • With the subset tool, you will receive only the data points that fall within your specified lat, long bounds.
  • Without subsetting, even if only one point falls within those bounds, you will receive the entire data granule (file).

Basic instructions for authenticating can be found here:
Sample sequence and syntax:


cd ~
touch .netrc
echo "machine login <username> password <password>" > .netrc
(where <username> is your URS username and <password> is your URS password.)
chmod 0600 .netrc


For wget (no clobber of existing files, all files downloaded into current directory):
wget -nc -nH --cut-dirs 4 -r --load-cookies ~/.urs_cookies --save-cookies ~/.urs_cookies --keep-session-cookies --auth-no-challenge