CAMEX-3 GOES-8 Products

Table of Contents

In support of the third Convection and Moisture Experiment (CAMEX-3), imagery from the Geostationary Operational Environmental Satellite 8 (GOES-8) was collected and archived. Information about CAMEX-3 is found at the homepage located at http://camex.nsstc.nasa.gov/camex3.

GOES-8 imagery was collected at the Global Hydrology and Climate Center (http://wwwghcc.nsstc.nasa.gov) throughout the experiment. Images from the satellite were saved as McIdas areas and cropped to show the region of the globe from 60 to 100 degrees West, and 10 to 40 degrees north-- an example is shown. Generally, images are available for all dates between 5 August and 1 October, 1998 at times h+00:15 and h+00:45.

Three channels were archived: channel 1-- visible (0.65 microns), channel 2-- infrared (11 microns) and channel 3-- known as the water vapor channel (6.75 microns). Data is archived in McIdas format. [NOTE: If you do not have McIdas software installed on your machine, reading these data becomes difficult! ] In addition to the McIdas areas are browse images which are saved in .gif format.

Data resolution for visible imagery is 1 km. at nadir, IR is 4 km., and water vapor is 8 km.

Both the McIdas area files and the .gif browse images are similarly named and maintained. In each case, one UTC day worth of data is tarred together yielding a file name which looks like:

• cmx3g8_1998.ddd_daily.tar               for the McIdas data files, and

• cmx3g8B_1998.ddd_daily.tar           for the browse image files.

In each of the above examples 'ddd' represents the day of year. Once 'untarred' using the unix command 'tar xvf [filename]' each of these yields the individual data or browse image files. The filename format for these appears as:

• cmx3g8_xx_1998.ddd_tttt_mcidas.ara    for McIdas area data files, and

• cmx3g8B_xx_1998.ddd_tttt.gif                  for browse image files.

Note that once again 'ddd' means day of year, and as one would surmise, 'tttt' represents the UTC of the image/data. Since there are three channels worth of data available at each image time, 'xx' represents the channel: 'vs' implies visible wavelengths, 'ir' is infrared, and 'wv' is water vapor. Thus, assuming that all images were collected for the given day, you would have 48 images each of infra-red and watervapor, and batween 35 and 40 visible images (no nighttime visible images were archived) per day for both data and browse imagery. These daily tar files are compressed, via gzip, for archival and distribution.

Mentioned previously, data is in McIdas areas. If you have McIdas, you know what you are dealing with. If not, then unless you have custom software which allows you to extract informtion from McIdas areas these data will be of little use to you.

Browse products are helpful in visualization, and because the CAMEX-3 browse imagery are all 'cropped' to the same dimensions with the same corner points, it is a trivial matter to construct .gif movies/animations and the like.

There are no specific technical references for these data, but here are some potentially useful URLs:

http://www.ssec.wisc.edu/mcidas/          This is the McIDAS home page
http://www.osd.noaa.gov               Check here for other satellite data

Contact Information

To order these data or for further information, please contact:

Global Hydrology Resource Center
User Services
320 Sparkman Drive
Huntsville, AL 35805
Phone: 256-961-7932
E-mail: support-ghrc@earthdata.nasa.gov
Web: http://ghrc.nsstc.nasa.gov/