GOES Project FAQ
last updated 22 March 2012
Frequently Asked Questions
G-O-E-S is an acronym that stands for "Geostationary Operational Environmental Satellite".
- "Geostationary" means "it doesn't move with respect to the earth". Actually, GOES flies in an orbit above the equator at the same rate as the equator turns -- one cycle per day. This geostationary orbit is the key feature of the GOES satellite: it can constantly watch the western hemisphere for unpredictable weather.
- "Operational" distinguishes it from "experimental" satellites. GOES works around the clock so we do not miss seeing storms breaking out.
- "Environmental" is in the acronym because GOES also measures atmospheric temperature, moisture, and winds, It even echoes back data from ocean buoys and radio collars on roving bears.
- "Satellite" at the end of the GOES acronym needs no explanation.
There are other agencies using the acronym "GOES", such as the Global Online Enrollment System and Global Online Electronic Services.
GOES takes the pictures of clouds used by the National Weather Service to watch out for severe storms.
The most important job GOES has is to watch hurricanes when they are developing out in the ocean.
The GOES pictures are widely used by TV weather broadcasters.
In addition to taking pictures, GOES carries instruments to measure atmospheric temperature and moisture, to monitor the particles and fields around the spacecraft, to help search and rescue operations, and to echo remote data collection platforms (e.g. buoys). The GOES mission is briefly outlined in the GOES brochure, and explained in technical detail in the GOES data book.
NESDIS runs a portal to all their satellite data products.
Digital datasets and/or hardcopy can be ordered for the price of copying, shipping and handling from the National Climatic Data Center (NCDC).
NCDC also keeps some recent satellite data on-line.
NOAA keeps a complete GOES digital data archive back to 1979.
You can download raw broadcast data from the NOAA's CLASS Archives, in the GOES format known as GVAR.
Some other interesting servers of weather and earth science imagery are:
There are many, many web servers of recent GOES images: NASA's list. For example, there is NOAA's Environmental Visualization Program.
At this NASA location, there are:
The TIFF-formatted GOES images are from GSFC calibrated and navigated.
The MODIS true-color images from NASA's "Blue Marble" global map are used as a background, projected as though viewed from the GOES satellite location.
Semi-transparent layers of GOES infrared and visible images are enhanced and layered on top of that color background.
The details are in a thousand lines of IDL software.
Hardcopy of raw GOES images can be ordered for the price of copying, shipping and handling from NOAA's National Climatic Data Center (NCDC):
NCDC
Federal Building
151 Patton Avenue
Asheville, NC 28801-5001
Phone 704-271-4800 option#5
Fax 704-271-4876
email satorder@ncdc.noaa.gov
In addition, many commercial print shops know how to make hardcopy of on-line images.
For example, JPL in Pasadena CA posts a list of west coast printers who know how to print satellite images.
In the Washington DC area, Capital Presentations does digital printing.
(NASA is not endorsing these particular shops.)
For a local printer, look in your Yellow Pages, give them the exact URL, and they can download and print a hardcopy picture.
The 27-meter-long GOES-I/M satellite is too fragile to deploy on the ground.
So, there is no such thing as a photo of a deployed GOES satellite, only artist's renderings:
http://goes.gsfc.nasa.gov/images/thenextgeneration.jpg
There are pictures of a GOES-I/M satellite folded up for shipping and launch. It is an 8-foot cube of antennas and gold foil.
We have artist's drawings of GOES-N/P
There are more illustrations in the GOES brochures.
The GOES program is over 30 years old.
NASA once wrote an online history of GOES-1 through GOES-10.
Thumbnail histories of the GOES launch dates and orbit locations can be queried in NASA's database of satellites.
Information about GOES is spread over a number of web sites.
NOAA/NESDIS Office of Satellite Operations posts routine information, plus
the daily news,
as does the Satellite Services Division.
We keep a central index here.
We also try to keep track of all the other civilian geosynchronous weather satellites.
GOES is not as good at sea surface temperature (SST) mesurements as the low-earth orbiters.
A good web site for sea surface temperature is:
Satellite Sea Surface Temperatures from NOAA-PMEL
GOES images appear as though they were taken from a fixed point-of-view directly above the equator.
Ideally, the same line-and-pixel corresponds to the same latitude-and-longitude in every GOES image.
However, it is not easy to convert from these image coordinates to geographic coordinates, using NOAA's algorithms.
At NASA-GSFC, a "nav" file for each sector lists the latitude and longitude for each pixel (see the corresponding "readme.nav.txt" file for details).
The "nav" file is used to draw geopolitcal maps in TIFF and GIF formats that you can use as an overlay.
There is a cryptic comment at the end of GSFC-generated GOES digital images in TIFF format, or as a "latest.info" text file in a directory of LZW-TIF images. For example:
GOES 12 Imager frame 113 at UTC 20:45:18.281 day 121 of 2003
Vis pixels: 4025, 24860 lines: 2445, 13264
Vis Lon :999999,999999 Lat :999999,999999
Imager ch1:count(0,1023) => [(albdo-0)/0.4]^1 =Uchar> (0,255)
(xscale,yscale) => (0.047619,0.0833333)
Vis pixels: 3650, 28850 lines: 2250, 14250
(xstride,ystride) => (21,12)
- The 1st line is information about the start-of-frame.
- The 2nd line lists the first and last pixel and line in the original frame, in the scan coordinate system of the Imager.
- The 3rd line lists the longitude and latitude of the northwest and southeast corners of the original frame, with all 9's when the corner is in outer space.
- The 4th line lists the radiometric transformation performed on the original 10-bit (count) data (e.g. convert counts to calibrated albedo with zero offset, and re-scale by dividing by 0.4), followed by the word-type of the digital pixels in the TIFF image (e.g. Uchar is unsigned, one-byte "character" data, with integer values between 0 and 255). For sectors that are used for 8-bit greyscale computer-screen looks, the calibration is commonly NOAA's "mode-A" scheme.
- The 5th line lists the geometric re-scaling factor applied to the original data.
- The 6th line lists the first and last pixel and line in the sector of this TIFF image, in the scan coordinate system of the Imager.
- The 7th line lists the resampling step-size ("stride") taken within the original image (e.g. every 21st pixel and every 12th line).
The Imager over-samples pixels along a line by 7:4, so publicly distributed images are normally scaled down by a factor of 4/7 east-west to present true perspective, and to make the Earth look round instead of oblate.
GOES image calibration is performed using NOAA's calibration coefficients embedded in the broadcast data stream. For more information on GOES calibration, check out the tech notes.
NOAA's GOES products include: winds (water vapor, cloud motion, gradient), temperature/moisture profiles, cloud amount and height (ASOS), lifted index, precipitable water, surface temperature, and GEWEX insolation products.
For some facts about the international satellite programs, check our Geo-News page.
The international websites posting realtime geosynchronous images are:
For more links, check our list of international satellite image servers.
For maps and land-resolving satellite images, go to Google Earth.
For the basic "what's the weather now, and 3 day forecast", try
For more details, check our big list of lists of the international weather and satellite web servers.
For kid's educational information, start with Dr. Fred, and check out his weather links.
For specfic weather-oriented project ideas, try:
Try some other FAQ pages:
For more technical information, try:
Mailto:Dennis.Chesters@nasa.gov
GOES Project
Why is it called "GOES"?
