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 POES vs. GOES

METEOROLOGIST JEFF HABY

POES stands for Polar Operational Environmental Satellites. They revolve around the earth passing over the North and South Polar regions with each revolution. Since the earth is rotating the satellite will pass over a different longitude each time it goes around the earth. They orbit at an elevation of about 750 kilometers above the earth's surface. IF you are lucky they can be seen tracking across the sky at night traveling north to south or south to north. Unlike GOES, the POES are not at a fixed position. Because of this the POES can not constantly monitor the same location. It takes several hours before a POES will travel over the same area. The exception is the areas near the poles. Since the satellite always travels over the polar areas the satellite data for the polar area will be more frequently updated. Since the POES travel over an area the GOES has the worst time observing (due to the curvature of the earth and the GOES fixed position), POES is much better at observing polar areas than GOES. Since POES is much closer to the earth than GOES the POES images can be of a higher resolution.

GOES stands for Geostationary Operational Environmental satellites. Through calculations using mathematics and physics it was determined there is a specific altitude in which an object can orbit around the earth and also orbit at the exact same rate the earth is rotating. This elevation was found to be 35,000 kilometers. This distance is fairly significant (almost 1/10th of the way to the moon). The huge advantage of being at this distance is that the satellite can constantly monitor with each update the same area of the earth. The U.S. has a GOES to monitor the eastern U.S. and adjacent areas (GOES EAST - equator & 75 W) and a GOES to monitor the western U.S. and adjacent areas (GOES WEST - equator & 135 W). There is also a backup in case one of the GOES fails. They like to keep the backup in the eastern position since this position is critical for monitoring hurricanes approaching the U.S. and monitoring the densely populated east coast.