Satellites

fig8.jpgThis is a picture of the NOAA AVHRR satellite. NOAA stands for the National Oceanic and Atmospheric Administration run by the United States government, and AVHRR stands for Advanced Very High Resolution Radiometer, which describes what the satellite does. It flies at 20,000 mph at an altitude of about 500 miles, and simply circles the earth about the poles.
It flies over our head every 12 hours.

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Since it's only 500 miles up, it can only see small pieces of the earth at a time (the red band on the globe). We begin gathering data from it once it rises above our horizon, and stop collecting data when it drops below the next horizon (see the horizon image). The total coverage area (shown below) is the area we can see on any given day. The satellite "sees" the earth somewhat like we do, looking at visible light (red, orange, yellow, green, blue, violet). But, it can also see temperatures, which is what we use it for. If you've ever seen the movie "Predator" with Arnold Swartzenheger, you know what I mean when I say "see temperature".

At any given time, there are usually 3 of these AVHRR satellites up in orbit, and we track all three of them here at the COOL room. That gives us 6 passes over New Jersey each day.fig10.jpg

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The overpass times (give or take 1 hour) are 1:30 AM, 4:30 AM, 7:30 AM, 1:30 PM, 4:30 PM and 7:30 PM.