
The adjacent animation shows GOES-8 weather satellite images over a 72-hour period from Dec. 29, 1996 through Jan. 1, 1997. This is a geosynchrous satellite, which means that it orbits the Earth with the same period as the Earth's rotation and therefore appears to be essentially motionless over a fixed position on the Earth's surface. For GOES-8 this fixed position looks down on North and South America.
In these composite images red indicates visible light (reflected sunlight), green indicates the 11 micron IR channel (thermal emission), and blue indicates the 3.9 micron channel (thermal + sunlight). At night the images are blue and green. The three periods of daylight in this 72 hour sequence are clearly visible as red-orange regions moving from East to West (right to left). In the IR channels, the natural intensity pattern has been inverted: warmer is darker, so that cool cloudtops stand out brightly.
Here is a similar weather animation (1.49 MB animated GIF) using GOES-8/9 IR images for North America over a 2 day period from December 31, 1996 through January 1, 1997. The large weather systems that move ashore from the Pacific in this animation produced catastrophic flooding in California, Oregon, and Washington in early January, 1997.