GOES-10, the newest of the U.S.'s operational geostationary satellite, was launched in the fall of 1997 and became operational in July, 1998. GOES-8 was launched in the spring of 1994 and became operational in June, 1995. Visible Images Visible satellite images record visible light from the sun reflected back to the satellite by cloud tops, land surfaces and ocean surfaces.
Ocean surfaces tend to reflect the least visible light, so they tend to be the darkest features.
Infrared Images Infrared satellite images record invisible infrared radiation emitted directly by cloud tops, land surfaces or ocean surfaces. The warmer an object is, the more intensely it emits radiation, so the intensity with which a feature on earth emits infrared radiation tells us about that feature's temperature. On the infrared images available at most WWWeb weather sites, including SFSU's California Regional Weather Server, darker shades of gray represent relatively warmer features, and lighter shades of gray represent relatively colder features. On the color-enhanced infrared images available at SFSU's California Regional Weather Server, colors other than gray are assigned to some of the coldest temperatures. Far from the polar regions, features this cold invariably comprise the tops of clouds in the upper troposphere or lower stratosphere and are often associated with thunderstorms, hurricanes or midlatitude cyclones.