Here's what New York looks like from space this morning. Satellite instruments that observe the weather are nothing more than very sophisticated, very expensive digital cameras. The images we normally see on television come from the Geostationary Operational Environmental Satellite, or GOES. GOES is positioned 22,300 miles (35,800 km) above the equator. At that distance the satellite is in a geosynchronous orbit --it stays above the same spot on the Earth. The National Weather Service has two operational GOES satellites in orbit: GOES-East over the western Atlantic and GOES-West over the eastern Pacific.
Each satellite has an imager, which looks at the earth in one visible and four infrared wavelength ranges. The Earth emits radiation to space in infrared wavelengths. Colder objects emit more of their energy at longer wavelengths. High clouds are colder than clouds closer to the Earth's surface. Thus, by observing infrared radiation emitted by the Earth you are observing clouds. Plus there's not much to see in the visible part of the spectrum at night. The spatial resolution, or smallest pixel size, of the GOES imagers depends on the wavelength being observed but ranges from 1 km to 8 km. Seeing something as small as 1 km, six-tenths of a mile, on a side from that 22,300 miles away is pretty impressive. GOES also carries the very cool Solar X-ray imager.
Some of Gothamist's favorite places to look at GOES and other weather satellite imagery are the Geostationary Satellite Server, the NASA Global Hydrology and Climate Center, the University of Wisconsin's Naval Research Laboratory, and NOAA's Atlantic and Caribbean Tropical Satellite Imagery site.
What are your favorite sources of satellite images? We'd love to hear from you!