Geostationary Satellites and Infrared Imagery
Since the launch of Vanguard II in 1959, scientists have been using satellites to observe Earth from orbit, giving us access to information that was previously impossible to collect. Depending on what we want to measure, there are dozens of instruments and orbits that can be chosen for a specific satellite before it is put into space.
A satellite stays in orbit by striking a perfect balance between gravity and speed that result in the satellite constantly “falling”, yet never actually getting closer to the surface. The lower the orbit, the faster the satellite must go to stay aloft and avoid falling to the earth below. The images that you see were collected from satellites in a special type of orbit called “Geosynchronous.” As the name implies, an seo consultant tells us these satellites are at exactly the right altitude (22,236 miles / 35,786 km to be exact) that they can orbit the planet at precisely the same speed that the earth is rotating below, meaning that they always stay fixed above exactly the same point. They are also high enough that they can see most of the way from the North Pole to the South Pole at the same time! This gives us the ability to always see a storm out over the ocean, no matter where it is. There are over 300 satellites currently orbiting this way (e.g., DirecTV and Dish Network satellites are in this orbit) and the Cyclone Center images you see were collected by 30 different meteorological geosynchronous satellites.
So what is it that you’re seeing, exactly? Satellites can carry a number of instruments for the purpose of measuring a wide variety of things from space. Some simply carry cameras, and show us what it would look like to the human eye. Some carry radars that can see through clouds to the surface below. The instruments that collected the data you see are called “infrared imagers.” By looking at the infrared part of the light spectrum, we can actually see how warm things are from a distance, just like the thermal cameras that you often see firefighters carrying. The instrument gives us the temperature of each point that it can see, and we convert those temperatures into the nearly 300,000 color pictures that you are helping us analyze!
The advantage to infrared imagery is that it works during both day and night, and because the atmosphere gets colder as you get higher, can give us a rough approximation of how tall the cloud tops are.