Satellite Meteorology Interpreting Satellite Pictures
History of Satellite Meteorology
Satellite Meteorology has its origins from the military. The Germans developed the science that has since become known as rocketry. Hitler exhausted a tremendous amount of resources trying to develop a mechanism capable of delivering explosives to a target several hundred or thousand miles away. This wartime effort resulted in the development of the first rockets.
The first rockets were fueled by explosives similar to TNT. TNT is the primary component in dynamite and its uses as an explosive chemical have been known since the time of the ancient Chinese. Pre-World War II rockets had the capability to reach targets several thousands of miles from their launch points.
It wasn't until post World War II in the late 1940s that technology leftover from the war was perceived to have significant value to the scientific communities of meteorologists, astronauts, and astronomers.
The first weather satellite was utilized in 1959 and was called Tiros. As is the case with much of technology in the world today, satellite meteorology had its origins in military and intelligence type operations. The primary purpose of putting a camera aboard a satellite in space was to take spy pictures. There certainly were many meteorologists and scientists excited about the meteorological monitoring capabilities that would be acquired, but most of the funding came from agencies interested in gaining an edge on military and intelligence capabilities.
The first satellite picture announced to the world was of a tropical storm in the Pacific Ocean. That simple photograph greatly enhanced meteorologists' understanding of tropical weather systems tremendously in only a matter of a few weeks.
Satellite meteorology was certainly one of the more modern milestones of weather forecasting.
Remote sensing
The practice of using instruments to monitor the weather from a distance is called remote sensing. "Remote" as in from a distance and "sensing" as in taking measurements. Radars and satellites are the primary remote sensing instruments used by meteorologists.
Satellite orbits
There are basically two types of meteorological satellites in operation today. Geosynchronous satellites and polar orbiting satellites. A geosynchronous satellite remains at one location above the Earth and orbits the Earth at the same speed as the Earth's rotation rate.
Geosynchronous satellites require an altitude of 43,000 km to remain in a geosynchronous orbit.
Why don't satellites fall out of the sky? The force of Earth's gravity pulling the satellite toward Earth is exactly counterbalanced by centripetal force pulling the satellite outward such that the satellite remains in orbit around the Earth. Geosynchronous satellites give scientists the benefit of monitoring one region of the Earth for an extended period of time.
Polar satellites orbit the Earth medidionally.
Modern satellite missions
There are many weather satellites in operation today. The GOES (Geosynchronous Orbiting Environmental Satellite) series is a system of satellites providing Europe, North and South America, Africa, and the Pacific Ocean with continuous weather satellite information.
Satellites take photographs of the Earth with cameras that capture visible light. They also produce images by capturing radiation at the infrared portion of the electromagnetic spectrum.
As we learned, all objects not at absolute zero radiate a finite amount of energy as a function of the fourth power of their temperature. Clouds radiate different amounts of energy as a function of their temperature which is in turn a function of their elevation in the atmosphere. The higher up a cloud extends into the atmosphere, the colder it is. Intense storm systems and hurricanes are often associated with cumulonimbus clouds that extend high up into the atmosphere.
There are many other satellite missions in operation today. One that was launched in November 1997 is called TRMM the Tropical Rainfall Measuring Mission. Its purpose is to measure rainfall over the tropical oceans.