First Alert Weather In-Depth: The ‘eyes’ of a meteorologist
ROCHESTER, N.Y. — Meteorologists have different types of tools that available to help us to forecast the weather. But one of the most important devices in our arsenal are satellites.
Satellites help us to look at the Earth and specifically track the weather across the globe. But, just as there are different categories of vehicles on the road, there are also different types of satellites.
First, is a polar orbiting satellite which is located about 500 miles above the ground. As the name suggests, it orbits the Earth from the north pole to the south pole and back to the north pole. This can happen 14 times a day. This is a lower orbiting satellite which gives us a view of very specific data, such as at ice coverage, ocean waves or deforestation. We do not use that data very often, but it is just as important for specific applications.
Another type of satellite is called a geostationary satellite — which is more than 22,000 above the equator. This also orbits the Earth, but moves in the same direction as the Earth spins. It is important to note that it obits at a speed or rate that keeps it in the same position relative to a spot on Earth. There are two primary geostationary satellites, one is located over the East Coast and the other over the West Coast. According to the National Oceanic and Atmospheric Administration (NOAA), we now have five of these types meteorological satellites available in order to provide coverage over most of the Earth.
For our purposes as meteorologists, it is the visible satellite image that is used most often. This imagery takes advantage of the light from the sun to illuminate the clouds. This gives us a higher resolution during the day. But what do we do at night when we do not have sun to light the clouds? Then we shift to infrared imagery. This uses long-wave energy, which is outgoing radiation. This tool will analyze the amount of heat emanating from the atmosphere and calculates the likely location of clouds.
Some folks may think cloud images are of little use. That is not true. Think of when a hurricane starts out in the middle of the ocean. Nobody’s out there to the tell us it’s coming. The satellite imagery is the ‘eyes’ for the meteorologist, and important tool that is needed to forecast the weather.