Weather or Not: Satellite imagery

Types of satellite imagery

History:

According to NASA, the first weather satellite to reach orbit was Vanguard 2 in 1959. Complications rose with this satellite and unfortunately the data was unusable. The following year, T.I.R.O.S.-1 was launched from Cape Canaveral. This mission was successful, and the satellite sent back data for around 80 days. In the 1970s, the Nimbus project began. Seven satellites were sent to space, with six of them being operational. Images were sent back to Earth through the 1990s. This revolutionized weather forecasting for the time and allowed scientists to create more accurate forecasts.

T.I.R.O.S.-1 Credit: NASA
T.I.R.O.S.-1 Credit: NASA
Vanguard 2 Credit: NASA
Vanguard 2 Credit: NASA

P.O.E.S. vs. G.O.E.S.

Up until that point all satellites were Polar Orbiting Environmental Satellites, also known as P.O.E.S. These circle the Earth and sit around 540 miles above the Earth’s surface. This specific type of satellite circles the earth every 102 minutes and passes through the north and south poles. A specific location can be spotted on a P.O.E.S satellite twice a day. NASA reported that the last P.O.E.S satellite launched in 2009 and they currently have two that are operational. This is type for getting a big picture or what’s happening, but not great at tracking individual storms.

This is when the G.O.E.S. series started to launch. G.O.E.S. stands for Geostationary Operational Environmental Satellites. This type of satellite appears to be sitting still while the Earth rotates, but actually it’s just moving at the same speed at the Earth. This continually monitor a specific position on the Earth’s surface. These satellites sit around 22,000 miles above the surface. These images come a long way over the years to give us some of the most high-resolution images and you can even see real-time weather as it’s happening.

As of February 12, 2019, the G.O.E.S.-17 weather satellite is fully operational, just one year after it launched. Not only will this help the west coast of the United States, but will help meteorologists track weather patterns in Hawaii and Alaska where most weather systems start. Meteorologists will be able to see how the storms evolve over a long amount of time to better understand how they will impact the lower 48 states. G.O.E.S.-17, now known as G.O.E.S.-West will send back higher-resolution images that will help better detect wildfires and how far the smoke spreads.

This comes less than 2 years after G.O.E.S.-16 was declared operational and renamed G.O.E.S.-East. Just like G.O.E.S.-West, G.O.E.S.-East also brings some of the highest quality of images scientists have ever seen. This imagery has also helped meteorologists receive the clearest images from hurricanes as well as large storms systems moving across the eastern half of the United States. Unique with the latest satellites, they can map lightning and they have a better detection of fog near the surface.

How Satellites work:

There are sensors attached to the satellite, called radiometers. These measure and scan different wavelengths of radiation from the Earth’s surface. Radiation is measures on the electromagnetic spectrum and the three that emitted are for imagery are: visible, infrared, and microwave radiation. These are then stored and digitized by a computer and given values. Each value is then converted into a pixel and thousands of pixels make an image.

Types of Satellite Imagery:

Visible: This image shows the intensity of the solar radiation or the reflection and that’s how objects are seen. In these types of images clouds area white and you can tell the difference between thinner and thicker clouds. You can also view thunderstorms forming and smoke plume from fires. One limitation is that this imagery depends on sunlight, which means it cannot be used at night.

Visible Satellite Imagery Credit: College of DuPage Weather
Visible Satellite Imagery Credit: College of DuPage Weather

Infrared: This type so imagery depends on the temperature. This means that colder objects will appear white, while warmer objects appear darker. Clouds also show up white in this image, not because of what it is, but how cold it is. You can also tell the altitude of the cloud, because clouds that sit higher in atmosphere are much colder.

Infrared Satellite Imagery Credit: College of DuPage Weather
Infrared Satellite Imagery Credit: College of DuPage Weather

Water Vapor: This image reflects the amount of water vapor in different levels of the atmosphere. You can use this type of imagery to locate the jet stream. It has a tough time detecting low level moisture, which means low level clouds and fog won’t be seen.

Water Vapor Satellite Imagery Credit: College of DuPage Weather
Water Vapor Satellite Imagery Credit: College of DuPage Weather

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