• What is a Satellite Image?
• What is a Standard Infrared Satellite Image?
• What is an Enhanced Infrared Satellite Image?
• What is a Visible Satellite Image?
• What is a Visible-Infrared Satellite Image?
• What is a Color Water Vapor Satellite Image?
• What is a Satellite and Radar Image?

What is a Satellite Image?

Satellite images are measurements of the Earth (some are "photos" in the classic sense) from high in space, taken by governmental satellites, which are usually used to show clouds and cloud movement. AccuWeather uses GOES-8, GOES-10, Meteosat and GMS Satellites to make dozens of different satellite sectors available, each showing clouds over a different area.

What is a Standard Infrared Satellite Image?

The Standard Infrared satellite images produced by AccuWeather give an excellent representation of the location and intensity of the actual clouds despite being based upon temperatures. The reason for this is that the temperatures shown are the highest level of clouds above the earth. Since the atmosphere gets colder as you go higher up (at least in the lower part of the atmosphere where clouds typically occur) the colder the temperature that shows up on an infrared image, the higher the clouds that are being sensed by the temperatures. When there are no clouds at all, the temperature of the earth is sensed and this is typically warmer than if there were clouds above the location. The problem with this is that sometimes on clear, very cold nights the temperature at the earth's surface is colder than temperatures aloft (this is referred to as an inversion). To correct this problem, complex algorithms are necessary to determine that skies are clear rather than cloudy in this case. Also when low clouds and fog exist, the temperature of low clouds and fog is typically very close to that of the earth's surface so algorithms are also needed to determine that clouds exist in these cases rather than clear skies. AccuWeather meteorologists, programmers and system engineers have devoted more than ten person years of time developing algorithms that determine which areas are cloudy and which are clear in an infrared satellite image.

What is an Enhanced Infrared Satellite Image?

AccuWeather's exclusive Enhanced Infrared Satellite is similar to the Standard Satellite, but it turns from white to vibrant colors with colder temperatures, highlighting the stronger storms. The raw satellite data also allows the user to see more detail than the standard image, as well as land and sea surface temperatures. Normal Infrared satellites, (such as AccuWeather's Standard Infrared Images), are greyscale, with darker greys representing hotter temperatures (lower clouds) and whites representing colder temperatures (higher clouds, usually stronger storms). The problem with this type of satellite is that it is difficult to see the small differences in temperature of the clouds near the edge of the scale, and turning grey to white is sometimes not visible enough to the naked eye. AccuWeather takes the last several dozen levels of white and translates them to eyecatching colors so the strongest storms easily stand out. This new raw image provides much more detail than the Standard Infrared image, showing things such as cold air coming down from Canada, or the warm water of the Gulf Stream. If there is any question of whether you are seeing clouds or not, that can be answered in an animation.

What is a Visible Satellite Image?

Visible satellite images are literally "photographs" of the earth. They show clouds in the visible portion of the electromagnetic spectrum. Because they see what you or I would, these images will be blank during the night. Visible satellites generally show low clouds, fog and snowcover better than infrared images and can be very detailed.

What is a Visible-Infrared Satellite Image?

This type of satellite is new to the Internet; it combines the Visible Satellite with the Infrared Satellite to make one image which shows the most detail possible, 24 hours a day. Often quick-moving upper-level clouds can be seen skirting over lower-level clouds, especially in an animation. During the nighttime the image is a Standard Infrared image, which is greyscale, with black being the hottest temperatures, and white being the coldest. Generally colder cloud tops indicate stronger storms. When the sun rises, the standard Infrared image is mixed with the Visible satellite image. Blue areas are from the Infrared; Yellow areas are from the visible; White areas are a mix of the two. Without changing to a separate image or comparing images, you are able to see the temperature data from the IR mixed with the "camera" detail of the Visible shot, and can see the maximum amount of Visible data present without the rest of the image turning black at night. You can also track cloud areas from the composite daytime image into the greyscale IR nighttime image instead of guessing which areas are clouds vs. which areas are temperatures (sea-surface or surface).

What is a Color Water Vapor Satellite Image?

You may have seen water vapor satellites before, but never one like this. AccuWeather's Color Water Vapor Satellite shows detailed water vapor data on an eye-appealing scale from deep red to bright green (dry to moist) which enables the user to easily pick out upper-level circulations and intrusions of wet or dry air. Water Vapor images primarily show moisture from 18000 feet above the earth's surface to the top of the atmosphere. This helps in identifying upper level winds and jet streams for use as a tool to predict weather system movement, especially tropical systems. For example, jet streams can be identified as quickly moving areas of bright green, while the dry slot of a low pressure system can be seen as red wrapping counterclockwise around the low. Large thunderstorms which reach high into the atmosphere will be picked up as bright green, as will powerful moisture-laden hurricanes.

What is a Satellite and Radar Image?

The Satellite/Radar image overlays AccuWeather's Composite radar onto the Standard Infrared image. This allows the user to see not only current precipitation but also surrounding clouds.