Information


Information


To have a better understanding about satellite products, Applied Geophysics Center provides basic information about all type of satellite images. Thus, It helps readers gaining valuable knowledge of satellite products, and remote-sensing products to be specific.. 

Definition of visible satellite image:

Visible satellite imagery can only be viewed during the day when clouds reflect sunlight. On satellite image see, the clouds show white, the ground is usually gray and the water is dark. In winter, the snow-covered ground will be white, can cause  for distinguishing the cloud will  more difficult. To help distinguish between clouds and snow, image loops can be helpful, clouds will move while snow will not. Snow-covered ground can also be determined by inspection topographic features such as rivers and lakes. The river will remain dark in the image as long as it is not frozen. If the rivers cannot see, it  might be  cloud cover. Satellite image sighting also useful for detecting the formation of thunderclouds. Satellites will detect  thunderstorms are developing at the earliest stage before they are detected on radar.

Definition of Infrared satellite image :

Infrared satellite images indicate  all day and night clouds. Instead of capturing the reflection from the clouds because of sunlight, clouds are identified by sensors of satellites measuring the radiant heat emanating from them. These sensors also measure the heat emitted from the earth is surface. Clouds are colder than soil and water so they can easily be identified. Infrared satellite imagery is often used to calculate the intensity of thunderstorms, whirlwinds, and strong thunderstorms that will often have very cold cloud peaks. Infrared satellite images can also be used to identify low-level haze and clouds. Fog satellite products that combine two different infrared channels to identify fog and low clouds at night are often represented by dark areas on the image.

 

Definition of water vapor satellite image (The English name is WATER VAPOR):

Water vapor images indicate the amount of humidity  in the upper atmosphere(from about 4500m  to 9150m). Area having highest humidity will have the lightest color and dry area will have darker color. Water vapor image  is useful to indicate areas  that will have heavy rainfall or thunderstorms.

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