Unlike visible images, infrared images are available even when there is no daylight. A combination of visible and infrared images is very useful and can help distinguish between high and low cloud. For example, if a bright area appears on both the infrared and visible images in the same place, it is likely to be thick, high cloud. However, if the area appears bright on the visible image but dark on the infrared one, it is probably low cloud or perhaps fog. Back to top Using satellite images Satellite images provide a 'real-time' view of weather systems, and their use can help lessons come to life.
Satellite images are available from many web sites.
Many schools and colleges also have systems that provide access to live weather satellite images and allow a time-lapse sequence of images to be displayed showing how weather systems develop over time. CD-ROMs that provide a gallery of images and give further technical information on satellites are also available . In general, the clouds shown in satellite pictures can be classified as layer clouds or convective clouds. Layer clouds tend to cover large areas and are indicated on a satellite picture by an area of uniform brightness. This type of cloud is formed by a large-scale rising motion in the atmosphere, often associated with depressions or fronts.