These images come from satellites which remain above a fixed
point on the Earth (i.e. they are "geostationary"). The infrared
picture shows the same view but looking at a part of the spectrum
which our eyes do not detect. The infrared pictures allow us to
measure the temperature of the cloud tops, which can be used to
determine their height. The whiter clouds are colder than the
greyer clouds in this image. Infrared images can be recorded 24
hours a day. Visible pictures can only be made during daylight
hours. Coastlines and lines of latitude and longitude have been
added to the images and they have been altered to mercator projection.
These images are in JPEG format and occupy about 75 Kbytes. The
Infrared images should be updated with the 00:00, 06:00, 12:00
and 18:00 GMT pictures. It usually takes about 1hr 30 min. for
these images to be processed and be updated on the web site.