Weather studies from space
Do you want to know whether it will rain on your picnic or be sunny for your day trip? Nowadays, it is easy to find out by looking at satellite images on TV or the Internet.
Only a few decades ago, weather forecasts were much more hit and miss. One of the problems was that weather stations were only set up in a few locations. Everywhere else, the weather conditions were almost a mystery.
Nowadays, satellites give full coverage of the entire Earth. Every cloud system and storm can be seen as it forms and changes.
The first weather satellite, TIROS (Television and InfraRed Observation Satellite), was launched on 1 April 1960. It carried two TV cameras that beamed grainy images back down to the surface.
Today's weather satellites are larger and far more advanced. They provide forecasters with extremely detailed images and other useful information about the atmosphere and oceans, that help them refine their predictions. Some weather satellites always hover over the same part of the Earth's surface. They stay in geostationary orbits, 36 000 km above the equator.
Others circle the Earth from the North to the South Pole and back. They travel much nearer to the surface (some as low as 800 km) and provide highly detailed, close-up pictures of weather systems all over the world.