Satellite Meteorology

Article excerpt

What are the different types of weather satellite?

Two types of satellite provide weather data: geostationary and polar-orbiting. Geostationary satellites orbit above the equator at a height of 35,780 kilometres. Their orbits are synchronous with the Earth's rotation and thus 'hang' above the same spot on the ground. Polar-orbiting satellites orbit at a height of 830 kilometres and pass over the Earth from pole to pole. Each orbit takes one hour and 42 minutes, and during this time the Earth turns by about 25[degrees], so the satellite views a different part of the surface with each pass. In the UK, we receive images from two sets of three passes from two satellites, one set during the day, the other at night.

How do the images received differ?

Pictures from geostationary satellites are not very detailed because of the height of the orbit and the oblique angle of view when looking at higher latitudes. Images from polar-orbiting satellites provide more detail for the forecaster; the disadvantage is that they don't provide a constant view.

How long have meteorologists had access to this technology?

The first weather satellite was launched on 1 April 1960, and the subsequent launch of other observing systems has resulted in the creation of an imaging network on a global scale. Geographical coverage is now greatly improved, especially for areas such as the oceans. …