Launch date: June 19, 1999
Type of orbit: sun-synchronous, i.e. the satellite crosses a certain point always at the same time of the day.
elevation: 800 km
Inclination of the orbit: 98,6 degrees compared to the equatorial plan.
Period of revolution: 102 minutes, 14 orbits are achieved per day on ascending and descending passes. The period of revolution is the time taken for the satellite to complete a full rotation of the Earth.
A scatterometer is a high frequency (13,4 gigahertz) microwave radar designed specifically to measure ocean near-surface wind speed and direction. As the wind blows over the ocean, the surface is roughened by the generation of centimeter scale capillary waves. These, in turn, modify the surface reflected signal properties.
This instrument scans a roughly 1800 km wide swath. The instrument collects approximately 400,000 measurements and covers 90% of Earth's surface in one day. The resolution is 25 kilometers.
All weather wind-speed measurements are not stopped by the clouds. However, measurement is disturbed by all phenomenon which destroys the capillary waves: rain, very weak winds or strong winds (higher than 20 m/s). Between 3 m/s and 20 m/s, the accuracy on wind intensity is 2 m/s and the accuracy on the direction is 20 degrees.