NRT (Near Real Time) swell system
Tracking swell waves from space is very important because they are generally preceded by calm water, making it impossible to detect their arrival from shore. Envisat’s Wave Mode acquires 10 by 5 km small images, or 'imagettes', of the sea surface every 100 km along the satellite orbit. These small images, which depict the wave groups, are then mathematically transformed into wave energy and direction, called ocean-wave spectra.
In this animation, you can see: Swell systems in Near Real Time from 18-25 January 2008 across the Pacific Ocean as observed by Envisat’s ASAR Wave Mode. Colour indicates wavelength, with red being the longest.
Last update: 7 May 2010