Significant wave height is determined from the shape of the return radar pulse of the altimeter. A calm sea with low waves returns a sharp pulse, whereas a rough sea with high waves returns a stretched pulse.
In general, there is a high degree of correlation between wind speed and wave height. The strongest winds are found in the southern oceans. Accordingly the highest waves, represented in red, are also found in the southern oceans and can rise over six meters in height. The lowest waves, indicated in dark blue, are found primarily in the tropical and subtropical oceans where the wind speeds are the lowest.
The simultaneous observations of wind speed and wave height by TOPEX/Poseidon will help improve our ability to forecast ocean waves.
