Buoy Sentinel-3A Copernicus Cell 56.00, -11.00

Significant height (Hs) is the average of the highest third of waves, representing what you typically observe. Maximum height (Hmax) is the largest wave measured, often 1.5 to 2 times higher than Hs. A set of large waves can occasionally exceed Hs.

A long period (>12s) means waves have traveled far and carry more energy (groundswell). A short period (<8s) indicates local wind-generated swell, more disorganized. For surfing, longer periods produce more powerful and better-shaped waves.

Buoys typically transmit their data every 30 minutes to 1 hour. The delay between measurement and display depends on the transmission network and our collection system.

The buoy measures direction offshore. Waves change direction as they approach the coast due to refraction (seabed effect). Beach orientation and coastal obstacles also influence the final wave direction.