Indicazione di onde e tempeste
SEA is the name given to the waves formed by the wind within a particular generating area. The height of the waves will depend on the length of time the wind has been blowing from a particular direction, the fetch (distance over which the waves have travelled), currents and strength of wind. Sea states are measured in accordance with a scale as follows:
|
Code 0 1 2 3 4 5 6 7 8 9 |
Calm — glassy smooth Calm — rippled surface Smooth wavelets Slight Moderate Rough Very rough High Very high Phenomenal |
Height in metres
0 0-0.1 0.1-0.5 0.5-1.25 1.25-2.5 2.5-4.0 4.0-6.0 6.0-9.0 9.0-14.0 Over 14.0 |
|
SWELL is the wave motion caused by a meteorological event (such as a storm). As the swell moves away from the generating area it will die down but reatin its wavelength and speed. Swell can be measured as follows:
| Length
Short Average Long Height Low Moderate Heavy |
Metres
0-100 100-200 Over 200 Metres 0-2 2-4 Over 4 |