Wave data (real time)

Ocean waves are mainly caused by wind. The wave heights are affected by 3 factors:

• wind speed – the strength of the wind transferring momentum to the ocean surface;
• duration – the length of time the wind blows;
• fetch –  the distance over which the wind blows.

Generally, the stronger the wind and the more time and distance the wind blows, the larger the waves generated (known as swell). Winds can also cause small steep waves or chop, often referred to as sea waves.

How the waverider works

The waverider surface displacement radio signal is received at a shore station. The waverider receiver processes this signal and calculates waverider heave (height of each wave). This data is then sent to the Department of Transport to provide near real-time wave information. 

About waves

The wave climate at any location is a combination of sea and swell waves referred to as the total wave. 

Swell waves are generated from distant storms, normally in the Southern Ocean. Unless there is cyclone activity in the north, the same swell patterns are observed to varying heights and at different times along the coast. Swell waves are long and smooth and are generally characterised by a wave period greater than 8 seconds. The wave period is the time between consecutive wave crests. 

Sea waves are generated by local winds and are usually short and choppy. They have shorter wavelengths and periods than swell waves and are generally steeper.

Waves are commonly characterised by their Significant wave height (Hs), which is the average of the highest one-third (33%) of the waves (measured from trough to crest) that occur in a given period. The significant wave height is the average of the highest waves, however many individual waves will probably be much higher. 

Caution: Maximum wave height (Hmax) can be up to twice the size of the Significant wave height (Hs).

Further information about wave data can be obtained from the following resources: