Outdoor Education…Character development through the outdoors

Surf AWARENESS

The global circulation

Everything on Earth is driven directly or indirectly by the Sun's energy. The uneven heating of the Earths surface by the sun is the first link in a chain of events leading to cyclones, thunder storms, blizzards and those ocean-borne depressions responsible for the waves a surfer rides.

A rotating Earth with land, sea and seasons

Land and water respond differently when heated and cooled. While the temperature on continents swings many tens of degrees from winter to summer, the oceans keep a more constant average temperature. So summer means warm land, not-so-warm sea. And winter means cold land, not-so-cold sea. Therefore, in winter air movement is a lot more than in summer.

Winds influence on water

The main creator of waves is wind blowing over the surface of water. At first, ripples are formed on a calm surface, which are easier for wind to get a grip on and increase their size.

As ripples grow, small disturbances of rotating air form between the ripples adding more height to the waves, which in turn creates more uniform pockets of turbulence between the quickly growing waves. Surface tension is no longer strong enough to restore the rippling disturbance and gravity now attempts to push the waves back down.

This cycle increases wave height until gravity limits further growth and the wave reaches saturation point.

Science of the Surf Ep 1- Where do waves come from.mp4

Auckland's West Coast

This weather map shows a strong south westerly flow over New Zealand. The orange arrow shows the direction of the wind and therefore swell. In this situation, Auckland’s West Coast beaches would be hit by a very large swell.

Swell v Land = Surf

Waves will break when the bottom part of the wave is slowed down so much that the top of the wave overtakes it and spills forward.

Science of the Surf Ep 2- Waves.mp4

Sea Breezes

A sea-breeze (or onshore breeze) is a wind from the sea that develops over land near coasts. It is formed when hot air rises off the land causing cooler sea air to fill the space left, creating a cooler breeze near the coast.

The strength of the sea breeze is directly proportional to the temperature difference between the land and the sea. Sea breezes usually occur in the afternoon.

Wind direction and surf

An on-shore wind blows towards the coast, causes waves to crumble and increase in energy.

An off-shore wind blows from the coast, keeps a wave clean and reduces energy.

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