PHS 1010- Ch. 15-unit 4

Ocean currents

Masses of water that flows from one place to another

Surface currents

Develop from friction between the ocean and the wind that blows across the surface

Gyres (+ location of each)

Huge, slowly moving surface currents (5 major ones)

1. North pacific gyre

2. South Pacific gyre

3. North Atlantic gyre

4. South Atlantic gyre

5. Indian Ocean gyre

Coriolis effect

The surface circulation of currents are deflected by the spinning of the earth

• Currents are deflected to the right in the Northern Hemisphere

• Currents are deflected to the left in the Southern Hemisphere

Thermohaline circulation

Ocean currents due to differences in density due to temperature and salinity

Shore

Area between lowest tidal level and highest areas affected by storm waves

Shoreline

Contact between land and sea

Coastline

The seaward edge of the coast

Beach

Accumulation of sediment along the landward margin of the ocean.

Crest

Top of the wave

Trough

Bottom of the wave

Wave height

The vertical distance between a trough and a crest

Wavelength

The horizontal distance between successive crests(or troughs)

Wave period

The time it takes for one full wave to occur

Wave base

The lowest level of movement within a wave.

Fetch

The distance that the wind travels

Beach drift

Sediment moves in a zigzag pattern along the beach face due to waves moving onto the shore at an angle but gravity moving it straight out- result of longshore currents

Longshore currents

Current in surf zone that flows parallel to the shore

Wave refraction

bending of a wave

Headland

Land that sticks can't into the sea (or heads out)

Wave-cut cliff

Cliff eroded by waves

Wave-cut platform

Flat area (horizontal) along a shore cut by wave erosion

Marine terrace

When the platform is no longer under water

Sea stack

When the arch has eroded away leaving rock detached from the rock shore

Sea arch

Rocks make an arch; created as the headland is eroded more from the sides

Spit

A ridge of sand extending from the land into the mouth of an adjacent bay with an end that often hooks landward; the direction of the rock is the direction of the current

Baymouth bar

A sand bar that completely crosses away; can have river exits through it

Tombolo

A ridge of sand that connects an island to the mainland

Barrier island

A ridge of sand parallel to the shore but offshore (not connected to it)

Seawall

Armors the coast against the force of breaking waves

Groin

Barriers built at a right angle to the beach that are designed to trap sand

Breakwater

Barriers built offshore and parallel to the coast to protect boats from breaking waves

Beach nourishment

Adding sand to the beach system ( responses to erosion problems/alt. to hard stabilization)

Ch. 15 - Psalms 33:7

He gathered the water of the sea into a heap. He made the great ocean stay in its place.