Coastal Systems and Landscapes - A Level AQA Geography

Atmosphere

The air that surrounds the earth

Lithosphere

A rigid layer made up of the uppermost part of the mantle and the crust.

Hydrosphere

All the water on earth

Biosphere

The part of Earth where life exists

Isolated system

A system that can exchange neither energy nor matter with its surroundings.

Closed system

There is input, transfer and output of energy but NOT matter.

Open system

Inputs and outputs of both energy and matter

Input

Energy/matter entering a system

Output

Energy and/or matter leaving a system

Store/component

A section of a system in which matter can remain, be added to or removed from

Flow/transfer

Movements between stores/components within a system

Boundary

The edge of a system

Dynamic Equilibrium

When the inputs and outputs of a system are balanced and stores remain the same

Negative feedback

When a system acts by lessening the effect of the original change and ultimately reversing it

Positive feedback

When a change in a system is further amplified, causing a snowball effect

Inputs to the Coastal System

-Energy from waves, wind, tides and sea currents
-Sediment
-Geology of coastline
-Sea level change

Components of the Coastal System

-Erosional landforms and landscapes
-Depositional landforms and landscapes

Outputs of the Coastal System

-Dissipation of wave energy
-Accumulation of sediment above tidal limit
-Sediment removed beyond local sediment cells

Marine Factors

Waves, winds, tides, salt spray and currents

Subaerial Factors

Temperatures and weather

Human factors

Pollution, management, buildings, recreation

Tectonic Factors

Coastal uplift, volcanic activity

Geological Factors

Structure and lithology

Biotic Factors

Vegetation, coral reefs etc.

Climatic Factors

Winds, weather, climate change, glaciation

Geomorphic Factors

Rivers, glaciers, mass movement

Wind Map North to South

Easterlies, Westerlies, Horse Latitudes, NE Trade Winds, Doldrums, SE Trade Winds, Horse Latitudes, Westerlies, Easterlies

How are waves formed?

Wind blows over the surface of the water, creating drag and gaining grip, with the friction causing disturbance and forming waves as a result. Circular to elliptical orbit, crest of wave rises and steepens, breaks.

How does fetch influence waves?

Makes the waves more powerful, increases wave energy

Wave Crest

Highest point of a wave

Wave Trough

Lowest point of a wave

Wave Height

the vertical distance from the crest of a wave to the trough

Wavelength/Amplitude

The distance between two corresponding parts of a wave

Wave Period

the time required for one cycle

Wave frequency

The number of waves passing a fixed point per second.

Swell waves

Waves in open water, characterised by long wavelengths and reduced height. Travel long distances, up to 15m

Storm Waves

Large waves generated by strong winds that travel short distances

Constructive Waves

The swash is stronger than the backwash therefore the material is moved up the beach and much is left there.

Destructive Waves

The backwash is stronger than the swash therefore material is dragged back down the beach and moved along the coast.

Zones of a Coastline

Wave refraction

Slowing and bending of progressive waves in shallow water - concentrate on headlands, negative feedback

Spring tides

tides that have the greatest tidal range due to the alignment of the earth-moon-sun system.

Neap tides

tides with minimum daily tidal range that occur during the first and third quarters of the moon.

Tidal range

The difference in levels of ocean water at high tide and low tide

Macro tidal

Tidal range of more than 4m

Meso tidal

Tidal range between 2 m and 4 m.

Micro tidal

Tidal range less than 2m

Storm surges

A wall of water that is pushed ashore by a storm. Low pressure raises sea levels, winds push high sea towards coast

Longshore currents

movement of water near & parallel to shore

Rip currents

Narrow streams of water that break through sand bars and drain rapidly back to sea

Upwelling

the upward movement of ocean water toward the surface as a result of diverging currents