Key Words Flashcards
System
a set of interrelated components working together towards some kind of process
system attribute
the perceived characteristic of a system element.
e.g. number, size, colour, volume and temperature
system boundary
outer edge of system. Zone between one system and another.
system element
the kinds of things or substances composing the system. They may be atoms or molecules, or larger bodies of matter-sand grains, rain drops, plants or cows.
system relationship
the association that exists between the elements and attributes of a system based on cause and effect.
system state
current value of a system’s elements, attributes and/or relationships.
isolated system
a system that has no interactions beyond its boundary layer. Many controlled lab experiments are of this type.
closed system
a system that transfers energy, but not matter, across its boundary to the surrounding environment. Our planet is often viewed as a closed system.
open system
a system that transfer both matter and energy across its boundary to the surrounding environment.
input
addition of matter, energy or information to a system.
output
movement of matter, energy or information out of a system.
store
matter, energy or information is stored.
transfer
when something is moved from one place to another
landform
a natural feature of the earth’s surface
erosion
the gradual destruction of the earth’s surface
transportation
when materials are moved by the force of something else
deposition
when materials are deposited on the earth’s surface
hydrosphere
all the water on the earth’s surface
lithosphere
the crust and upper mantle
atmosphere
the gas that surrounds the earth
cryosphere
frozen water on the earth’s surface
biosphere
the region of the earth occupied by living things
hard engineering
man-made structures used to defend against natural hazards
soft-engineering
using natures existing systems to defend against natural hazards
eustatic change
sea level change
isostatic change
land level change
backshore
lying between the foreshore and coastline. dry under normal conditions bar extreme weather.
backwash
the return of water to the sea after waves break on a beach
beach
a deposit of sand or shingle at the coast
coastal zone
the interface between land and sea.
constructive waves
they deposit sand on the beach. Strong swash and weak backwash.
destructive waves
they erode and carry sediment away from the beach. Weak swash and strong backwash.
Fetch
the maximum distance of water over which winds can act upon a wave before being interrupted by land.
Foreshore
part of the beach which is wet under normal conditions due to varying tide and wave run-up.
near shore zone
extending seaward from the low water line until well beyond the breaker zone
low water line
the minimum extent the tide reaches at low tide
high water line
the maximum extent the tide reaches at high tide
offshore zone
beyond the nearshore zone (further seaward)
littoral zone
extends seaward from the nearshore zone to beyond the breaker zone. Where the littoral (shoreline) processes take place - like longshore drift.
shoreline
intersection between the mean high water line and the shore.
swash
forward movement of a wave up a beach.
positive feedback
where a flow/ transfer leads to increase or growth
negative feedback
where a flow/transfer leads to decrease or decline
dynamic equilibrium
this represents a state of balance within a constantly changing system
sediment cell
a distinct area of coastline separated from other areas by well defined boundaries, such as headland and stretches of deep water.
physical weathering
the disintegration of rocks as a result of weather processes.
chemical weathering
the decomposition of rocks due to a chemical reaction
biological weathering
the breakup of rocks due to flora and fauna
beach profile
a cross section of a beach
strata
a layer of sedimentary rock or soil with internally consistent characteristics that distinguish it from other layers
bedding planes
a line in rocks separating two different
joints
small cracks in the layers of rock created during earth movements
faults
a large crack in the rock caused by earthquake movements
folds
a type of earth movement resulting from the horizontal compression of rock layers by internal forces of the earth along plate boundaries
relief
refers to the highest and lowest elevation points in an area
lithoseres
where plants colonise bare rocks
hydroseres
where plants colonise aquatic areas
haloseres
where plants colonise salt marshes and sea estuaries
psammosere
where plants colonise coastal sand areas
Name some inputs into the coastal system:
river discharge precipitation wind and wave energy tidal system atmospheric conditions human action
name some stores of the coastal system
beach
spit/bar/tombolo
name some transfer processes in the coastal system
longshore drift
erosion
deposition
transportation
name some outputs of the coastal system
landforms habitats e.g mudflats salt marshes habitable land beaches
how do waves form and progress?
1) wind tugs at the surface of the water causing a wave shape to move
2) when a wave moves into the shallow water near the coast, it is distorted until it ‘breaks’
3) friction occurs between the base of the wave and the seabed
4) the water rushes forward onto the beach.
what are the features of a constructive wave
low wave height long wave length powerful swash weak backwash low angle of attack
builds gentler beach profiles
what are the features of a destructive wave
high wave height short wave length weak swash powerful backwash steep angle of attack
builds steep beaches.
what are currents caused by?
temperature differences
salinity differences
wind speed differences
size of fetch
What is a rip-current?
How are they formed?
a current flowing back out towards deeper ocean. Rip currents can form in a gap between sandbars, piers, or parts of a reef. Such underwater obstacles block waves from washing directly back to sea. The water from these waves, called feeder waves, runs along the shore until it finds an opening around the obstacle. The water rushes through the opening and turns into a rip current, flowing much faster than the water around it and through the line of breaking waves. The rip current pulls anything stuck in it out to sea, although it will later dissolves as deeper water is reached.
What is a rip-current?
How are they formed?
a current flowing back out towards deeper ocean. Rip currents can form in a gap between sandbars, piers, or parts of a reef. Such underwater obstacles block waves from washing directly back to sea. The water from these waves, called feeder waves, runs along the shore until it finds an opening around the obstacle. The water rushes through the opening and turns into a rip current, flowing much faster than the water around it and through the line of breaking waves. The rip current pulls anything stuck in it out to sea, although it will later dissolves as deeper water is reached.
what is a longshore current?
How are they formed?
A longshore currents is an ocean current that moves parallel to the shore. It is caused by swells sweeping onto the shoreline at an angle and pushing water down the length of the beach in one direction.
What happens as a longshore current approaches the shoreline?
As a wave moves toward the beach, different segments of the wave encounter the beach before others, which slows these segments down.
- As a result, the wave tends to bend and conform to the general shape of the coastline.
- When a wave reaches a beach or coastline, it releases a burst of energy that generates a current, which runs parallel to the shoreline. This type of current is called a “longshore current.”
how can longshore currents shape a coastline?
It changes the slopes of beaches and creates long, narrow shoals of land called spits, that extend out from shore. The sediment is transported in the currents.
-Has the ability to create or destroy entire “barrier islands” along a shoreline.
how do upwelling currents form?
- Wind blows across surface, pushes water away.
2. Water rises up from beneath surface to replace the displaced water.
how can upwelling currents slow down the formation of a hurricane?
tropical storms generate energy from warm surface water. If the surface water is cold then the storm will not be able to gain energy.
The water cycle
A non stop cycle in which water evaporated from the sea, falls as rain and returns to the sea in rivers.
Precipitation
Transfer of water from the atmosphere to the ground. It can take the form of rain, snow, hail, dew.
Evaporation
Transfer of water from a liquid state to a gaseous state.
Condensation
Transfer of water from a gaseous state to a liquid state (water vapour).
