Coasts Flashcards
what is a system?
a process or collection of processes that transform inputs into outputs.
define: elements
attributes
relationships
elements-parts that make up a system
attributes-characteristics of the elements
relationships-associations that occur between elements and attributes
what is an open system?
a system in which both mass and energy are allowed to transfer across the system boundary. There may also be a flow of matter in or out of the system
what is a closed system?
may be a flow of energy in or out of the system but no matter flow takes place across the system boundary(fixed with mass)
what is a isolated system?
no interaction between the system and its surroundings(its theoretical)
define input.
material or energy moving into the system from outside e.g. geology
define output.
material or energy moving from the system to the outside e.g. evaporation
define energy.
power or driving force e.g. wind
define stores/components.
parts of a system e.g. beach, sea
define flows/transfers.
the links or relationships between the components e.g. wind/water transport
define positive feedback.
where a flow /transfer leads to increase or growth e.g. constructive waves build up beach
define negative feedback.
where a flow/transfer leads to a decrease or decline e.g. erosional processes
define dynamic equilibrium.
the state of balance within a constantly changing system e.g. sediment, types of waves
what is a costal system?
a series of linked elements affecting the coastal zone through which energy and material circulate.
what is a sediment budget?
the net sum value between quantities of input and output of sediment in a system excess=positive budget deficit=negative budget no difference=neutral budget
what is a sediment cell?
a section of coastline where sediment is recycled
what is a sediment sink?
sediment is lost to the system by transfer to a location beyond further access
what is dynamism?
the degree of change taking place in a system in terms of scale and/or rate
what is the backshore?
the area between the high water mark(HWM) and the landward limit of marine activity. Changes normally take place her only during storm activity.
what is the foreshore?
the area lying between the HWM and the LWM.(most important area for marine processes in times that are not influenced by storm activity)
what is the nearshore (aka inshore)?
area between LWM and the point where waves cease to have any influence beneath them
what is the offshore?
the area beyond the point where waves cease to impact upon the seabed and in which activity is limited to deposition of sediment
what is prevailing wind?
wind that consistently blows from the same direction and generates more high energy waves thank condition where the wind direction is constantly changing
what is fetch?
the distance the wind has been blowing over a body of water. greater fetch=greater wave energy
what is abrasion?
where the waves uses material it carries to wear away landscape features
what are orbital waves?
waves that occur in the open sea as there is little horizontal movement of water
what are elliptical motions?
occurs when water becomes shallower and the circular orbit of the water particles changes to an elliptical shapes
characteristics of destructive waves.
- high, plunging waves +short wavelength
- weak swash strong backwash
- beach loss
- beach has steeper beach profile ,over time flattens
characteristics of constructive waves.
- low surging waves = long wavelength
- strong swash, weak backwash
- beach gain
- gentle beach profile, buildup over time
what is wave refraction?
when waves approach a coastline that is not a regular shape they are refracted and become increasingly parallel to the coastline
where are rocky coasts generally found?
high- energy environments
what are high- energy environments?
-places where rate of erosion exceeds rate of deposition e.g. headlands, cliffs, wave cut platforms
where are sandy coasts generally found?
in low-energy environments
what are low-energy environments
where the rate of deposition exceeds the rate of erosion e.g. beaches, spits
what are tides?
tides are caused by the effect of gravity from the moon and to a lesser extent the sun, as tide rises and falls so does sediment it carries
define spring tide.
earth, moon and sun align at a full moon and new moon and gravity of both combine create higher high tides and lower low tides
define neap tide.
when moon is at first/last quarter and sun and moon pulling at right angles to each other which creates lower high tides and higher low tides
define ocean currents.
the continuous predictable directional movement of seawater driven by gravity, wind ,water and density. Horizontal movements=currents vertical movements=upwellings/downwellings.