1.1.2 - Temporal variations and their influence on coastal environments Flashcards
Define the term temporal
Refers to time
What causes the tides to occur ?
Tides are caused by the gravitational pull of the moon and to a lesser extent , the sun, usually resulting in two high tides and 2 low tides
The moon pulls the water towards it , creating a high tide and there is a complementary bulge on the opposite side of the earth
At locations between the 2 bulge there will be a low tide as the moon orbits the earth the high tides follow it
What is semi diurnal tides ?
Some places like Atlantic coastline , experiences semi - diurnal tides this means they have 2 high tides and 2 low tides
What is diurnal tides ?
Antarctic receives diurnal tides which means one high & one low tide
What is the difference between spring tide and neap tide ?
Spring tides occur when the sun , moon and earth are in a straight line which happens twice each lunar month when the gravitational pull is strongest . It causes the high tide to be at its highest and the low tide to be at its lowest .
Combined gravitational-pull of the moon and the sun the tide water seem to print forward
Neap tide ( more erosion) happens during the alternative weeks in the lunar month , when the earth , moon and sun form at right angle lessening the over all gravitational pull & giving a lower tidal range
What is the tidal range and what erosional process May that cause for a cliff face ?
Tidal range is the difference in vertical height between low and high tide
Larger tidal ranges are required to produce more energy for more traditional tidal power plants - west coast of the British isle has a stronger & larger tidal range
What is micro tidal range & macro tidal range ?
Micro tidal range - has a range of less than 2m ( erosion happens more faster)
Macro tidal range has a tidal range of over 4m
Why do tidal ranges vary across the earth e.g the Mediterranean Sea ?
Tidal range can be a significant factor in the development of a coastal landscape
In enclosed seas, such as the Mediterranean Sea tidal ranges are low because wave movement is restricted to a narrow area of sea
In places where the coast is funnelled such as the seven estuary tidal range can be high as 14m ( tourist like it )
How do tidal ranges affect certain landscape?
Tidal range determines the vertical distances over which coastal processes operate .
On a micro tidal coast ( eastern Australia) wave breaking is concentrated in a narrow vertical zone throughout the tidal cycle . Erosional features such as wave cut notches are formed at the foot of the cliff
What do macro tidal coastline do ?
On a macro tidal coast ( most of the Ik coast & parts of North America ) the bay of fundy the greatest tidal range In the world) wave energy is distributed over a wide area . It’s erosional capacity is relative less less. Resulting in more dispositional features
What happens during the diurnal rise and full of tides ?
Wetting & drying of the substrate occurs . In a macro tidal environment more substrates is exposed or submerged therefore affected by processes such as Salt weathering . Sand dunes are more likely to develop in a macro tidal environment . There is a wide expanse of deposited beach . Sand which dries and can be subsequently transported landward by aelian processes.
Ebb - tide goes down
Flood - tide rises
define the term current
a large movement of water in one direction is a current
curent can be temporary or long term they can be near the surface or in the deep ocean. the largest one shape the earth glocal climate patterns and even local weather conditions by moving heat around the world
what are the types of current ?
- tidal currents
- shore normal currents
- rip currents
- longshore currents
- river currents
what do rip currents do ?
tida; currents can also move sediments where they became rip currents can be dangerous to swimmers
the dreaded rip tide deos not have anything to do with tides - rip cuurent
a rip current is a long narrow band of water that can pulldwimmers away from the the shore and to the sea in a few second
what does a flood tidal do ?4
as water rises with the tide it produces tidal currents . it floods the intertidal zone ( flood tide ) cuasing sediment to be picked up ( entrainment ) and be deposited
the falling tide (ebb tide ) carries material in the reverse direction
current velocities are low at the strat and end of each cycle and at theor max in the middel of the rising or falling tide . different sized particles are therefore entrained and depostied at different times in different locations
