Beaches Exam 1 Flashcards
Is there a global-scale organization of the Earth’s surface that controls the gneeral nature of the coasts?
Yes, theory of plate tectonic.
Can we put the world’s continents together like pieces of jigsaw puzzles?
Yes, Wegener did it in 1912.
What is the top layer?
The top rigid layer is the Crust, made of granite and basaltic rocks
What is the middle layer?
The mantle includes the second and third rigid layer and a plastic layer sandwiched in between the two. It’s made of silicate materials
What is the bottom?
The core made of iron with nickel and sulfur. Two parts the outer core is molten and the in layer is rigid.
What are the six layers of earth by physical properties?
Ocean, Lithosphere:First (crust) and second (part of mantle) rigid layer, Asthenosphere: plastic layer, Mesosphere: third rigid layer, Outer core: molten and Inner core: rigid.
Is the ocean crust more or less dense than the continental crust?
More dense at 2.9, than the crust of 2.7
What evidence supports the plate techonic theory?
1) Global distribution of seismis activities
2) Magnetic stripes caused by normal and reverse polar magnetism recorded inthe crust symmetrically on both sides of the oceanic ridges.
3) The youngest crust lies closest to the oceanic ridge and consistant aging of the ridge in both directions.
How is new sea floor made?
New sea floor is formed at the mid-ocean ridge and subducted back into the mantle at the subduction zone.
What is the order of life of an ocean?
1) uplifting and rifting - african lake baikal
2) spreading-red sea
3) continued spreading
4) continued spreading and formation of subduction zone
5) subduction-atlantic and pacific
6) Collision-med sea
7) Suturing-himalayas
What is first order?
Large geographic distances, thousands of kilometers or more.
ex. entire coast and the relationship to plate boundaries
WHat is second order?
Distances of tens to hundreds of kilometers
ex.outer banks and mississippi delta, influenced by smaller scale factors.
What is third scale?
a few kileometers in length. Affected by short term processes that last for years to decades, may be controlled by local conditions. ex. beaches and inlets along Pinellas
What is the continental margin?
It is includes the continental shelf 100+m, slope (very steep or gradual) and rise leads to abysal plain
Where is the leading edge of the continent?
It is along subduction boundaries.
What is a subduction zone?
It is where the oceanic lithosphere and astenosphere are subducted under the continental lithosphere.
Where is the marginal sea coast?
Protected by volcanic island arc boundaries, behave like trailing edge, may have large deltas, smaller waves. ex.between Japan and asia
Where is the trailing edge of the continent?
It is on the side of the continent with a spreading center. ex. atlantic
What charcterizes a leading coast?
Steep continental shelf, mountains ranges, large waves, submarine canyons and no large deltas. ex.Pacific
What characterizes a trailing edge coast?
gradual continental shelf, stable plates, small deltas
What affects weather conditions and coastal environments?
The oceans.
What makes the weather?
Water vapor. only 0-4% of atmosphere, but is very important
What are the major gases in the environment in order of importance.
Nitrogen, oxygen
What is small scale weather?
Tornadoes-minutes affects 1 km, thunderstorms-hours affects 10 km, fronts- hours to days affects 10+km
What is large scale weather?
Synoptic cyclones-months 10^3, monsoons-months, el nino-years 10^4
What is global weather?
Climate change
Where does hot air rises?
equator (tropics) and 60 (temperate)
Where does cold air fall?
30 (hot deserts) and poles (cold deserts)
where are the tradewind and westerlies?
tradewinds blow from the east at 30 to the west at the equator.
westerlies blow from the west at 30 to the east at 60
What is meterology?
The study of atmospheric phenomena and their spatial and temporal behavior
Does water play a dynamic role in the atmosphere?
Yes, because it can change phases
WHy are carbon dioxide and ozone important?
Radiative processes
What is radiation?
the study of energy transfer or heat exchange - conservation of energy
What is thermodynamics?
The initial and final equilibrium states produced by energy processes or transformation
What is dynamics or hydrodynamics?
the study of motion of fluids in relation to force. conservation of momentum, energy and mass.
What is coastal meteorology?
the study of atmospheric phenomena occuring in the coastal zone
What is synpotic meteorlogy?
the use of meteorology data obtained instantly over a wide spread picture to present an comprehensive and instantaneous picture of the atmosphere
what is air mass?
A wide spread body of air
What makes air move?
density. Dry, cold air is densier, than warm moist air. Dense to least, cP, mP, cT, mT.
What is the Coriolis effect?
It is the effect of an object in the air above the earth does not move at the same speed as earth. this deflects object to the right in the northern hemisphere and the left in the southern
What direction do cyclones turn?
counterclockwise
What direction do anticyclones turn?
clockwise
What is a cold front?
Cold air displaces warm air mass causing heavy rain, wind and thunderstorms. bring cooler weather behind front. More significant in winter
What is a warm front?
Warm air displaces cold air mass causing broad rain
What is a cold occlusion?
THe coldest air is behind the cold front
What is a warm occlusion?
The cold air is in front of the warm front
What direction do cold fronts move?
Generally from NW to SE
How is sand affected by a cold front?
It moves it from the north to the south.
What is a tropical storm?
A cyclone that forms over a tropical ocean. move westward in the easterlies and drift poleward
How does the temperature of the water affect the air pressure?
Warmer water makes the air lighter which makes the pressure low as it rises.
What are the favorable conditions of a tropical storm?
1) SST higher than 26C
2) below normal pressure in low latitudes and above normal pressure in high latitudes.
3) existing tropical disturbance
4) movement less than 13 knots
5) decreasing wind speed with height, but updrafts
6) special dynamic conditions in air flow around 40,000ft
7) Heavy rain in the area
Characteristics of a hurricane
- Stays over warm water it strengthens
- moves over land it weakens
- moves fast north it weakens
How many times has Tampa been hit by a Cat 5?
0
What are the Cat of a hurricane?
1-74-95, 2-96-110, 3-111-130, 4-131-155, 5-155+
What causes land/sea breezes?
temperature differences
What happens in FL?
coast circulation brings air from sea to cool coastal residences in the afternoon
What is upwelling?
It is when the upper surface water is pushed away from shore and cold nutrient rich water replaces it. As the wind blows down the shore, forces work at a 90 angle pushing the water at a 45.
What is advection fog?
when warm air moves over cold water. this cools the air releasing water to fog.
What is fog?
many tiny water droplets suspended in the atmosphere close to earth.
What is the wave amplitude?
It is the distance of the wave from the crest to still wave level
What is wavelength?
The distance of the wave from crest to crest
What is wave steepness?
The ratio of the wave height to wave length
What is wave height?
The distance from trough to crest
What is wave direction?
The direction the wave is coming from, just like wind
What is frequency?
The number of waves that pass a fixed point per second.
WHat scale are waves?
small scale
What is the wave period?
The time between crest to crest
What makes waves?
Most common -Wind
Other ways - less comon- earthquakes, tsunami, landslides
How do you calculate wave speed (c)?
c= sq root of g(gravity) x h(water depth)
What happens to the orbital motion of a wave particle with depth?
The diameter and velocity of the orbital motion decrease with depth and flattens toward seabed.
How are waves measured?
Temproal domain- measure water level at high frequency
Spatial domain-picture of the ocean surface with waves
How do we analyze waves?
Spectral analyzes-analyzing the distribution as a function of frequency
Zero crossing analysis-determining measurements as it crosses zero.
What is significant wave height?
1/3 the height of the highest wave record
What is a swell?
A wave generated at a long distance away. Have long wavelength and period
What is seas?
A local wave, with short wave length and period
What is important to wind generation?
wind duration, speed and fetch (size of body of water)
What is Wave refraction?
waves bend as they enter shallow water. waves travel faster in deeper water.
Waves converge on penisulas and diverge on canyons.
What is wave diffraction?
wave energy is transferred laterally along the wave
What is wave reflection?
standing waves form from reflected waves. Waves can increase i size if not reflected correctly.
Out of phase-cancels, in phase builds
What is wave shoaling?
Decreases wave velocity and length, but increase height, but period remains the same.
What is wave breaking?
when a wave becomes unstable and spills over the top.
What factors have the most influence on wave breaking?
- beach slope
- ratio of water depth at breaking and wavelength of breaking waves
- Ratio of breaking wave height and deep water wave length
- ratio of deep water height and wave length
What happens when waves break?
waves transfer energy through breaking. Turbulence is created, energy is transfered,wave energy is transfered to move sand, changing the coastal environment, once all energy is lost the ocean ends
What are the 4 forms?
Spilling breakers-small steepness, gradual build then collapses as white water
Plunging breakers-large steepness, builds vertically, then the top falls and comes down as one mass of water
Surging Breakers-base hits the shore first causing the wave to collapse
Collapsing breakers-combo of plunging and surging
When do waves break near shore?
when the height of the wave is .78 times the water depth
What is tide?
regular rising and falling of the water level
What is semi-diurnal?
2 high and 2 low tides each day
What is full diurnal?
1 high and 1 low tide each day
What is tidal range?
vertical distance between successive high and low
What is tidal period?
the time between one high or low and the next high or low
What is high water?
the max water level reached during a tidal cycle
What low water?
the min water level reached during a tidal cycle
What is flood current?
water movement toward the shore
What is ebb current?
water movement away from shore
What is spring tide?
tides of large range that occur every 14 days
What is neap tide?
tides of small range that occur every 14 days
WHat is slack water?
no movement in or out of water, speed is zero
What is mean high or low water?
The mean high/low water averaged over 19 years
What is higher/lower high/low water?
the average of the higher/lower high/low water level of each day averaged over National TIdal Datum Epoch(19 years)
WHat is neap range?
the average of mean high water neap and low water neap.
WHat is mean range?
the average of mean high water and low water.
What is spring range?
the average of mean high water spring and low water spring.
