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206 Cards in this Set
- Front
- Back
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what causes waves?
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wind blowing over the ocean
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three factors used to classify waves?
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Distrubing force
restoring force wavelength |
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what are the 5 types of waves?
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capillary wave
wind wave seiche Tsunami (seismic sea wave) Tide |
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List the gravity waves
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Gravity waves (waves whose restoring force = gravity):
-wind waves -seiche -Tsunami -Tides |
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What is the
Disturbing force (DF) and the Restoring force (RF) and Wavelength (L) of Capilary waves? |
RF- cohesion of water molecules
DF- wind L- .68 inches |
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DF, RF, and L of wind waves
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DF- wind over the ocean... doy
RF- Gravity L- 200-500ft |
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DF, RF, and L of seiches
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DF- Change in atmospheric press
RF- Gravity L- large/variable |
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DF, RF, and L of Tsunamis
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DF- earthquake/volcanoes/landslide
RF- Gravity L-125 miles! |
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DF, RF, and L of Tides
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DF- Gravitational attration (earths rotaion)
RF- Gravity L- half of earths curcumference |
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waves transmit energy and the particles move in what kind of path?
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orbital path
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when partivesl move in orbital paths. (waves transmit evergy along interfaces between two fluids of different densities)
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orbital waves
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cyclic motion of particles
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orbital paths
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wave period (T)
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time for one wavelength to pass a fixed point
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frequency
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1/T
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calc wave steepness
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H/L
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what determines the size of the orbits in a wave?
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the wavelength
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what determines the shape of the orbits in weaves?
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water depth... orbits are only circular in deep water
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at what depth is there no perceptible motion due to waves?
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when depth = 1/2 the wavelength
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list the features of a progressive wave
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node
trough crest still water lvl btwn crest and trough direction of wave motion wavelength from crest to crest orbital path of indiv water molecs at surface |
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wave base is located at?
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1/2 L
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what is celerity (C)?
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wave speed
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Deep water waves are ________
T for deep water waves are in ? wavelength? |
aka wind waves
T in seconds wavelength less than 600 meters |
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what is the water depth for deep water waves?
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greater than the wave base (1/2 L)
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Transitional Waves:
characteristics? water depth? |
characteristics from both deep and shallow waves
water depth: less than 1/2 L more than 1/20 L Wave "feels bottom" and orbits start to flatten into ellipses |
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shallow water waves:
depth? types? T? wavelength? Characteristics? |
depth = less than 1/20 L
types = Tsunamis and tides T= in minutes! (20 mins) Wavelength = 200km! Characteristics: waves in elipses due to closeness of sea floor |
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Compare deep and shallow water waves:
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DEEP
wind waves 20 sec periods L = <600m v = 112 km/h SHALLOW seismic sea waves 20 minute periods L= <200 km v= greater than 760 km/h |
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describe how wind waves form... ready go!
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so...
-wind blows (at sea area) and forms small CAPILLARY WAVES (1/2 in in size) -Cap waves get bigger, and capture more wind, as wind is continually added (energy is added) -larger gravity waves then form -Turns to FULLY DEVELOPED SEA where max H and L are reached -as waves move from the sea area (where the waves originated) SWELLS then begin to form -larger swells (w/ larger L) move faster -waves group and separate themselves by similar L and speed.. -so Wave trains are formed -Steepness eventually reaches 1/7 ratio of height/ Wavelength -When a ration greater than 1/7 is reached, the waves will break and form white caps |
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fully developed sea
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Max H and L for those conditions
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where wind driven waves are generated
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sea or sea area
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swell definition
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uniform symmetrical waves
originate from sea area |
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factors affecting wave energy
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wind speed
wind duration fetch |
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what is fetch
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when wind blows in the same direction for over a long distance
(distance over which wind blows) |
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when waves sort themselves based on L and speed in wave trains
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wave dispersion
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Describe wave trains
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this occurs when swells sort based on similar L and speed
the leading waves dissapear while the mew waves are formed at the back |
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diff between indiv wav velocity and group velocity?
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Individual wave velocity:
proportional to wabvelength in deep water (celerity) Group velocity: speed of wave train (1/2 speed of individual wave) -due to disapearance of lead wave and formation of back wave |
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highest seas are found..
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by antarctica in the southern seas
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why do wind waves break?
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water particles at the cest are moving faster than the wave itself and the base can no longer suppport the height
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destructive interference
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thwn two waves interact and cancel eachother out
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constructiove intercerence
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also known as additive interference
when tow waves result in one larger wave (but still same 1/T and L) |
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rogue waves
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one in 7 billion waves
when the wave crest is higher than the theoretical maximum ...many times results in loss of life |
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mixed interference?
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waves coming fromm all directions.. big mess :)
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what is an internal wave?
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subsurface waves
at the junction of water layers (progressive wave over the internal wave) occurs at different densities (at pycnocline) longer L than progressive waves(surface waves) and slow |
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importance of internal waves
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mix nutrients
planktom blooms movement of submarines oil platform stability |
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detail of wave train breaking against the shore
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1. swell feels floor when water depth = < 1/2 L
2. wave crests become peaked due to wave energy being backed into less water depth 3. L shortens but T remains the same as shore is approached 4. wave approaches 1:7 ratio 5. 1:7 surpassed and wave breaks |
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Waves Approaching Shore:
-deep water waves become ____ -waves speed _______ -wavelength (L) _______ -wave height _______ -wave steepness _______ |
1. shallow water waves
2. decreases 3. decreases 4. increases 5. increases |
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the surf zone
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shallow area along coast where waves slow steepen and break
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types of breaking waves
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spilling breakers
plunging breakers surging breakers |
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spilling breakers
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gently sloping sea floor
energy extended over long dist crest slides down face of wave |
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plunging breaker
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moderately steep sea floor
evergy over shorter distance air filled tube btween creast and foot --good to surf beak violently |
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surging breaker
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steepest sea floor
energy spread over shortest dist best for body surging beak at shore |
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wave refraction
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slowing and bending of waves in shallow water (when waves approach shore at angle)
-line doesnt break simultaneously -along irregular shoreline --headlands --waves feel bottom in shallows off the headlands |
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wave diffraction
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propagation around an obstacle
-wave can still move around obstance but wave energy is broken up |
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wave reflection
what does this cause? |
when waves bounce back from an obstacle
-creates a standing wave (seiche) |
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seiche
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water rocking back and forth at a specific resonant frequency in a confined area like a bay or lake
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there is no motion at what part of a wave?
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node
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What are Tsunamis caused by?
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the rapid displacement of ocean water
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Originates from sudden sea floor topography changes
Earthquakes – most common cause Underwater landslides Underwater volcano collapse Underwater volcanic eruption Meteorite impact – splash waves |
Tsunamis
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meteorites cause what kinds of waves
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splash waves
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these are undetected by boates in the ocean (encompasses the entire water column)
fast in open ocean -speed proportional to water depth |
Tsunamis
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December 26, 2004
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Intian Ocean Tsunami
-rupture along plate junction -raise of sea surface above -wave moved outward -waves reached pacific and atlantic coasts of N and S America! |
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PTWC
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Pacific Tsunami Warning Center
created 1948 response to tsunami in Hawaii 1946 |
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use seismic waves for forecasting
use pressure sensors on the deep ocean floor relays info to buoys satellite transmission of data Dart program |
tsunami warning networks
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DART program
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Deep-ocean Assessment and Reporting of Tsunamis
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two types of currents
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surface currents
deep currents (thermohaline) |
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surface currents are driven by
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wind
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deep currents are driven by
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density
(thermohaline) |
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methods of measuring surface currents
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DIRECT METHODS
track floating devices fixed current meter INDIRECT METHODS pressure gradients radar altimeters doppler flow meter |
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method of measuring deep currents
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floating devices
-argo |
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thermohaline currents are _____ driven
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density
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surface currents flow _______
and are driven mainly by _____ |
flow horizontally
are driven by wind friction |
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surface currents are driven by wind which is driven by...
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uneven solar heating
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gyre
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large curcular pattern of water circulation
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forces that contribute to gyres
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gravity
coriolis effect solar energy solar winds |
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how are gyres formed?
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wind blows over surface of water and the water veers to the right
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the theoretical net flow of water
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the ekman spiral
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ekman spiral
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describes speed and direction of seawater flow at different depths
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what is ekman transport?
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averave movement of seawater b/c of wind influence
-deeper layers move slower -energy lost due to fruction |
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ekman transport in the N hem
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direction = 90 degrees to the right of wind force
...in nature it tends to be about 70 degrees though :) |
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why will water travel to the right and contune clockwise?
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because coriolis interacts with a pressure gradient
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in geostraphic flow, water forms a ____ in a subtropical gyre
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hill
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geostraphic flow:
coriolis effect continues to pull water to the right (up the hill) while gravity pushes water down the hill... so? |
water must go straight!
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what is the balance of coriolis effect and gravitational foces
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geostophic flow
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___________ generates actual geostrophic flow
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friction
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________ is strongest at the poles and nonexistent at the equator
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coriolis effect
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western boundary current
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gulf stream
narrow and deep with warm water |
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eastern boundary current
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canary current
shallow and wide with cold water |
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how many geostrophic gyres are there?
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5:
turtle gyre heyerdahl gyre columbus gyre navigator gyre majid gyre |
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subtropical geostrophic gyres are in balance between....
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pressure gradient and coriolis effect
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6th type of current?
-flows endlessly eastward driven by powerful westerly winds |
west wind drift/
antarctic circumpolar current -not a geostrophic gyre |
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types of subtropical gyres
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1. western boundary currents
2. eastern boundary currents 3. equatorial current 4. northern/southern boundary currents |
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Each gyre contains how many boundary currents
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4 interconnecting currents
-diff flow and temp |
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West boundary currents
-major characteristics |
narrow deep and fast
moves warm water poleward |
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largest western boundary current
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gulf stream
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meanders (eddies) form where?
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western boundary
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describe what meanders/eddys do
direction of cores? |
pinch off and become isolated cells
warm cores go clockwise cold cores go counterclockwise |
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eastern boundary current
-major characteristics |
cold shallow and broad
carry water to the equator eddies tend not to form |
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W or E boundary current?
canary current, benguela current, california current |
eastern boundary current
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W or E boundary current?
narrow: less than 100 Km |
Western boundary current
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W or E boundary current?
slow and shallow |
eastern boundary current
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W or E boundary current?
-waters derived from low latitudes and are warm... little or no upwelling |
western boundary current
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W or E boundary current?
-waters derived from middle lattutudes and are cool...coastal upwelling common |
eastern boundary current
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these currents flow from east to west and west to east
what currents are these and what do they result from? |
transverse currents result from stress of trade winds on ocean
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surface currents affect....
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weather and climate
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Currents in the north atlantic
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North atlantic current (going E)
canary current (going S) North equatorial current (going W) gulf stream (going N) |
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Westward intensification
(effect on gyres) |
with coriolis effect the center of geostophic hill os offset to the west
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upwelling
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upward motion of water
-cold nutrient rich water towards the surface |
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downwelling
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downward motion of water
-supplies the deeper ocean with dissolved gasses |
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this kind of wind-induced vertical circulation can be induced both at the equator and at coasts
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upwelling
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is upwelling or downwelling good for fishing?
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upwelling
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two types of upwelling
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coastal and equatorial
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ENSO
el nino southern oscillation |
when the walker cell circulation is distrupted
high pressure in eastern pacific weakens |
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when this occurs, trade winds diminish and then reverse and there is an eastward movement of warm water
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el nino
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surface water in cent and east pacific ocean become warmer
-storms over land inc |
el nino
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consequences of el nino
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collapse of fisheries
nutrient upwelling fails plankton decline fish starve |
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what happens with thermocline in el nino
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deepends in eastern pacific
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there are weaker trade winds in el nino years or non el nino years
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el nino years
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weather of el nino
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wet, cool in south
warm, dry in North |
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in ______, low atmospheric pressure allows storms to move towards the west
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el nino
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deep ocean currents are driven by...
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temp and density diff in water
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different water masses in deep ocean currents
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surface water
central water intermediate water deep water bottom water |
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formation of antarctic bottom water
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ice forms and frigid brine squeezes out and sinks to the bottom spreading along the deep sea bed
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formation of atlantic deep water
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forms in N polar ocean
topography prevents most of its escape cold winds from N canada cool the warm salty N atlantic ocean water releases heat and sinks Heat warms europe |
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cycle of rising and sinking air due to heating and cooling air
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convection cell
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air flows from ________ to _____ pressure
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high to low
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the observed deflection of moving objects
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CORIOLIS EFFECT
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what causes the coriolis effect
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moving frame of reference on the spinning earth
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coriolis effect has the greatest effect on....
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objects that move long distances across latitudes
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doldrums
-location? -atmospheric press? -Characteristics? |
this is a boundary zone
equatorial low pressure light winds, cloudy and rainy, hurricanes! |
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horse latitudes
-location? -atmospheric press? -characteristics? |
this is boundary
30degrees high pressure light wind, dry and clear, a little precip, major deserts of the world |
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Polar Front
-location? -atmos pressure -characteristics |
this is a boundary
60 degrees low pressure ariable winds, stormy, cloudy all year |
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poles
-location? -atmos pressure -characteristics |
90 degrees (this is a boundary)
high pressure variable winds cear dry, cold temp, minimal precip, cold deserts |
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trade winds
-location -Characteristics |
this is a wind belt
5-30 degrees strong steady winds from east |
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prevailing westerlies
-location -Characteristics |
this is a wind belt
30-60 deg winds from west, bring storms that influence weather across US |
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polar easterlies
-location -Characteristics |
this is a wind belt
60-90 deg cold, dry winds from east |
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saffir simpson scale
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measure huricane intensity based on wind speed an damage
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category 5 hurricane
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155 mi/hr winds
surges 19 feet high catastrophic damage -entire building failures -shrubs,trees,signs blown down, -flooding of lower floors of structures |
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category 1 hurricane
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74-95 mi/hr winds
surges 4-5 feet miniman damage to buildings |
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category 3 hurricane
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111-130 mi/hr winds
surges 9-12 feet Extensive damage -some structure damage -foliage blown off trees |
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96-110 mi/hr winds
6-8feet surges damage = moderate -some roofing door window damage and some trees |
category 2
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131-155 mi/hr winds
13-18 feet surges extreme damage -more extensice structure damage and wall failures -most shrubs and signs blown down |
category 4 hurricane
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in reality, the three cell model is much more complex due to....
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seasonal changes
distrib of continent and ocean diff in heat capacity btwn continents and ocean -monsoon winds |
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polar easterlies
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60-90 degrees
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prevailing westerlies
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surface winds of ferrel cells
30-60 degrees |
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trade winds
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surface winds of hadley cells
subtropical highs to equator |
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3 winds w/ in circulation cells
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trade winds
prevailing westerlies polar easterlies |
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within circulation cells, winds named for...
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where they come from
-3 types |
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how does air move w/in curculation cells?
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rapidly from high to low press
-stron dependable winds |
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3 boundaries of curculation cells
-air moves vertically -weak erratic surface winds |
1 doldrums of intertropical convergence zone (equator)
2 horse latitudes 30deg 3 polar fronts 60 |
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low pressure zones
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rising air
equatorial low subpolar lows- 60deg overcast skies with much precip |
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high pressure zones
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decending air in circulation
subtropical highs- 30deg polar highs 90deg clear skies |
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what is an atmospheric circulation cell?
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a large circut of air
-earth has 3 in each hemisphere |
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What is an atmospheric circulation cell?
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a large circut of air
-earth has 3 in each hemisphere |
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3 cells exist in each hemisphere
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0-30 hadley cells
30-60 ferrel cells 60-90 polar cells |
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explain the movement of air from the equator to poles due to cor effect
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air rises at equator
moves to poles not straight path deflected eastward -right in N hem -left in S hem |
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coriolis effect has greatest effect on objects that move long distances across
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latitudes
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cor effect at equator? poles?
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zero at equator
greatest at poles |
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b/c of cor effect, objects in the S hem are deflected to the
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left
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what is the coriolis effect?
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deflection of moving air/water away from its initial course cause by earths eastward rotation
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globas curulation of air is governed by what two factors?
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uneven solar heating
earths rotation |
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describe atmospheric circulation
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convection cell
hot air rises and travels till cooles and comes down |
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what influences air density
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temp and water
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which is less dense
humid or dry air? (at same temp) |
humid air
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what does cold air do as it cools and sinks
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condenses
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why is warm air less dense than cold air
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more molecular movement
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what is the troposphere?
composition? |
earths lower atmosphere
78% nitrogen 20% oxygen nearly homogenious mixture 7 miles |
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residence of air
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10 days
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like the layers of the atmosphere in order
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top
exoshere thermosphere mesosphere stratosphere troposphere bottom |
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as you move up in the stratosphere.... temp....
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temp increases
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as you move up in the troposphere... temp...
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decreases
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layer where all weather occurs
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troposphere
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extra-tropical cyclones
where form? |
form BETWEEn air masses
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causes of hurricanes
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powered ny latent heat of vaporization
originates from low pressure cells |
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hurricane characteristics
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1. move westward with trade winds
2. they either die over land or turn eastward 3. they lose power over the cooler ocean of mid latutudes |
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features of a hurricane
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wind
rain storm surge -causes water to lift up -biggest cause to destruction |
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most active hurricane season recorded
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2005
water so much warmer -28 tropical cyclones -15 became hurricanes -3 were category 5! more than 1800 lost lives/ 1.5 million displanced |
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NOAA predictions
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said this season has 70% chance of above-norm activity
predicted hurricanes would -reach peak activity early in life cycle -retained energy for long periods -SST were high in GOM and west atlantic |
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hurricane katrina
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most costly natural disaster
-went tru miami at cat 1 -entered gulf of mx ---over warm water ---cat 5 ---went over cold ---cat 4 |
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_____ and _____ caused great loss of life and prop during hurriane catrina
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storm surge and low central pressure
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hur katrina affected
1. gulf port and Biolx,ms 2. bay st louis 3. new orleans |
1. Gp and B: all homes and business destroyed
2. storm surge 34ft high 3. New O.- levees failed city flooded |
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Hurricane rita
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less than 1 month after katrina
warm G.O.M. cat 3 broke through New O levees |
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hurricane wilma
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most powerful atlantic huric ON RECORD
hit mex at cat 4 then FL at cat 3 |
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coastal alteration causes
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result of hurricanes
-barrier islands move |
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over time hurricanes are...
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increasing in intensity
about 90 a year -hasnt changed -but inc in ocean temp inc intensity |
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Ocean climate zones
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EQUATORIAL
rising air, weak winds, doldrums TROPICAL extend to top of cancer and cap strong wind,little precip,rough seas SUBTRIPICAL high press, decending air, weak wind TEMPERATE strong W wind, severe storms SUBPOLAR extensive precip, summer sea ice POLAR high pressure, sea ice most of the year |
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sea ice formation
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indiv ice crystals
then become larger- into slush then become pancake ice then pancakes for ice floes rate depends on temp self perpetruation cause this causes more cooling |
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large sheets of ice over land and water are called
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glaciers
-icebergs break off of glaciers -calvina |
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wind power produced by
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wind turbines and offshore wind farms
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2 types of ocean currents
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surface currents
-wind driven deep currents -thrmohaline -density driven |
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mass flow of ocean water
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ocean currents
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how to measure deep currents
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cemical tracers
temp and salinity protiles -floating devices are called argos |
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subtropical gyres
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large curcular pattern of water circulation
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forces that contribute to gyres
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gravity
coriolis effect solar energ solar winds |
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what are cyclones? two types?
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storms with rotaring masses of low pressure are with torrential rain
tropical and extra tropical |
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warm air blown on top of retreating edge of cold air = ?
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warm front
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when cold air advances and causes a lifting of air mass
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cold front
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fronts
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boundaries between air masses
-area where storms develop |
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may cause unusual weather
-streering air masses/ weather masses |
jet streams
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-large volumes of air with distinct props
-uniform temp humidity and density -take on characteristics of surface below |
air masses
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storms
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distrurbances in atmospheric ciculation
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land heats ______ than ocean in the spring
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faster
-intensity and location of monsoon activ depends onb the position of the ITCZ |
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monsoon wind pattern
...linked to ? |
seasonal patterns of wind curculation
-dry winters and wet summers linked to -diff btwn heat of land and water -N-S movement of ITCZ |
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differential solar heating is due to
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heat capacities of land and water
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cyclonic flow
directions of rotaiton |
around a low
countercl in N Hem clockwise in S hem |
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moves n and s depending on the season
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ITCZ
meteoroligical equator hadley cells follow this |
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on the meteorological equator... atmosphereis and oceanic curculation in hems are...
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symmetrical
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weather vs climate
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weather
conditions of atmosphere at a PARTICULAR time and place climate LONG TERM average of weather |
