Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
82 Cards in this Set
- Front
- Back
|
Thermohaline Circulation |
-Affects all of the ocean's water -Transports vast amt. of heat and salt around the oceans -Nutrients, Oxy, CO2 to deep ocean
|
|
|
Deep Water Circulation |
-Slow deep water circulation is driven by density differences and not by wind energy as surface circulation -Density is a function of (T)hermo and (H)aline -Formation and downwelling of deep water occurs in polar regions
|
|
|
Density Stratification |
-The ocean is density stratified with denser water being deeper |
|
|
North Atlantic Deep water |
-Warm salty waters carried northward in Gulf stream (gyre) -North Atlantic Current (some enters Norwegian sea) -Chilled salty water denser than polar water and sinks |
|
|
Antarctic Bottom Water |
-Densest water mass in the world -Produced near Antarctic coast during winter months -Brine formation -Migrates long distances northward |
|
|
Thermo circulation interruption |
Fear of N. Atlantic becoming too fresh to sink b/c increased sea export from Arctic ocean and the melting of the Greenland Ice Sheet adds fresh water to the system |
|
|
Wind Induced Vertical Circulation |
-Vertical movement induced by wind driven horizontal movement of water -Upwelling -Downwelling |
|
|
Upwelling |
-The upward motion of water -Brings cold nutrient rich water to surface
|
|
|
Downwelling |
-Downward motion of water -Supplies deeper water with nutrients and dissolved gasses |
|
|
Wind can induce upwelling near coasts |
In Northern hemisphere coastal upwelling can be caused by winds from the North blowing along the West coast of a continent. By Ekman transport is replaced by cold, deep, nutrient laden water |
|
|
Ekman transport |
-In Northern hemisphere ice transports clockwise -In S. hemisphere ice transports counterclockwise
|
|
|
Pycnocline |
-Nutrients can be broken down and made available again for consumption but nutrients need to be brought up to surface again -Bottom waters are usually nutrient rich b/c of accumulation of dead organisms -Can be recycled and brought to surface |
|
|
Pycnocline locations |
-At high latitudes pycnocline not developed -At the equator the pycnocline very shallow |
|
|
Southern Oscillation |
A reversal of airflow between the normally low atmospheric pressure over the Western Pacific and normally high pressure over the Eastern Pacific: the cause for El Nino |
|
|
El Nino |
Southward flowing nutrient poor current of warm water off coast of Western South America, caused by a breakdown of the trade-wind circulation |
|
|
ENSO |
-El Nino Southern Oscillation -lasts 1-3 yrs. -No upwelling -Normal circulation can return with vigor (la nina)
|
|
|
La Nina |
-Occurs at end of ENSO event -Normal tropical Pacific atmospheric and oceanic circulation strengthens and surface temperature of eastern Pacific drops below avg. -Strong upwelling
|
|
|
Effects of Upwelling |
-Nutrient rich water brought to surface -Increased biological productivity -Influences the weather (chilled temps. San Fran)
|
|
|
Effects of Downwelling |
-Supplies deep ocean with dissolved gasses -Influences distributions of organisms -No influence on weather |
|
|
El Nino and La Nina are exceptions to |
Normal wind and current flow |
|
|
Deep water circulation as opposed to surface |
-90% of ocean water is circulated below surface -slow river like masses in a few places -most volume of deep water creeps fasts |
|
|
Equitorial Upwelling |
-Associated with Intertropical convergence zone -Easterly (westward) trade winds blow from NE and SE and converge along equator blowing west -Upwelling occurs just N and S of equator causing divergence with denser nutrient rich water upwelled from below, high phytoplankton |
|
|
Coastal Upwelling |
-When Ekman transport is occurring away from coast surface waters are replaced by deeper colder denser water -Most common -Associated with human activities (fisheries) |
|
|
Antarctic Circumpolar Current |
-Moves clockwise from W to E around Antarctica -Antarctic Convergence: where cold Antarctic waters meet warm subarctic waters (creates upwelling) -High levels of phytoplankton |
|
|
Surface and thermo currents are shaped by |
-Gravity -Friction -Coriolis effect |
|
|
Circulation |
-Transports mass (ekman transport, geostrophic flow) -Affected by coriolis -Exp. Gyres |
|
|
Waves |
-Transfer energy -Not affected by coriolis -exp. stadium waves |
|
|
Ocean Waves |
-Move energy across surface across sea surface 1. orbits 2. orbital waves 3. progressive waves |
|
|
Waves: Concept |
-Waves transmit energy not water mass across ocean's surface -Because waves have no mass they are not affected by coriolis effect -Ocean waves are orbital waves in which ducks (water molecules) move in orbits (closed circles) as the waves pass |
|
|
Frequency |
Number of wave crests passing point A or point B each second |
|
|
Period |
Time required for wave crest at point A to reach point B |
|
|
Crest |
Highest Point medium rises to |
|
|
Trough |
Lowest point medium rises to |
|
|
Anatomy of progressive wave |
-orbital path extends to depth of half of wavelength -water in water column moves in uniformed circular movement as waves pass |
|
|
Behavior of waves is influenced by |
Depths of water through which they are moving -deep water: L/2 -shallow water: L/20 |
|
|
Capillary waves (ripples) |
-Disturbing force: wind -Restoring force: surface tension |
|
|
Combers or whitecaps forms if |
-waves steepness > 1:7 ratio or >120 degree angle -wind energy is dissipated as heat |
|
|
Wave Trains |
Wind waves travel in groups |
|
|
Swell |
The smooth undulation of ocean water caused by wave dispersion |
|
|
Factors that influence wind wave development |
1. Wind strength 2. Wind duration 3. Fetch
|
|
|
Wind Strength |
Wind must be moving faster than the wave crests for energy transfer to continue |
|
|
Wind Duration |
Winds that blow for a short time will not generate larger waves |
|
|
Fetch |
Uninterrupted distance over which the wind blows without significant change in direction |
|
|
Fully developed sea |
The maximum wave size possible for a wind of a specific strength, duration, and fetch |
|
|
Waves: Concept |
-Waves are created by disturbing forces -Flattened by restoring forces (wind waves, grav) -More energy is stored in wind waves than any other waves |
|
|
Interference produces |
Irregular wave motions |
|
|
Destructive interference |
Two waves that cancel each other out |
|
|
Constructive interference |
Additive interference that results in waves larger than the original waves |
|
|
Rogue Waves |
Interference results in a wave crest higher than the theoretical maximum |
|
|
Other Waves |
-Shallow-Water waves -Internal waves -Standing waves -Storm Surges -Seiches |
|
|
Refraction |
-Occurs when waves approach a shore at an angle -Wave lines usually approach at angle -Part of wave line closest to shore slows down -Part of wave line further out moves faster -Wave refracts (bends) |
|
|
Internal waves can form |
Between layers of differing densities |
|
|
Internal waves |
-Move very slowly compared to wind waves -Difference in density in the ocean is small compared to the difference in density of air and water -Generally occurs at base of pyconocline -height can be higher than height of wind waves -wavelengths can be higher .5 miles -can mix ocean waters (nutrients) -can be dangerous to submarines and oil pltforms |
|
|
Standing wave |
-Oscillates vertically with no forward movement
|
|
|
Stormsurge |
-An abrupt bulge of water driven on shore by a tropical cyclone/hurricane or frontal storm -created by low atmospheric pressure underneath the storm -Short-lived can be up to 7.5 meters high -Consists of only a crest |
|
|
Why hurricanes rotate CCW in N. hemisphere |
-Coriolis deflection -Wind direction -Pressure gradient force |
|
|
Seiche |
Rocking back and forth at a specific resonant frequently in a confined area |
|
|
Tidal Waves |
Waves generated by tides
|
|
|
Dispersion |
Waves of different wave lengths travel at different speeds
|
|
|
Wavelengths are generated by
|
Short to long/slowest to fastest -capillary waves: small disturbances -wind waves -seiches: rocking of water in enclosed spaces -seismic volcanic activity, other displacements (tsunamis) -tides: gravitational attraction |
|
|
Waves of very long wavelengths are in |
Shallow waters -less than half wavelength in depth -faster -destructive |
|
|
Waves of short wavelengths are in |
Deeper waters -more than have wavelength in depth |
|
|
Deep Water Waves |
-Depth > L/2 -Speed C=L/T C=speed,celerity,m/s L=Wavelength meter T=Time (period) seconds Longer the wavelength faster the wave
|
|
|
Shallow Water Waves |
-Depth < L/20 -Speed C=SR of gd -g=acceleration due to gravity -depth of ocean limits how fast it can travel |
|
|
Tsunami |
-Shallow water waves -affected by ocean bottom contours (refracted) |
|
|
Seismic Wavelengths |
-tsunami generated by vertical movement of earth along faults
|
|
|
Tsunami causes |
-water displacement -landslides -icebergs falling from glaciers -volcanic eruptions -asteroid impacts
|
|
|
Tsunami |
-The speed shallow water waves can travel depends on depth -in deep ocean they can travel speed of jet liners -can predict arrival time at distant shores -warning networks can save lives |
|
|
Tides |
-Longest of all ocean waves -Forced waves formed by gravity and intertia -most can be accurately predicted |
|
|
Tsunamis vs tides |
-Tsunamis: shallow, free, triggered by seismic and displacement, restoring force gravity -Tides: shallow, forced, gravitational (moon and sun, restoring force gravity |
|
|
Tides and forces that generate them |
-Formed by gravitational force of sun, moon, and motion of earth -wavelength can be half circumference of earth -forced because never free of forces that cause |
|
|
Earth-Moon system |
-Moon does not rotate around center of earth -rotate around common mass 1,000 m beneath earth's surface -Moon's gravity attracts tides towards it -Motion of earth around center mass of earth creates opposite mass (inertia/centrifugal force) -Create two tidal bulges |
|
|
Astronomical Tides |
-Sun and moon influence tides together -At new and full moons solar and lunar tides reinforce each other making spring tides: the highest high and lowest low tides -At first and third quarter moons the sun, earth, and moon form a right angle creating neap tides: the highest lows low and lowest high tides |
|
|
Conundrum one |
Oceans are not deep enough for bulges to go around Earth as deep water waves. Instead max c depends on depth of ocean |
|
|
Conundrum two |
Continents in the way that block the bulges to go around undisturbed |
|
|
Development Amphidromic Point (around running) |
a) tide wave enters ocean basin in N. hemisphere b) Wave goes right b/c of c. effect causing high tide on basin's eastern shore c)unable to keep turning right b/c of shore, crest moves n.ward following shoreline and causing high tide on basin's n.thern shore d) continues progress in basin CCW forming high tide on W. shore and completing circuit Point at which crest moves |
|
|
Semidiurnal Tide |
Occur twice in a lunar day: two high tides and two low tides of equal level
|
|
|
Diurnal Tides |
Occur once each lunar day: One high tide and one low tide |
|
|
Mixed tides |
Describe a tidal pattern of significantly different heights through the cycle |
|
|
Tidal Range |
height difference between low and high tides |
|
|
Tidal bore |
-Forms in some inlets (a true tidal wave) -flood current: tide crest -ebb current: tide trough -slack water: midway between low and high tide |
|
|
Luna |
-born in puget sound -moved to nootka sound; rugged coast of Vancouver BC -department of fisheries and oceans -mowachaht/mochalaht first nations -Killed by tug boat in 2006
|
