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101 Cards in this Set
- Front
- Back
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What are some of the fields of oceanography
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Physical Oceanography
Chemical Oceanography Geological Oceanography (Marine Geology) Geophysical Oceanography (Marine Geophysics) Biological Oceanography (Marine Biology) Paleo-oceanography Ocean Engineering Ocean Remote Sensing Ocean Environment, Policy, and Planning |
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Why is oceanography an interdisciplinary science?
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It draws from many fields of study including Geology, Astronomy, Physics, Chemistry, Biology and Geography
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What is the average temperature of the ocean?
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39F (or 4C)
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What is the average salinity of the ocean?
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3.5% or 35 0/00
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What is the average depth of the ocean?
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2.5 miles
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What is the average light penetration of the ocean?
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100 meters
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What is the longest mountain range in the ocean?
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40,000 miles
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What percentage of earth's surface water does the ocean make up?
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97%
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What is the ocean's role in climate?
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-Receives more than half of the sun’s energy entering the climate system
-Low albedo and large heat capacity -Drives the hydrologic cycle -Minimizes tropical-polar temperature contrast -Air-Sea Interactions = Hurricanes, Storms, Monsoons, ENSO, etc. |
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What is the Antarctica Circumpolar current? How long is it? How much water does it carry?
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Antarctica's Circumpolar Current stretches for more than 12,400 miles around Antarctica. It carries about 135 million cubic meters of water per second - equivalent to about 135 times the flow of all the world's rivers combined
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When was the 1st systematic bathymetric survey of the ocean floor?
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Challenger expedition (1872-1876)
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When was the 1st echo sounding survey of the ocean floor?
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German ship Meteor (1920’s)
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What is SONAR?
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SONAR - Sound Navigation and Ranging
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What is single beam bathymetry?
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Single-beam provides depth information along the ship's trackline (What is directly under the ship)
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What is multi beam side scan sonar?
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Sonar that uses multiple beams of sound to record bathymetric measurements for wide swaths of sea floor
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What is satellite based Altimetry?
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Use of satellites to detect small differences in sea level which are representative of topography under ocean
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What is Geosat?
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A satellite (launched in 1985) measured the sea surface height -moving at 7 km (4 mi) per second- Measurements provided are accurate to within 0.03 m (1 inch)
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How much of the earth's surface is ocean?
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70.8%
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How much of the earth's surface is land?
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29.2%
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What is a continental margin
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The submerged outer edge of a continent
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What is an ocean basin
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The deep seafloor beyond the continental margin
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What is a passive continental margin? What are some of the features?
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A passive continental margin is any margin that is not at a subduction zone. They usually have a long continental shelf. The shelf breaks at the continental slope and you can see deep see fans. After that is the continental rise which terminates in an abyssal plain.
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What is an active continental margin? What are some of the features?
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An active continental margin is a margin at a subduction zone. The continental shelf is narrow to non-existent, dropping off quickly into the depths of the subduction trench
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Physical features of ocean basins
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Abyssal Plains
Seamounts/Guyots/ Abyssal Hills Mid-Ocean Ridges Ocean Trenches |
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The Wentworth Scale of Grain Size
for Sediments |
Scale identifying sediments by size, ranging from boulders (largest) to clay (smallest)
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Different classifications of sediment
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Terrigenous (earth), Biogenous (organic), Hydrogenous (precipitation of dissolved minerals), and Cosmogenous (from space)
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What is the main source of terrigenous sediments?
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River runoff
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Name some of the resources that are extracted from the marine environment
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Salt, Metallic Sulfides and Muds
(Zinc, Iron, Copper, Lead, Silver, Cadmium), fresh water through desalinization, oil and gas, fish |
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List the 5 unique properties of water
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-Density of ice is less than liquid water
-For its molecular weight, water’s melting and boiling points are very high -High heat of fusion and vaporization -High heat capacity -Tremendous dissolving power |
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List the properties of water created by the Hydrogen Bond
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Surface tension
Adhesion Cohesion Capillarity Viscosity Dissolving power High heat capacity |
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What is Heat Capacity or Specific Heat Capacity
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heat required to raise a unit mass of substance by one degree of temperature. For water = 1 cal
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What is Sensible Heat
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heat energy stored in a substance as a result of an increase in its temperature
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What is Latent Heat
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the heat which flows to or from a material without a change to temperature. The heat will only change the phase of the material.
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What is Heat Transport or Flux?
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Conduction/Convection/Radiation
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What is the equation for Specific Heat Capacity
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Q = cm (change in T)
Where Q equals heat added, c is specific heat, m is mass and change in T is T1-T2 |
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How is salinity measured?
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Salinity is now measured by electrical conductivity using a “practical salinity scale” equivalent to gm/kg
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What is a steady state ocean?
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The ocean is in ‘dynamic chemical equilibrium’
Ions are being added and removed from the ocean at the same rate |
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What is residence time?
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Residence time is how long dissolved materials will remain in seawater.
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What is the Principle of Constant Proportions
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Principal that states that the proportion of ions relative to each other remains constant throughout the ocean
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What contributes to the level of ocean salinity?
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Global salinity patterns are linked to rainfall and evaporation
Salinity variations are driven by precipitation, evaporation, runoff and ice freezing and melting |
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Halocline
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layer of rapidly changing salinity
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What are the main dissolved gasses in the ocean
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Nitrogen, oxygen, argon, CO2
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Biolimiting nutrients in seawater
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Nitrate (NO3-)
Phosphate (PO4--) Silicate (H2SiO4) Zinc (Zn++) Cadimum (Cd++) Iron (Fe++) Germanium (H4GeO4) |
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What contributes to the heat budget of the surface of the ocean?
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Shortwave radiation is absorbed, long wave and latent heat and sensible heat are released, heat is transferred down via diffusion and turbulence, cold water is transferred up via upwelling
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Mixed Layer
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- Top layer of ocean
- Near Homogenous Temperature, Salinity, and Density. - Thickness varies (~ 20-200 m), typically ~ 100m (~ 300 feet) |
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Seasonal differences in mixed layer
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- Summer - Strong solar heating can create strong density contrast between the surface and deeper waters = Thinner Mixed Layer
- Winter - Strong Turbulence mixes heat downward producing thicker mixed layer |
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Thermocline
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Area below the mixed layer where Temperature drops rapidly between
~ 200 to 1000 meters |
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Deep ocean temperatures
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Deep Ocean: below 1000 meters, very cold with near constant temperatures ~ 80% of the Ocean
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Sea Surface Temperature (SST) Anomalies
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- An anomaly is a departure from average SST (~ 30 yr)
- Typically 1-2oC Some SST anomalies are transient events - SST anomalies persisting for many years can be signals of regional or global climate change - SST anomalies have practical and scientific applications. |
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Common Sea Surface Temperature (SST) anomaly patterns
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- Pacific Decadal Oscillation - every 20-30 yrs
- El Nino Southern Oscillation - every 2-8 yr Atlantic Multidecadal Oscillation - Every 60 - 80 yrs - Indian Ocean Dipole - Every 1 - 4 yrs |
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Common Seasonal SeaSurface Temperature (SST) anomaly patterns
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- Strong Cooling (Anomaly) off the coast of California
During the Spring-Summer -Strong Cooling (Anomaly) in the Arabian Sea During the summer months |
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California Spring-Summer Cooling Anomaly
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During the upwelling season (March-July), strong northwest winds and the south flowing California Current drive surface waters away from the shore.
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How SST’s are Measured?
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- In-situ thermometry-based measurements using ships and buoys since 1871 AD
- Satellite based since 1980s using heat seeking sensors- radiometers (AVHRR) - Entire Earth Coverage twice a day Ground-truthing with Buoys/Ships |
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Sea Surface Salinity (SSS) Distribution
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Distribution of salinity of water throughout ocean - salinity is generally greater along the equator and in the Atlantic, Mediterranean and Indian oceans
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Key Processes of Sea Surface Salinity (SSS)
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Balance between Precipitation (P) and Evaporation (E),
Freshwater runoff; Sea-ice formation; Ocean currents |
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Average and Range of Sea Surface Salinity (SSS)
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Range ~ 32- 40 psu; average ~ 35.0; Extremes: > 42 and < 26
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Halocline
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Layer of ocean where salinity rapidly increases (high lattitudes) or decreases (low lattitudes)
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what was the Great Salinity Anomaly?
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The Great Salinity Anomaly, a large, near-surface pool of fresher-than-usual water, was tracked as it traveled in the sub-polar gyre currents from 1968 to 1982.
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What are the three processes that drive ocean circulation
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-Surface Circulation
(surface currents) -Vertical Circulation (upwelling/downwelling -Deep Ocean Circulation (Thermohaline) |
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What drives Surface Circulation
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Global Wind,
Earth’s Rotation, Continental Geometry |
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What drives Vertical Circulation
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Wind Stress,
Coastal Geometry |
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Deep Ocean Circulation
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Driven by density contrast
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Name the Warm Surface Currents
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-North Pacific Current
-Equatorial counter current (Pacific Ocean at Equator) -South Equatorial current (Indian ocean to Atlantic Ocean at Equator) -North Equatorial Current (Idian and Atlantic Ocean at Equator) -Kurisho Current (Japan) -Gulf Stream |
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Name the mixed temperature surface currents
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North Atlantic Drift
West Wind Drift (South Pacific) |
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Name the cold surface currents
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Antarctic circumpolar current
Labrador Current Falkland Current (South atlantic off coast of S. America) |
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Subtropical Gyres
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Western Boundary Currents
Eastern Boundary Currents |
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Equatorial Currents
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Westward flowing currents
Counter currents Undercurrents |
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Surface Current Systems
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Subtropical Gyres
Equatorial Currents Sub-polar Gyres Antarctic Currents |
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Major Ocean Gyres (Subtropical
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- North Atlantic Gyre
- South Pacific Gyre - South Atlantic Gyre - Indian Ocean Gyre - North Pacific Gyre |
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Wind-Stress and Ekman Effect
(Northern Hemisphere) |
Surface water travels in direction 45 degrees to the right of the wind direction
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Wind-Stress and Ekman Effect
(Southern Hemisphere) |
Surface water travels in direction 45 degrees to the left of the wind direction
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Coriolis effect on currents
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Because currents are driven by the movement of wind across the water of the ocean, the Coriolis effect (which effects wind) also affects the movement of the ocean’s currents. Many of the ocean's largest currents circulate around warm, high pressure areas called gyres. Though the circulation is not as significant as that in the air, the deflection caused by the Coriolis effect is what creates the spiraling pattern in these gyres.
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What causes gyres
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Water forms mounds via the Coriolis deflection pushing in and the pressure gradient pushing out
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What is a Sverdrup? What is is used for?
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Sverdrup (sv) is a unite
1 Sv = 1 million cubic m/second Used to measure Transport volumes in ocean |
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What is westward intensification
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An gyre that becomes elongated on the Western Side
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Equatorial Currents
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North Equatorial
Equatorial counter current South Equatorial Current |
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Antarctic Circulation/currents
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Antarctic Circumpolar Current (or West Wind Drift)
Encircles Earth Transports more water than any other current East Wind Drift from polar easterlies |
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Atlantic Ocean circulation/gyres
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North Atlantic Subtropical Gyre
Sub-Polar Gyre South Atlantic Subtropical Gyre |
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Currents that contribute to North Atlantic Subtropical Gyre
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Gulf Stream
North Atlantic Current Canary Current North Equatorial Current Atlantic Equatorial Counter |
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Currents that contribute to Sub-Polar Gyre
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Labrador Current
Irminger Current Norwegian Current North Atlantic Current |
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Currents that contribute to South Atlantic Subtropical Gyre
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South Equatorial Current
Brazil Current Benguela Current |
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Pacific Ocean circulation/gyres
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North Pacific Subtropical gyre
Sub-polar Gyre South Pacific subtropical gyre |
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Currents that contribute to North Pacific Subtropical gyre
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Kuroshio
North Pacific Current California Current North Equatorial Current |
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Currents that contribute to Sub-polar Gyre
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Alaskan Current
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Currents that contribute to South Pacific subtropical gyre
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East Australian Current
Antarctic Circumpolar Current Peru Current South Equatorial Current |
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What do temperature and salinity affect
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Density
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What do density differences in the ocean affect?
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Circulatoin
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Factors affecting temperature
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solar radiation (increase in temp)
heat loss to atmosphere (decrease in temp) |
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Factors affecting salinity
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Formation of sea ice (increase)
Evaporation (increase) Precipitation (decrease) Ice melt (decrease) River discharge (decrease) |
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Pycnocline
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Layer of ocean where there is a sharp increase in density
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What are Water Masses? What are some of the properties of water masses?
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- Waters of different densities
- Identifiable - come from different areas of the ocean - Do not mix readily - Tend to flow over and under each other for long distances |
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What is the Nomenclature of Water Masses-
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Surface 0- <1000 m depth
Intermediate 1000-2000 m depth Deep 2000-5000 m depth Bottom on the ocean bottom |
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North Atlantic Deep Water (NADW)
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Forms in the Norwegian and and Labrador Sea
Flows south, overrides AABW, mixes around Antarctica |
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Antarctic Atlantic Bottom Water (AABW)
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Densest water
Forms in the Weddell sea during southern winter ice formation Distinguishable to: ~ 45°N in the Atlantic (750 yrs) ~50°N in the Pacific (1600 yrs) |
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Antarctic Atlantic Intermediate Water (AAIW)
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Cold, relatively low salinity water mass found mostly at intermediate depths in the Southern Ocean
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Mediterranean Intermediate Water (MIW)
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(warm and very saline)
Spills from Mediterranean over the Gibraltar Sill Forms a tongue in the Atlantic ~1000m deep |
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What are the markers of O2 as a Tracer of Circulation
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"Young” water will have High dissolved O2 - Start of the conveyor- deep North Atlantic
“Old” water will have Low dissolved O2 - End of the conveyor- deep North Pacific |
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What are the markers of Nutrients as Tracer of Circulation
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"Young” water is Low in nutrients
Start of conveyor- deep North Atlantic “Old” water is High in nutrients End of conveyor- deep North Pacific |
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What causes costal upwelling?
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The coastal winds blow down the coast and the ekman effect pushes water away from coast, causing upwelling from underneath
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What causes equatorial upwelling?
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The ekman effect on the northern and southern equatorial currents push water away from the equator on each side, causing upwelling
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What drives Southern Ocean Upwelling?
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The antarctic circumpolar current travels clockwise and the East wind drift travels counter clockwise which causes upwelling right between the two currents
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