Oceanography Midterm

Front 1

What are some of the fields of oceanography

Back 1

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

Front 2

Why is oceanography an interdisciplinary science?

Back 2

It draws from many fields of study including Geology, Astronomy, Physics, Chemistry, Biology and Geography

Front 3

What is the average temperature of the ocean?

Back 3

39F (or 4C)

Front 4

What is the average salinity of the ocean?

Back 4

3.5% or 35 0/00

Front 5

What is the average depth of the ocean?

Back 5

2.5 miles

Front 6

What is the average light penetration of the ocean?

Back 6

100 meters

Front 7

What is the longest mountain range in the ocean?

Back 7

40,000 miles

Front 8

What percentage of earth's surface water does the ocean make up?

Back 8

97%

Front 9

What is the ocean's role in climate?

Back 9

-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.

Front 10

What is the Antarctica Circumpolar current? How long is it? How much water does it carry?

Back 10

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

Front 11

When was the 1st systematic bathymetric survey of the ocean floor?

Back 11

Challenger expedition (1872-1876)

Front 12

When was the 1st echo sounding survey of the ocean floor?

Back 12

German ship Meteor (1920’s)

Front 13

What is SONAR?

Back 13

SONAR - Sound Navigation and Ranging

Front 14

What is single beam bathymetry?

Back 14

Single-beam provides depth information along the ship's trackline (What is directly under the ship)

Front 15

What is multi beam side scan sonar?

Back 15

Sonar that uses multiple beams of sound to record bathymetric measurements for wide swaths of sea floor

Front 16

What is satellite based Altimetry?

Back 16

Use of satellites to detect small differences in sea level which are representative of topography under ocean

Front 17

What is Geosat?

Back 17

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)

Front 18

How much of the earth's surface is ocean?

Back 18

70.8%

Front 19

How much of the earth's surface is land?

Back 19

29.2%

Front 20

What is a continental margin

Back 20

The submerged outer edge of a continent

Front 21

What is an ocean basin

Back 21

The deep seafloor beyond the continental margin

Front 22

What is a passive continental margin? What are some of the features?

Back 22

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.

Front 23

What is an active continental margin? What are some of the features?

Back 23

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

Front 24

Physical features of ocean basins

Back 24

Abyssal Plains
Seamounts/Guyots/ Abyssal Hills
Mid-Ocean Ridges
Ocean Trenches

Front 25

The Wentworth Scale of Grain Size
for Sediments

Back 25

Scale identifying sediments by size, ranging from boulders (largest) to clay (smallest)

Front 26

Different classifications of sediment

Back 26

Terrigenous (earth), Biogenous (organic), Hydrogenous (precipitation of dissolved minerals), and Cosmogenous (from space)

Front 27

What is the main source of terrigenous sediments?

Back 27

River runoff

Front 28

Name some of the resources that are extracted from the marine environment

Back 28

Salt, Metallic Sulfides and Muds
(Zinc, Iron, Copper, Lead, Silver, Cadmium), fresh water through desalinization, oil and gas, fish

Front 29

List the 5 unique properties of water

Back 29

-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

Front 30

List the properties of water created by the Hydrogen Bond

Back 30

Surface tension
Adhesion
Cohesion
Capillarity
Viscosity
Dissolving power
High heat capacity

Front 31

What is Heat Capacity or Specific Heat Capacity

Back 31

heat required to raise a unit mass of substance by one degree of temperature. For water = 1 cal

Front 32

What is Sensible Heat

Back 32

heat energy stored in a substance as a result of an increase in its temperature

Front 33

What is Latent Heat

Back 33

the heat which flows to or from a material without a change to temperature. The heat will only change the phase of the material.

Front 34

What is Heat Transport or Flux?

Back 34

Conduction/Convection/Radiation

Front 35

What is the equation for Specific Heat Capacity

Back 35

Q = cm (change in T)

Where Q equals heat added, c is specific heat, m is mass and change in T is T1-T2

Front 36

How is salinity measured?

Back 36

Salinity is now measured by electrical conductivity using a “practical salinity scale” equivalent to gm/kg

Front 37

What is a steady state ocean?

Back 37

The ocean is in ‘dynamic chemical equilibrium’

Ions are being added
and removed from the ocean at the same rate

Front 38

What is residence time?

Back 38

Residence time is how long dissolved materials will remain in seawater.

Front 39

What is the Principle of Constant Proportions

Back 39

Principal that states that the proportion of ions relative to each other remains constant throughout the ocean

Front 40

What contributes to the level of ocean salinity?

Back 40

Global salinity patterns are linked to rainfall and evaporation

Salinity variations are driven by precipitation, evaporation, runoff and ice freezing and melting

Front 41

Halocline

Back 41

layer of rapidly changing salinity

Front 42

What are the main dissolved gasses in the ocean

Back 42

Nitrogen, oxygen, argon, CO2

Front 43

Biolimiting nutrients in seawater

Back 43

Nitrate (NO3-)
Phosphate (PO4--)
Silicate (H2SiO4)
Zinc (Zn++)
Cadimum (Cd++)
Iron (Fe++)
Germanium (H4GeO4)

Front 44

What contributes to the heat budget of the surface of the ocean?

Back 44

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

Front 45

Mixed Layer

Back 45

- Top layer of ocean
- Near Homogenous Temperature, Salinity, and Density.
- Thickness varies (~ 20-200 m), typically ~ 100m (~ 300 feet)

Front 46

Seasonal differences in mixed layer

Back 46

- 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

Front 47

Thermocline

Back 47

Area below the mixed layer where Temperature drops rapidly between
~ 200 to 1000 meters

Front 48

Deep ocean temperatures

Back 48

Deep Ocean: below 1000 meters, very cold with near constant temperatures ~ 80% of the Ocean

Front 49

Sea Surface Temperature (SST) Anomalies

Back 49

- 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.

Front 50

Common Sea Surface Temperature (SST) anomaly patterns

Back 50

- 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

Front 51

Common Seasonal SeaSurface Temperature (SST) anomaly patterns

Back 51

- Strong Cooling (Anomaly) off the coast of California
During the Spring-Summer
-Strong Cooling (Anomaly) in the Arabian Sea
During the summer months

Front 52

California Spring-Summer Cooling Anomaly

Back 52

During the upwelling season (March-July), strong northwest winds and the south flowing California Current drive surface waters away from the shore.

Front 53

How SST’s are Measured?

Back 53

- 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

Front 54

Sea Surface Salinity (SSS) Distribution

Back 54

Distribution of salinity of water throughout ocean - salinity is generally greater along the equator and in the Atlantic, Mediterranean and Indian oceans

Front 55

Key Processes of Sea Surface Salinity (SSS)

Back 55

Balance between Precipitation (P) and Evaporation (E),
Freshwater runoff; Sea-ice formation; Ocean currents

Front 56

Average and Range of Sea Surface Salinity (SSS)

Back 56

Range ~ 32- 40 psu; average ~ 35.0; Extremes: > 42 and < 26

Front 57

Halocline

Back 57

Layer of ocean where salinity rapidly increases (high lattitudes) or decreases (low lattitudes)

Front 58

what was the Great Salinity Anomaly?

Back 58

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.

Front 59

What are the three processes that drive ocean circulation

Back 59

-Surface Circulation
(surface currents)
-Vertical Circulation
(upwelling/downwelling
-Deep Ocean Circulation
(Thermohaline)

Front 60

What drives Surface Circulation

Back 60

Global Wind,
Earth’s Rotation, Continental
Geometry

Front 61

What drives Vertical Circulation

Back 61

Wind Stress,
Coastal Geometry

Front 62

Deep Ocean Circulation

Back 62

Driven by density contrast

Front 63

Name the Warm Surface Currents

Back 63

-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

Front 64

Name the mixed temperature surface currents

Back 64

North Atlantic Drift
West Wind Drift (South Pacific)

Front 65

Name the cold surface currents

Back 65

Antarctic circumpolar current
Labrador Current
Falkland Current (South atlantic off coast of S. America)

Front 66

Subtropical Gyres

Back 66

Western Boundary Currents
Eastern Boundary Currents

Front 67

Equatorial Currents

Back 67

Westward flowing currents
Counter currents
Undercurrents

Front 68

Surface Current Systems

Back 68

Subtropical Gyres
Equatorial Currents
Sub-polar Gyres
Antarctic Currents

Front 69

Major Ocean Gyres (Subtropical

Back 69

- North Atlantic Gyre
- South Pacific Gyre
- South Atlantic Gyre
- Indian Ocean Gyre
- North Pacific Gyre

Front 70

Wind-Stress and Ekman Effect
(Northern Hemisphere)

Back 70

Surface water travels in direction 45 degrees to the right of the wind direction

Front 71

Wind-Stress and Ekman Effect
(Southern Hemisphere)

Back 71

Surface water travels in direction 45 degrees to the left of the wind direction

Front 72

Coriolis effect on currents

Back 72

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.

Front 73

What causes gyres

Back 73

Water forms mounds via the Coriolis deflection pushing in and the pressure gradient pushing out

Front 74

What is a Sverdrup? What is is used for?

Back 74

Sverdrup (sv) is a unite
1 Sv = 1 million cubic m/second
Used to measure Transport volumes in ocean

Front 75

What is westward intensification

Back 75

An gyre that becomes elongated on the Western Side

Front 76

Equatorial Currents

Back 76

North Equatorial
Equatorial counter current
South Equatorial Current

Front 77

Antarctic Circulation/currents

Back 77

Antarctic Circumpolar Current (or West Wind Drift)
Encircles Earth
Transports more water than any other current
East Wind Drift from polar easterlies

Front 78

Atlantic Ocean circulation/gyres

Back 78

North Atlantic Subtropical Gyre
Sub-Polar Gyre
South Atlantic Subtropical Gyre

Front 79

Currents that contribute to North Atlantic Subtropical Gyre

Back 79

Gulf Stream
North Atlantic Current
Canary Current
North Equatorial Current
Atlantic Equatorial Counter

Front 80

Currents that contribute to Sub-Polar Gyre

Back 80

Labrador Current
Irminger Current
Norwegian Current
North Atlantic Current

Front 81

Currents that contribute to South Atlantic Subtropical Gyre

Back 81

South Equatorial Current
Brazil Current
Benguela Current

Front 82

Pacific Ocean circulation/gyres

Back 82

North Pacific Subtropical gyre
Sub-polar Gyre
South Pacific subtropical gyre

Front 83

Currents that contribute to North Pacific Subtropical gyre

Back 83

Kuroshio
North Pacific Current
California Current
North Equatorial Current

Front 84

Currents that contribute to Sub-polar Gyre

Back 84

Alaskan Current

Front 85

Currents that contribute to South Pacific subtropical gyre

Back 85

East Australian Current
Antarctic Circumpolar Current
Peru Current
South Equatorial Current

Front 86

What do temperature and salinity affect

Back 86

Density

Front 87

What do density differences in the ocean affect?

Back 87

Circulatoin

Front 88

Factors affecting temperature

Back 88

solar radiation (increase in temp)
heat loss to atmosphere (decrease in temp)

Front 89

Factors affecting salinity

Back 89

Formation of sea ice (increase)
Evaporation (increase)
Precipitation (decrease)
Ice melt (decrease)
River discharge (decrease)

Front 90

Pycnocline

Back 90

Layer of ocean where there is a sharp increase in density

Front 91

What are Water Masses? What are some of the properties of water masses?

Back 91

- 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

Front 92

What is the Nomenclature of Water Masses-

Back 92

Surface 0- <1000 m depth
Intermediate 1000-2000 m depth
Deep 2000-5000 m depth
Bottom on the ocean bottom

Front 93

North Atlantic Deep Water (NADW)

Back 93

Forms in the Norwegian and and Labrador Sea
Flows south, overrides AABW, mixes around Antarctica

Front 94

Antarctic Atlantic Bottom Water (AABW)

Back 94

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)

Front 95

Antarctic Atlantic Intermediate Water (AAIW)

Back 95

Cold, relatively low salinity water mass found mostly at intermediate depths in the Southern Ocean

Front 96

Mediterranean Intermediate Water (MIW)

Back 96

(warm and very saline)
Spills from Mediterranean over the Gibraltar Sill
Forms a tongue in the Atlantic ~1000m deep

Front 97

What are the markers of O2 as a Tracer of Circulation

Back 97

"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

Front 98

What are the markers of Nutrients as Tracer of Circulation

Back 98

"Young” water is Low in nutrients
Start of conveyor- deep North Atlantic

“Old” water is High in nutrients
End of conveyor- deep North Pacific

Front 99

What causes costal upwelling?

Back 99

The coastal winds blow down the coast and the ekman effect pushes water away from coast, causing upwelling from underneath

Front 100

What causes equatorial upwelling?

Back 100

The ekman effect on the northern and southern equatorial currents push water away from the equator on each side, causing upwelling

Front 101

What drives Southern Ocean Upwelling?

Back 101

The antarctic circumpolar current travels clockwise and the East wind drift travels counter clockwise which causes upwelling right between the two currents