Deck 6: Ocean Circulation

Question 1

A sverdrup (sv) is a measure of .

A) wind speed
B) current speed and direction
C) the volume of water transported in an ocean current
D) the amount of heat transferred to water from the sun

Answer 1

C

Question 2

Earth's rotation influences currents by a "force" known as .

A) an Ekman spiral
B) geostrophism
C) the gyre counter rotation
D) the Coriolis effect

Answer 2

D

Question 3

The only ocean current that continues in an uninterrupted circle around the circumference of Earth without encountering land is the .

A) Gulf Stream
B) Kuroshio, or Japan, Current
C) Antarctic Circumpolar Current
D) Canary Current

Answer 3

C

Question 4

A system of ocean currents that circulate around the periphery of an ocean basin due to the forces of surface winds, the sun's heat, the Coriolis effect, and gravity is called .

A) a cell
B) a gyre
C) a microscale current
D) convection cells

Question 5

Generally, the fastest and deepest ocean currents are .

A) northern boundary currents
B) eastern boundary currents
C) western boundary currents
D) southern boundary currents

Question 6

Currents tend to move in large patterns in the Northern Hemisphere.

A) irregular
B) counterclockwise
C) clockwise
D) random

Question 7

The mass flow of ocean water that is driven by wind or gravity is referred to as ocean .

A) waves
B) ENSO events
C) currents
D) tides

Question 8

Which statement about geostrophic gyres is true?

A) One of the six gyres is the Antarctic Circumpolar Current.
B) Gyres are influenced by the Coriolis effect and the position of continental landmasses.
C) Gyres are formed by deep water currents that flow in a continuous circuit around the five major basins.
D) Sea level is lower in the middle of the gyre.

Question 9

Which of the following statements is true about an Ekman spiral?

A) The net flow of a wind-driven surface current in the Northern Hemisphere will flow at about a 50 ° angle to the wind.
B) With increasing depth, each layer will move faster than the overlying layer of water.
C) Because of Ekman transport, at some frictional depth, water will be moving in the opposite direction from the surface current.
D) An Ekman spiral is not influenced by the Coriolis effect.

Question 10

Which of the following is an eastern boundary current?

A) Canary Current
B) Kuroshio Current
C) Gulf Stream
D) North Equatorial Current

Question 11

England's weather is than would be expected at that latitude because of the influence of surface currents.

A) colder
B) drier
C) less humid
D) warmer and wetter

Question 12

Which ocean surface current transports the greatest volume of water?

A) The Kuroshio (or Japan) Current
B) The North Equatorial Current in the Pacific
C) The South Equatorial Current in the Pacific
D) The Antarctic Circumpolar Current

Question 13

A transverse current is a .

A) bottom current flowing in the same direction as an overlying surface current
B) surface current that connects eastern-boundary and western-boundary currents
C) cold surface current that flows from the poles toward the equator
D) theoretical current not yet discovered

Question 14

The largest of the western boundary currents is the .

A) Gulf Stream
B) California Current
C) East Pacific Gyre
D) Canary Current

Question 15

San Francisco's characteristic cold and foggy weather during the summer is caused by a .

A) cold eastern boundary current
B) warm eastern boundary current
C) cold western boundary current
D) warm western boundary current

Question 16

The primary force responsible for surface currents is .

A) precipitation
B) wind
C) heat
D) gravity

Question 17

Which of these is commonly an effect of El Niño?

A) A decline in the exotic species of fish and other forms of marine life in the affected waters
B) A decrease in ocean surface temperature in the eastern Pacific
C) A decrease in rainfall in west coastal countries or states of the American continents
D) An often catastrophic decrease in the commercial fisheries in Peru

Question 18

Coastal upwelling is most common in association with in the Northern Hemisphere.

A) western boundary currents
B) eastern boundary currents
C) transverse currents
D) northern boundary currents

Question 19

One source of dissolved gases and nutrients to deep waters is .

A) downwelling
B) upwelling
C) conduction
D) Langmuir Circulation

Question 20

The Canary Current is an example of a .

A) shallow, cold water current
B) deep, cold water current
C) warm, southerly current
D) mesopelagic current

Question 21

The main force driving thermohaline circulation is .

A) wind
B) the Coriolis effect
C) density
D) electromagnetic attraction

Question 22

The Gulf Stream is a current that runs south along the eastern coast of the United States.

Question 23

Antarctic Bottom Water flows water in surface currents.

A) about the same speed as
B) slightly faster than
C) much faster than
D) much slower than

Question 24

Upwelling areas are .

A) only found near the equator
B) usually nutrient poor
C) sometimes depleted of nutrients during El Niño years
D) not affected by Ekman transport

Question 25

Upwelling has no influence on weather.

Question 26

Thermohaline circulation is a phenomenon.

A) small-scale
B) global
C) local
D) coastal

Question 27

Oceanographers name water masses according to their relative position. In temperate and tropical latitudes, there are common water masses.

A) three
B) four
C) five
D) six

Question 28

Surface winds normally move across most of the tropical Pacific in a(n) direction.

A) northeast
B) west to east
C) east to west
D) northwest

Question 29

Surface water extends to a depth of about .

A) 1,000 meters
B) 600 meters
C) 200 meters
D) 50 meters

Question 30

Ocean gyres are asymmetrical because of the Coriolis effect.

Question 31

Which statement is true with regard to thermohaline circulation?

A) Thermohaline circulation is caused by even and steady global heating of the ocean.
B) Thermohaline circulation is the result of heating of the ocean at high latitudes and cooling at low latitudes.
C) Thermohaline circulation is driven by density gradients.
D) Thermohaline circulation is primarily driven by wind.

Question 32

The North Atlantic gyre is composed of the Gulf Stream, the North Atlantic Current, the Canary Current, and the North Equatorial Current.

Question 33

Equatorial upwelling occurs in westward-flowing equatorial surface currents.

Question 34

El Niño results due to an interruption of flow of the Current in the Pacific.

A) Kuroshio
B) Equatorial
C) Canary
D) Antarctic Circumpolar

Question 35

Thermohaline circulation is responsible for large-scale movements of ocean water and depends on both the salinity and the temperature of water.

Question 36

Geostrophic currents are primarily wind driven.

Question 37

Transverse currents can flow eastward or westward.

Question 38

The densest water in ocean currents is the .

A) warmest and saltiest
B) coldest and saltiest
C) warmest and freshest
D) coldest and freshest

Question 39

One example of horizontal water movement is called downwelling.

Question 40

The Kuroshio Current is an example of an eastern boundary current.

Question 41

During a non- El Niño  year, along the west coast of Central and South America.

A) upwelling of cold water occurs
B) the air and surface water flow eastward
C) the thermocline lowers
D) higher-than-normal rainfall

Question 42

What two factors contribute to the density of water?

A) temperature and salinity
B) temperature and pressure
C) pressure and depth
D) salinity and pressure

Question 43

Scotland, Ireland has a maritime climate, warmed in part by the energy of tropical sunlight transported to high latitudes by the .

A) California Current
B) Canary Current
C) North Equatorial Current
D) Gulf Stream

Question 44

Describe the two primary forces that set ocean water in motion and how they drive both surface and thermohaline currents.

Question 45

Surface currents are traced using a(n) .

A) echo sounder
B) Argo system
C) drift bottles
D) chemical tracer

Question 46

During an ENSO event, in the eastern Pacific.

A) atmospheric pressures increase
B) water temperatures stay the same
C) water temperatures decrease
D) water temperatures increase

Question 47

Upwelling along the coast of California .

A) reduces the temperature of the local coastal climate
B) reduces biological productivity
C) increases the temperature of the local coastal climate
D) is produced by north-flowing winds

Question 48

Describe how ocean currents affect the global distribution of heat and give an example of how they moderate climate.

Question 49

Thermohaline circulation can be studied using .

A) echo sounding machines
B) chemical tracers
C) drift bottles
D) satellite images

Question 50

The is a vast sampling network of nearly 4,000 independently drifting sensors.

A) Argo system
B) chemical tracer
C) drift bottles
D) echo sounders

Question 51

Gyres move in a clockwise rotation in the Northern Hemisphere delivering surface currents along the East Coast and surface currents along the West Coast of continents.

A) warm; cool
B) cool; warm
C) warm; warm
D) cool; cool

Question 52

Antarctic Bottom Waters are the densest in the world, and characterized by temperatures and salinities than surface waters.

A) lower; higher
B) higher; lower
C) higher; higher
D) lower; lower

Question 53

What is upwelling and why is it important for biological productivity?

Question 54

The strong El Niño  of 2015 - 2016 generated significant impacts in many areas of the world. Southern California produced record global sea surface temperatures resulting in .

A) more winter rain
B) many uncharacteristic marine visitors, such as hammerhead sharks
C) cooler-than-normal atmospheric temperatures
D) a disappearance of marine organisms along the shoreline

Question 55

How do scientists study currents?

Question 56

Which occurrence will produce upwelling near coasts?

A) wind blowing toward the north along the West Coast of North America
B) wind blowing toward the south along the West Coast of North America
C) wind blowing toward the south along the East Coast of North America
D) wind blowing toward the north along the East Coast of South America

Question 57

North-flowing winds along the West Coast of North America produce , which has no direct effect on climate or productivity.

A) upwelling
B) diverging currents
C) downwelling
D) converging currents

Question 58

When an ENSO event occurs, warm equatorial waters flow in the equatorial Pacific.

A) east
B) west
C) north
D) south

Question 59

What would explain the poor condition for biological productivity in the open tropical ocean?

A) Converging currents produce downwelling, thus carrying nutrients to the deep ocean.
B) Gyres contain pollution and decaying organisms that use up available nutrients.
C) Upwelling delivers seafloor sediment to the surface, thus blocking necessary sunlight for photosynthesis.
D) Strong layering isolates deep, nutrient-rich water from the sunlit ocean surface.

Question 60

What is ENSO?

Question 61

If surface winds are blowing from the south toward the north in the Northern Hemisphere, which way will surface currents travel? Describe the Ekman spiral to answer the net movement of water.

Question 62

Describe how wind can induce upwelling and downwelling near coastal cities? Give an example for each.

Question 63

Surface currents have a significant influence on Earth's temperature, climate, and biological productivity, but thermohaline currents do not.

Question 64

Drift bottles are useful in determining coastal circulation by tracking the path of surface currents.

Question 65

Summer months in San Francisco, California are cool, foggy, and mild.

Question 66

During a non-El Niño year, trade winds blow from the normally high-pressure area over the eastern Pacific (near Central and South America) to the normally stable low-pressure area over the western Pacific (north of Australia).

Question 67

Water masses have distinct and often unique characteristics. What are the five common water masses in temperate and tropical latitudes?

Question 68

An ENSO will deliver warm equatorial waters to the western Pacific around Christmastime.

Question 69

If San Francisco, California and Washington D.C. lie nearly on the same line of latitude, then why is San Francisco cool, foggy, and mild during the summer months and Washington D.C is hot and humid?

Question 70

Why do gyres flow clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere?