OCE1001 Exam 2 Chapters 7/8

Waves from separate sea areas move away as swell and produce an interference pattern when they come together. If Sea A and Sea B have wave heights of 3 meters, what would be the height of waves resulting from destructive interference?

0 meters

You live on an island in the Pacific. An earthquake of magnitude 8.5 off the coast of Japan, 8000 km away, generates a tsunami with a wavelength of 200 km. The average water depth between your island and Japan is 4900 m. If a tsunami warning is issued for your island, how many hours will you have before the waves arrive?

10.14 hours

In the open ocean, 1 wave in ________ will be three times as high as the height of the wave average.

1175

What is the speed in meters per second of a deep water wave with a wavelength of 3.5 meters?

2.34 seconds

In the open ocean, 1 wave in ________ will be over twice the height of the wave average.

23

At what Beaufort number do whitecaps begin forming?

3

Waves from separate sea areas move away as swell and produce an interference pattern when they come together. If Sea A has wave heights of 2 meters and Sea B has wave heights of 5 meters, what would be the height of waves resulting from destructive interference?

3 meters

Waves from separate sea areas move away as swell and produce an interference pattern when they come together. If Sea A has wave heights of 1.5 meters and Sea B has wave heights of 3.5 meters, what would be the height of waves resulting from constructive interference?

5 meters

At what Beaufort number do well-marked streaks of foam begin to form on the ocean surface?

7

At what Beaufort number does the sea surface begin to roll?

9

What percentage of an icebergs mass is below the waterline?

90%

What results when two waves, in phase and with the same wavelength, interact?

A wave with an amplitude that is the sum of the amplitudes of the initial two waves.

Rogue waves are created along the "Wild Coast" off the southeast coast of ________, where the Agulhas Current flows directly against large Antarctic storm waves.

Africa

Western intensification causes:

All the above effects are the result of western intensification.

Which of the following is the only current that completely circumscribes Earth?

Antarctic Circumpolar

Which of the following currents contributes to the South Western United States being arid?

California Current

Which of the following is true for downwelling?

Carries dissolved oxygen to the deep-sea floor

The California Current is an example of which of the following types of currents?

Eastern Boundary Current

The world's two main iceberg-producing regions are ________.

Greenland; Antarctica

Which of the following currents contributes to the South Eastern United States being humid?

Gulf Stream

Which swift-flowing surface current in a major subtropical gyre transports a large volume of warm water from the equator toward the mid-latitudes?

Kuroshio Current`

The North Atlantic Current is an example of which of the following types of currents?

Northern Boundary Current

The West Wind Drift is an example of which of the following types of currents?

Southern Boundary Current

The deepest and densest water mass in the world ocean is formed in the __________________.

Southern Ocean

The observation of a hill of water within all subtropical gyres is an example of which of the following?

Subtropical convergence

Why does wave height increase as waves enter shallow water?

The energy of the wave must be contained within a smaller water column in shallow

Why do ocean waves bend around headlands?

The waves are moving more slowly just in front of the headland, causing the waves to bend.

________ waves also known as side-to-side waves.

Transverse

What depth does Argo floats collect data?

Upper 2,000 meters

What does the term "in phase" refer to?

Waves in phase have identical wavelengths and are aligned peak-to-peak and trough-to-trough

The Agulhas Current is an example of which of the following types of currents?

Western Boundary Current

Which of the following generates most ocean waves?

Wind blowing across the surface

Peru's residents are familiar with ENSO as it brings a warm current that reduces populations of which animal?

anchovies

Judge the following sentence according to the criteria given below: Board surfers tend to avoid plunging breakers BECAUSE they break right at the shoreline.

both the assertion and the reason are incorrect

Judge the following sentence according to the criteria given below: The circular orbit of wave motion returns the floating object to its exact original position BECAUSE the half orbit in the trough is at the same velocity as the crest half of the orbit.

both the assertion and the reason are incorrect

What shape is formed by a parcel of water when a wave passes through it?

circle

Which conditions in the ocean promote high productivity?

cold; high nutrient

Downwelling can result from __________.

converging surface currents

What does DART stand for?

deep ocean assessment and reporting of tsunamis

Deep ocean currents are primarily driven by

density differences

What is the wavelength?

distance between crests

Of the following locations, where would upwelling be expected to occur?

diverging surface currents; seamounts or tablemounts; sharp bend in coastline

Which method would be most appropriate for directly measuring the flow rate of the Gulf Stream?

drift bottles

The area in the enclosed rectangle in the false-color map of sea surface temperatures is an example of which of the following features?

eddies

The majority of tsunami are caused by underwater ________

fault movement

During winter months, monsoon winds over the Indian Ocean ________.

flow from land to sea and are dry

Which of the following best describes a plunging breaker?

forms on moderately sloped shorelines to create curling

Of the following conditions, which is/are related to strong El Niño events?

higher sea levels; increased abundance; increase in sea-surface temperatures

For a deep-water wave, when the period increases, wavelength ____ and speed ____.

increases; increases

Of the following gyres, which one(s) flow in a counterclockwise direction?

indian; south pacific; northern hemisphere; south atlantic

Tidal movement, turbidity currents, wind stress, and even passing ships at the surface create ________ waves.

internal

Deep-water currents move ________ volumes of water and are much ________ than surface currents.

larger; slower

Which of the following is the least frequent cause of a tsunami in recent centuries?

meteorite impacts

What is a typical tsunami wavelength?

more than 200km

Ocean surface currents transfer about ________ of the total amount of heat from the tropics to the poles.

one-third

Which type of breaker has a curling crest that moves over an air pocket?

plunging

Of the following methods, which are indirect methods for measuring currents

pressure gradients; dynamic topography; doppler flow meter

Which of the following is a direct method for measuring surface currents?

propeller flow meter

Which of the following methods are used to measure ocean surface currents directly?

radio-transmitting float bottles

Records indicate that the ocean is warming faster in the Arctic polar regions than elsewhere. If that continues, a possible consequence could be __________.

slowing of deep ocean circulation

If a surfer wishes to have a really long ride, what type of wave should he or she look for?

spilling breakers

Which type of breaker forms when the ocean bottom has an abrupt slope?

surging

A tsunami may result from:

tectonic activity on the seafloor

Judge the following sentence according to the criteria given below: The same waves break against both headlands and in nearby bays, but their energy is different BECAUSE wave reflection causes the distribution of wave energy to change between them

the assertion is correct, but the reason is incorrect

Judge the following sentence according to the criteria given below: Ocean waves are not considered body waves BECAUSE they transmit energy through the upper part of the ocean near the interface between the atmosphere and the ocean.

the assertion is incorrect but the reason is correct

Judge the following sentence according to the criteria given below: The main cause of rogue waves is theorized to be an extraordinary case of destructive wave interference BECAUSE rogue waves are the suspected cause of many of the approximately 1,000 sinkings that occur each year.

the assertion is incorrect, but the reason is correct

The thickness of sea ice is limited primarily by __________.

the insulating nature of the ice itself

The El Niño Southern Oscillation can best be described as

the relationship between sea surface temperature and changing atmospheric pressure

In a severe warm phase of the El Niño-Southern Oscillation (ENSO), fisheries' productivity on the west coasts of the Americas is dramatically reduced. Which stage of ENSO would come just before the fisheries' collapse?

the thermocline deepens

The Ekman spiral is caused by

the wind and the Coriolis effect.

How are tsunamis generated?

through displacement of the seafloor under water

Equatorial currents are driven by the:

trade winds

Which of the following is true of surface water circulation near Antarctica?

two circumpolar currents dominate it

Surface waters are pushed away from land and replaced by nutrient-rich bottom water through:

upwelling

Diverging surface waters are areas of ________ and ________ productivity.

upwelling; high

The time it takes one full wave to pass a fixed position is called the ________.

wave period

How does wave refraction at headlands affect deposition and erosion

wave refraction at the headland increases erosion

The longer the ________, the faster a deep-water wave travels.

wavelength

The largest wind-generated waves tend to be associated with the:

westerlies

When does a violent storm become a hurricane

when wind speeds exceed 118 kilometers per hour (73 miles per hour)

Surface ocean currents are driven primarily by __________ and modified by __________.

wind; the Coriolis effect and land