Ch. 7 Air-Sea Interaction / AMS OCEAN CURRENTS practice test questions

The tilt of the Earth's axis of rotation with respect to the ecliptic is...

23.5 degrees The tilt of Earth's axis of rotation is 23.5 degrees from the ecliptic.

Globally, air descends (sinks) at

30 degrees latitude. Air is rising at 60 degrees latitude.

In the Northern Hemisphere, the Ekman spiral predicts a net horizontal transport of water through a depth of about 100 m (330 ft) at _____ degrees to the _____ of the surface wind direction.

90.....right

The primary reason that Earth has seasons is because:

Earth's rotational axis is tilted. Because Earth's rotational axis is tilted, it causes the Northern Hemisphere to face more directly into the sun in the summer and away from the sun in the winter (the reverse is true for the Southern Hemisphere).

Which of the following statements is NOT true about the Coriolis effect? In the Northern Hemisphere, moving objects tend to curve to the right of their intended paths; in the Southern Hemisphere, moving objects tend to curve to the left of their intended paths. The Coriolis effect is strongest at the poles and decreases to zero at the Equator. The Coriolis effect tends to increase or decrease the speed of moving objects. The Coriolis effect is caused by Earth's rotation. The Coriolis effect is the result of our perspective on a moving frame of reference (the spinning Earth). All of the above statements are true (none of the above statements are false).

The Coriolis effect tends to increase or decrease the speed of moving objects. This answer is NOT true (the Coriolis effect does not affect the speed of moving objects, only their path); all of the other answers are true.

True or False? Air typically moves from regions of high atmospheric pressure towards regions of low atmospheric pressure.

True Air always moves from high-pressure towards low-pressure regions, producing wind. However, the Coriolis effect can modify the wind's direction, producing cyclonic or anticyclonic flow.

True or False? The surface winds of an anticyclone in the Southern Hemisphere rotate counterclockwise.

True Air flows away from the center of a high pressure cell at the surface and is deflected in the Southern Hemisphere by the Coriolis effect, which makes the air move counterclockwise. Conversely, air in an anticyclone rotates clockwise in the Northern Hemisphere.

True or False? The major wind belts of the world are generated by the lowermost portion of Earth's atmospheric circulation cells.

True Masses of air move across Earth's surface from areas of high pressure to low pressure. Prevailing winds flow in that direction of motion, with some deflection by the Coriolis effect.

True or False? A land breeze flows from land to sea.

True The night air over land cools faster than over the ocean, which creates a high pressure region as the dense air sinks. Since air flows from high-pressure to low pressure, the cool air is forced out to sea, creating a land breeze. See Figure 6.13

In the portion of the North Atlantic under the influence of the circulation of the Icelandic low, Ekman transport causes surface waters to move _____ the center of the cyclone.

away from

Viewed from above in the Northern Hemisphere, ocean currents in subtropical gyres flow in a _____ direction.

clockwise

Where winds generate Ekman transport of surface waters away from the coast, _____ waters circulate up from below (a process called upwelling).

colder, nutrient-rich

The magnitude of the Coriolis effect increases from zero at the _____ to a maximum at the _____.

equator.....poles

Within the pycnocline, sea water density increases with depth because of _____.

falling temperature and/or increasing salinity

Western boundary currents _____.

include the Gulf Stream, are the fastest surface currents in the open ocean, and flow southward in the Southern Hemisphere

In the Northern Hemisphere, warm-core rings form on the _____ side of a western boundary current and rotate

landward.....clockwise

Hurricanes are associated with __________ atmospheric pressure and spin ______________ in the Northern Hemisphere.

low, counterclockwise Hurricanes are associated with low pressure.

Rising warm air is associated with regions of ________ atmospheric pressure caused by thermal ________.

low, expansion

The most abundant gas in the atmosphere is...

nitrogen *carbon dioxide exists in very small amounts.

In the Northern Hemisphere, cold-core rings form on the _____ side of a western boundary current and rotate _____.

ocean.....counterclockwise

The iron hypothesis states that

productivity in the ocean can be stimulated by adding iron. Iron appears to be the nutrient limiting productivity in some tropical waters. The iron hypothesis states that productivity will be stimulated by adding iron to these waters, which will cause increased abundance of photosynthetic algae and, in turn, additional CO2 to be absorbed from the atmosphere.

Based on density, the ocean is divided into three depth zones. The intermediate zone where density increases markedly with depth is known as the_____.

pycnocline

Areas of high atmospheric pressure (at Earth's surface) generally experience what kind of conditions?

sinking air, with dry, clear weather The correct answer is exactly opposite these conditions.

Ultimately, wind-driven ocean currents are maintained by _____ energy.

solar

In the Northern Hemisphere, the Coriolis effect causes a southward flowing ocean current to shift toward the _____.

southwest

Upwelling _____ biological productivity in the sun-lit surface waters of the coastal zone and along the equator.

spurs

Ninety percent of people that are killed by hurricanes are killed by

storm surge.

Legend holds that the "horse latitudes" derived their name from sailors who, in desperation, abandoned horses overboard because the sailors were

stuck at the boundary between the trades and the westerlies. The horse latitudes are centered on latitudes 30 degrees north and south.

A water mass is a large, homogeneous volume of ocean water having a characteristic range of _____.

temperature & salinity

"Midnight Sun" is a phenomenon observed in Northern Hemisphere polar regions only when the Sun is directly above

the Tropic of Cancer. The Sun never gets directly overhead at the North Pole.

A moving object traveling northward in the Northern Hemisphere is deflected toward...

the east Based on the Coriolis effect, a moving object in the Northern Hemisphere curves to the right, or toward the east.

At the time of the vernal equinox, the Sun is directly overhead at

the equator. The sun is directly above the equator during both the vernal and autumnal equinox.

The Ekman spiral is caused by _____.

the frictional coupling of successive layers of water and the Coriolis effect

In regions of the ocean basin under the influence of the circulation of a subtropical anticyclone (high), Ekman transport causes surface waters to move _____ the center of the anticyclone.

toward

Winds blowing from the north along the west coast of North America induce coastal _____.

upwelling

Thermohaline circulation is driven primarily by slight differences in water density caused by variations in _____.

water temperature and salinity

Overall, the gas that contributes the greatest amount of greenhouse warming is

water vapor. * Carbon dioxide is less important than water vapor in contributing to global warming.

Trade winds of the Northern and Southern Hemispheres drive equatorial currents and sun-warmed surface waters toward the _____.

west

In both hemispheres, the ocean-surface slope is steeper on the _____ sides of subtropical gyres

western

Sea ice forms by seawater freezing; icebergs form...

when glacial ice on land falls off into the ocean. Icebergs form when glacial ice on land calves off into the ocean.