Which of the following mechanisms is currently responsible for the generation of new lithospheric material?
a. Upwellings of magma at spreading centers
b. Volcanic activity at convergent plate boundaries
c. Subduction of the continental crust
d. Superplumes of magma from the outer core
Answer: A
Oceanography
- The north-south shifting of the ITCZ and the onset of the monsoons result from seasonal variations caused by the tilt of the Earth's axis.
- The circulation or residence time of most deep water is about 10 to 20years. In contrast, water in the North Atlantic gyre may take only a little more than a year to complete a circuit.
- The slow circulation of water at great depth is driven by density differences rather than by wind energy.
- Which one of the following is a not an eastern boundary current?
- When a cannonball is fired northward from the Equator, it will veer towards the east (clockwise).
- The net motion of water down to about 1 kilometer (1,000meters), after allowance for the summed effects of Ekman spiral, is known as Ekman transport (or Ekman flow).
- Eastern boundary currents are ______.
- It will be exceedingly difficult to limit global warming by decreasing the production of carbon dioxide. We depend on fossil fuel to power the world economy. The world energy demand is projected to increase ________ times between now and 2025, with carbon dioxide emissions _______% higher than today.
- Surface Currents are wind-driven movements of water at or near the ocean's surface. Thermohaline currents are slow, deep, density-driven currents that affect the vast bulk of seawater beneath the pycnocline.
- After an ENSO event, normal circulation sometimes returns with surprising vigor, producing strong currents, powerful upwelling, and chilly, stormy conditions along the South America coast. These contrasting colder than-normal events are given a contrasting name: La Niña.
- Identify the following statement as A.True B.False: life on earth would be safer without the greenhouse effect.
- A single closed-flow circuit of rising warm material and falling cool material is a __________.
- Ocean currents:
- Storms are variations in the earth's normal circulation patterns.
- The lower atmosphere is a nearly homogeneous mixture of gasses, the most plentiful is _________ at 78.1% followed by ___________ at 20.9 %.
- Coriolis deflection of moving air masses is due to which of the following?
- Cold water flows to higher latitudes where heat is transferred to it, then it flows back to low latitudes and releases its heat before the cycle repeats.
- Water of the oceans and water vapor in the atmosphere transfer great quantities of heat from the tropics to the poles. Atmospheric circulation accounts for _____ of the transfer, while ocean circulation accounts for _______.
- We cannot expect science to solve our problems. Most of the decisions and necessary actions fall outside pure science in the areas of values, ethics, morality, and philosophy. The solution to environmental problems, if one exists, lies in ___________________.
- The Hadley-Ferrel-Polar cell model of atmospheric circulation helps describe atmospheric and ocean current convergence and divergence of the northern and southern circulation gyres. Due to the shape of the Earth and the position of the continents on it, the convergence of the subtropical Hadley circulation cells at the ITCZ occurs closest to _____________.
- Due to the combined effect of wind friction, Coriolis Effect, Ekman Transport, land mass, and the pressure gradient, ocean currents tend to __________________.
- Global warming is probably the result of an enhanced greenhouse effect, the trapping of heat by the atmosphere. The greenhouse effect is an unwanted and unnecessary physical effect for life on Earth.
- Who is the first person on record to have sailed solo around the world?
- Western current intensification is not affected by ___________.
- A ____ is huge rotating masses of low-pressure air in which winds converge and ascend. A ________________ is a much smaller funnel of fast-spinning with severe thunderstorms.