Chapter 71. How can oceanographers measure surface currents from space?• Ekman transport and current motion cause the water surface to bulge and the departure from normal sea level can be measured by satellite radar2. The Ekman spiral affects the direction of near surface water movement. If you lowered a current measuring device over the side of a ship in the northern hemisphere, what would you observe?• As the instrument descended, the current direction would move progressively to the right of the wind until it was actually going in the opposite direction, and at a greater depth it would have moved to the left3. What causes downwelling?• Convergence of surface currents4. What causes upwelling?• Divergence of surface currents5. What is a western boundary current and how does it form? • When equatorial currents reach the western portion of an ocean basin, they hit land and turn away from the Equator because of the Coriolis effect6. How does an equatorial countercurrent form?• C – water piling up by strong currents in the western margin of an ocean basin creating a downhill gradient for water to come back east7. What is a geostrophic current?• An oceanic flow in which the pressure gradient force is balanced by the Coriolis effect.8. What is western intensification? • is seen as the strong warm water current along the western side of ocean basins (in the US, we think of the Gulf Stream)9. Suppose we could take the Atlantic Ocean north of the equator and divide it into two compartments along a north-south line (for example, if sea level were much lower and the Mid-Atlantic Ridge was emergent along its length). What would happen to the North Atlantic Gyre? • The Mid-Atlantic Ridge barrier would turn equatorial currents north and northern boundary currents south, resulting in two gyres, one on each side10. What is the main cause of surface water sinking to cause the deep, thermohaline ocean currents?• Density increase caused by cold in polar regions; result from sinking of water in polar regions.11. In the Atlantic, North Atlantic Deep Water (NADW) sinks near Greenland and heads south along the ocean bottom. Antarctic Bottom Water (ABW) sinks off Antarctica and moves north along the ocean bottom. What happens when they meet? • ABW stays on the bottom and NADW overrides it.12. Which deep waters have been isolated from the surface the longest?• North Pacific Ocean13. What is the seasonal pattern of India’s monsoon?• NE monsoons occurs in the winter; SE monsoons occur in the summer14. What is the Walker Circulation Cell?• The Walker circulation is the result of a difference in surface pressure and temperature over the western and eastern tropical Pacific Ocean15. Explain the conditions that cause ENSO warm phase (El Niño)? • South-East trade winds weaken and the warm pool on the west pacific spreads east16. Explain the conditions that cause ENSO cool phase (La Niña)?• Stronger trade winds at the equator. Note the cool upwelled water again in the eastern Equatorial region, and the even warmer pool to the west.17. What is thermohaline circulation?• Thermohaline circulation is a very slow and extremely deep movement of water in the oceans around the world. A complete cycle can take thousands of years to complete.• Due to sinking of waters in polar regions.o 3 major types: Antarctic Bottom Water (AABW), North Atlantic Deep Water (NADW), Antarctic Intermediate Water (AAIW)18. Describe the conveyer-belt circulation and how it forms.• Coriolis effect deflects N. Atl. Deep Water to the west and it becomes a Deep Western Boundary Current. This current extends into S. Atlantic, and then into S. Oceans. It then flows into Indian & Pacific Oceans and eventually returns to N. Atlantic as a warm current. This “conveyer belt” flow occasionally shuts down, usually when climate changes. Chapter 81. What are the primary factors that determine wave height?• Wind speed, length of time wind blows in one direction, and fetch2. If you have two deep-water waves with periods of 5 and 10 seconds, what can you say about their speeds? (See figure below) • Wavelength/ period3. Where would it be most likely that you would find internal waves in the ocean? • At in the meeting (between) low-density water and high-density water.• Associated with pycnocline4. What is the difference between longitudinal waves and transverse waves? • In longitudinal waves particles vibrate back and forth…5. Describe circular orbital motion. • Water particles move in circle• Movement up and down and• Back and forth6. How can you calculate wave speed? • Wavelength / period7. What are shallow-water waves?• Waves where the depth is less than 1/20…8. What are transitional waves?• When deep water waves encounter shoaling water less than ½ their wavelength, they become transitional waves.• Characteristic of both deep and shallow water waves.9. Describe how wind-generated waves develop. • Capillary waves gravity waves trochoidal waveforms10. What is constructive interference?• When wave trains having the same wavelength come together in phase11. Why do tsunami waves always behave as shallow water waves?• Because there is no place in the ocean where the depth would be more than 20 times the wavelength of any tsunami.• Their wavelengths are long enough that anywhere in the ocean the water depth is less than L/20.12. What causes tsunamis?• Earthquakes, submarine landslides, large meteor impacts, volcanic eruptions13. Why does wave height increase in shallow water? • As a wave feels the bottom, it slows down, the wave behind closes in and wavelength is decreased, the leftover energy goes towards increasing the wave height.14. What is wave reflection?• Waves and wave energy bounced back from barrier• Reflected wave can interfere with next incoming wave15. What is wave refraction?• As waves approach shore, they bend so wave crests are nearly parallel to shore16. How are standing waves formed?• Two waves with same wavelength moving in opposite directions• Water particles move vertically and horizontally17. How does the tsunami warning system in the Pacific ocean work?• Uses seismic wave recordings to forecast tsunami18. What are the 3 types of breakers and how are they generated?• Spilling breakers – formed by gently sloping sea floor• Plunging breakers – formed by moderately steep floor• Surging breakers – formed by steepest
View Full Document
Unlocking...