Chapter 7 1 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 radar 2 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 left 3 What causes downwelling Convergence of surface currents 4 What causes upwelling Divergence of surface currents 5 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 effect 6 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 east 7 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 side 10 What is the main cause of surface water sinking to cause the deep thermohaline ocean Density increase caused by cold in polar regions result from sinking of water in currents 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 Ocean 13 What is the seasonal pattern of India s monsoon NE monsoons occurs in the winter SE monsoons occur in the summer 14 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 Ocean 15 Explain the conditions that cause ENSO warm phase El Ni o South East trade winds weaken and the warm pool on the west pacific spreads east 16 Explain the conditions that cause ENSO cool phase La Ni a 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 8 1 What are the primary factors that determine wave height Wind speed length of time wind blows in one direction and fetch 2 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 period 3 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 pycnocline 4 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 forth 6 How can you calculate wave speed Wavelength period 7 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 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 waveforms 10 What is constructive interference When wave trains having the same wavelength come together in phase 11 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 eruptions 13 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 wave 15 What is wave refraction As waves approach shore they bend so wave crests are nearly parallel to shore 16 How are standing waves formed Two waves with same wavelength moving in opposite directions Water particles move vertically and horizontally 17 How does the tsunami warning system in the Pacific ocean work Uses seismic wave recordings to forecast tsunami 18 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 sea floor Chapter 9 1 Differentiate between apogee and perigee and discuss the effect on tidal height when perigee coincides with spring tide Apogee is the farthest point from the Earth to the moon perigee is the closest point from the Earth to the moon Higher tides or greater variation in the high and low tide occur
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