Test 2 study guide 80 of questions on test Chapter 7 part 1 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 actually was going in the opposite direction and at greater depth it would move to the left 3 What causes downwelling Convergence of surface currents 4 What causes upwelling Agulhas current western Africa 5 What is a western boundary current and how does it form When equatorial currents reach the western portion of an ocean basin they must turn because they cannot cross land The coriolis effect deflects these currents away from the equator as western boundary currents They travel along the western boundary of their respective ocean basins 6 How does an equatorial countercurrent form Water is piled up by strong currents in the western margin of an ocean creating a downhill gradient for water to come back east 7 What is a geostrophic current When surface water in a subtropical convergence and the Coriolis effect are balanced 8 What is western intensification When the western part of the hill formed within a rotating gyre is closer to the western boundary than the center of the gyre As a result the western boundary currents of the subtropical gyre are faster narrower and deeper than their eastern boundary current counterparts Chapter 7 part 2 1 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 geysers one on each side 2 What is the main cause of surface water sinking to cause the deep thermohaline ocean currents Density increase caused by cold in polar regions 3 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 NADW stays on the bottom and ABW overrides it 4 Which deep waters have been isolated from the surface the longest North Pacific Ocean 5 What is the seasonal pattern of India s monsoon During winter southwest Asia off the continent and out over the ocean During summer winds reverse 6 What is the Walker Circulation Cell High pressure and sinking air in south America low pressure in other side of pacific The pressure difference causes the strong southeast trade winds to blow across South Pacific Atmospheric circulation cell is named walker circ cell 7 Explain the conditions that cause ENSO warm phase El Ni o Low pressure low southeast tradewinds 8 Explain the conditions that cause ENSO cool phase La Ni a Large pressure difference strong trade winds 9 What is thermohaline circulation Surface water sinking because of density increase caused by cold in polar regions 10 Describe the conveyer belt circulation and how it forms Thermohaline circulation surface currents Heat transfers cooling increases density Chapter 8 part 1 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 the longer period wave will have greater speed 3 Where would it be most likely that you would find internal waves in the ocean At the pycnocline 4 What is the difference between longitudinal waves and transverse waves In longitudinal waves the particles that vibrate push and pull in the same direction that the energy is traveling In transverse waves energy travels at right angles to the direction of the vibrating particles 5 Describe circular orbital motion As the wave travels the water passes the energy along by moving in a circle 6 How can you calculate wave speed The distance traveled by the travel time Wavelength L Period T 7 What are shallow water waves Waves in which depth is less than 1 20 of the wavelength L 20 8 What are transitional waves Waves that have some characteristics of both shallow water and deep water waves 9 Describe how wind generated waves develop They originate in a windy region of the ocean and move across great expanses of open water without subsequent aid of wind and terminate when they break and release their energy 10 What is constructive interference Occurs when waves of the same wavelength come together in phase crest to crest and trough to trough producing waves of greater height Chapter 8 part 2 1 Why do tsunami waves always behave as shallow water waves Their wavelengths are long enough that anywhere in the ocean the water depth is less than L 20 2 What causes tsunamis Fault movement the underwater fault movement displaces Earth s crust generates earthquakes and if it ruptures the sea floor produces a sudden change in water level at the ocean surface 3 Why does wave height increase in shallow water Wave orbital motion is constricted by the sea bottom 4 What is wave reflection A vertical barrier such as a seawall or a rock ledge can reflect waves back into the ocean with little loss of energy 5 What is wave refraction The process by which the part of a wave in shallow water is slowed down causing the wave to bend and align itself nearly parallel to the shore 6 How are standing waves formed They are produced when waves are reflected at right angles to a barrier sum of two waves with the same wavelength moving in opposite directions resulting in no net movement 7 How does the tsunami warning system in the Pacific ocean work It coordinates info from 25 pacific rim countries and is headquartered in Ewa Beach Hawaii It uses seismic waves to forecast destructive tsunami DART 8 What are the 3 types of breakers and how are they generated Spilling breaker turbulent mass of air and water that runs down the front slope of the wave as it breaks result from a gently sloped ocean bottom which gradually extracts energy from the wave over an extended distance and produces
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