Chapter 7 Questions Oceanography Part One 1 How can oceanographers measure surface currents from space Ch 7 Section Surface Current Measurement 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 Ch 7 Section Other Factors Affecting Ocean Surface Circulation 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 Ch 7 Section What Causes Upwelling and Downwelling Convergence of surface currents 4 What causes upwelling Ch 7 Section What Causes Upwelling and Downwelling Agulhas current western Africa 5 What is a western boundary current and how does it form Ch 7 Section Main Components of Ocean Surface Circulation 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 Ch 7 Section Main Components of Ocean Surface Circulation 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 Ch 7 Section Main Components of Ocean Surface Circulation When surface water in a subtropical convergence and the Coriolis effect are balanced 8 What is western intensification Ch 7 Section Main Components of Ocean Surface Circulation 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 Oceanography Questions Part Two 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 Ch 7 Section What Are the Main Surface Circulation Patterns in Each Ocean B The Mid Atlantic Ridge barrier would turn equatorial currents north and northern boundary currents south resulting in two gyres one on each side 2 What is the main cause of surface water sinking to cause the deep thermohaline ocean currents Ch 7 Section Origin of Thermohaline Circulation B 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 Ch 7 Section Sources of Deep Water ABW stays on the bottom and NADW overrides it 4 Which deep waters have been isolated from the surface the longest Ch 7 Section 7 5 Figure 7 27 North Pacific Ocean 5 What is the seasonal pattern of India s monsoon Ch 7 Section Indian ocean Circulation During Winter air over the Asian Mainland rapidly cools creating high atmospheric pressure which causes the wind to blow from southwest Asia off the continent northeast Monsoon During summer the winds reverse 6 What is the Walker Circulation Cell Ch 7 Section Pacific Ocean Circulation Sinking cool air dominates the coastal region of South America On the western boundary it is the opposite Low pressure rising warm air produces cloudy rainy conditions This causes the strong southeast trade winds to blow across the equatorial south Pacific 7 Explain the conditions that cause ENSO warm phase El Ni o Ch 7 Section Pacific Ocean Circulation The high pressure along the coast of south America weakens reducing the difference between the high and low pressure regions of the walker circulation cell 8 Explain the conditions that cause ENSO cool phase La Ni a Ch 7 Section Pacific Ocean Circulation Larger pressure than normal conditions across the Pacific Ocean This larger pressure difference creates stronger walker circulation and stronger trade winds which in turn cause more upwelling a shallower thermocline in the eastern pacific and a and across the equatorial south pacific 9 What is thermohaline circulation Ch 7 Section What Deep Ocean Currents exist Because the density variations that cause deep ocean circulation are caused by differences in temperature and salinity deep ocean circulation is also referred to as Thermohaline circulation 10 Describe the conveyer belt circulation and how it forms Ch 7 Section Worldwide Deep Water Circulation Because the overall circulation pattern resembles a large conveyer belt the model is called conveyer belt circulation Beginning in the north atlantic surface water carries heat to high latitudes via the gulf stream During the cold winter months this heat is transferred to the overlying atmosphere warming northern Europe Chapter 8 Oceanography Questions Part 1 1 What are the primary factors that determine wave height Ch 8 Section Wave Terminology Wind speed length of time wind blows in one direction and fetch If you have two deep water waves with periods of 5 and 10 seconds what can you 2 say about their speeds Ch 8 Section 8 3 Figure 8 8 See figure below The longer period wave will have greater speed Where would it be most likely that you would find internal waves in the ocean 3 Ch 8 Section What Causes Waves At the pycnocline What is the difference between longitudinal waves and transverse waves Ch 8 4 Section How do waves move Longitudinal waves Particles move back and forth in the direction of energy transmission and these waves can transmit matter through solids liquids or gases Transverse waves Particles move back and forth in a direction at right angles to the direction of energy transmission and these waves can transmit energy through solids Describe circular orbital motion Ch 8 Section What characteristics do waves 5 possess Orbital waves Particles move in circular orbits passing through the top half of the orbit in the direction of energy transmission They develop when energy is being transmitted along a density interface between two fluids such as
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