General Oceanography Geology 105 Expedition #19 The Ocean and Climate

Transcription

1 General Oceanography Geology 105 Expedition #19 The Ocean and Climate Name Not attempting to answer questions on expeditions will result in point deductions on course workbook (two or more blank answers will result in a deduction of 2-4 points; a 5 point deduction will be assessed if more than five answers are left blank). Objective: Establish the link between ocean circulation and climate First we will examine the boundary currents, both the western and eastern, since examples of each impacts the climate of the United States, as well as many other nations in the world. Second we will look at coastal upwelling along central and northern California, which has a powerful effect on the climate in the bay area and operates on seasonal time-scale. And third, we will look at the global conveyor belt, a combination of deep (thermohaline) circulation and surface, wind-driven circulation that transports heat through the oceans causing major climatic effects on a time-scale of decades, centuries and millennia. 1. Introduction - Ocean and Climate Why is the ocean used to forecast the long-range weather? How might global warming affect the ocean and climate? General Oceanography, GEOL 105, Summer 2012 Session II Page 205 of

2 2. The California Current - And It's Not Some Trendy Bistro! --Jim Bettinger Draw an arrow on the map below showing the flow direction of the California current What effect does this current have on climate along northern and central California? 3. Current Marine Conditions - let's examine the today's conditions at several buoys (floats) with instruments - Complete by the table below - Note that station is in the open ocean whereas the other stations are closer to the coast. If station is not yet operational, then go into sea temperature listed below Climatic summary table line and determine the average sea temperature for this month from the graph (midpoint on red line). Do the same thing for air temperature, and put these under in the table below. Real-Time Observation ) Latitude 2) Longitude 3) Location Description 4) Air temperature 5) Water temperature General Oceanography, GEOL 105, Summer 2012 Session II Page 206 of

3 On the map above, draw a pattern of your choice in the regions of the coldest surface water 4. Acquiring Data on the Wind By means of arrows, show the prevailing wind direction off California during the spring and summer General Oceanography, GEOL 105, Summer 2012 Session II Page 207 of

4 5. Making a Model Let s examine the wind and surface water flow in the coastal ocean Make two diagrams (depth view and top view) showing the direction of water motion in the Ekman layer below the wind. 6. Why is the water at the coast so cold along California? We now have the two pieces of puzzle..think eastern boundary currents first and then cold, rising water Give two reasons for the cold sea surface temperature off central and northern California a. b. Put arrows on the drawing below to show the combination of the south-flowing California current and coastal upwelling, in addition to the prevailing wind direction along the California coast in the spring and summer North Ocean Coast Land General Oceanography, GEOL 105, Summer 2012 Session II Page 208 of

5 7. Other Aspects of Upwelling How do the ocean conditions set up by the eastern boundary currents encourage upwelling? What other regions of the ocean exhibit upwelling? 8. Monterey Bay National Marine Sanctuary Let s move to the south into the neighboring Monterey Bay National Marine Sanctuary. How does upwelling set the framework for the marine ecosystem along California? 9. Upwelling and Regional Climate How does upwelling influence the climate along the coastline of northern and central California, especially during the spring and summer months? General Oceanography, GEOL 105, Summer 2012 Session II Page 209 of

6 10. Combining Surface Circulation with Deep Circulation - the Global Conveyor Belt What is the driving force behind circulation of the deep waters? What is one technique use to track the deep currents? 11. Influence of the Conveyor Belt How does the deep circulation influence life on our planet? 12. Tracking Deep Ocean Current Let s Deploy Argo Floats Describe three ways that you will use to track the flow of deep water (thermohaline) circulation a. b, c. 13. Let s Ride the Global Conveyor Belt Using the methods described on the previous problem, let s track the deep water movement. What property is being used as a tracer in this example? General Oceanography, GEOL 105, Summer 2012 Session II Page 210 of

7 Use your research during the rest of the expedition to draw the global ocean conveyor on the map below with different colored pencils; use orange or red arrows for the direction of the warm surface currents (orange or red) and blue or purple arrows for the cold, salty deep currents Global Map General Oceanography, GEOL 105, Summer 2012 Session II Page 211 of

8 Why does the ocean have a high salinity in the North Atlantic? Draw on the global map, the flow of the Gulf Stream into the north Atlantic and into the Norwegian-Greenland Sea and also the flow of high salinity water out of the Mediterranean Sea. 14. Mischief in the Norwegian-Greenland Sea How might the sinking of North Atlantic Deep Water (NADW) in the Norwegian- Greenland Sea influence the global climate? Make a diagram of the flow of "warm, salty" water into the North Atlantic and the sinking of cold, salty, oxygen-rich water in the Norwegian-Greenland Sea 0 meters Equator Sea Surface Greenland Seafloor Water Depth 4000 meters Seafloor General Oceanography, GEOL 105, Summer 2012 Session II Page 212 of

9 If the ice mass in Greenland continues to melt (see audio clip), how might this influence the salinity of the ocean water in the Norwegian-Greenland Sea, and how might this influence the ability of surface water to sink, and thereby the global conveyor belt? 15. Into the South Atlantic - remember to show the flow of water into the south Atlantic on the global map from both the north and south Use the diagram below to show how oxygen-rich deep water is provided to the south Atlantic? Label the NADW and AABW water masses. 0 meters Antarctica Sea Surface Equator Greenland Water Depth 4000 meters Seafloor Surface Latitude 16. Into the Indian Ocean - remember to show the flow of deep water into the Indian Ocean on the global map What happens to the deep water flow of the conveyor belt in the Indian Ocean? General Oceanography, GEOL 105, Summer 2012 Session II Page 213 of

10 17. Into the South Pacific - remember to continue your diagram on the global map Describe what happens to the flow of the conveyor belt in the Pacific Ocean. 18. Into the North Pacific - remember to continue your diagram on the global map Where does the global conveyor belt go after mixing with intermediate and shallow water in the north Pacific? 19. Through the Philippines and Indonesia and into the Indian Ocean - continue on your global page (I studied this portion of the conveyor as a portion of my doctoral work) 20. Across the Indian Ocean - continue your global map How do surface currents (see your surface circulation map in the previous expedition) assist in the westward flow of the conveyor belt in the Indian Ocean? General Oceanography, GEOL 105, Summer 2012 Session II Page 214 of

11 21. Back into the Atlantic Ocean - continue your global map How does the water of the conveyor belt make its way back into the north Atlantic Ocean? 22. As we gain more knowledge, simple models often become more complex. Explain how recent work is leading to a modification of ideas on the southward flow of deep water in the north Atlantic. 23. Ignoring the Science and Misinterpreting Scientific Results Explain how recent work has been misinterpreted for political means, rather than science. 24. Let s Join Dr. Ruth Curry in a Simple Experiment on Climate Change and the Ocean What does this experiment say about the role of sea ice and the ocean in climate change? General Oceanography, GEOL 105, Summer 2012 Session II Page 215 of

12 1 minute essay - Summarize what you learned in this expedition - Avoid the "I learned a lot about" syndrome - show some insight I am here to help you learn the material. Remember that answer keys are not provided after exam #1, please do a selfassessment of your learning in this expedition and post any questions that you may have in the "Exped 19 Ocean & Climate - Any Questions" in the Desire2Learn Discussion area. In order to receive credit for completing this expedition, Go to Desire2Learn and send Bye Don End Expedition 19 in Subject Line. Include "Bye Don" in body of , Include Completion Word (see last page of expedition) and write your name in body of message General Oceanography, GEOL 105, Summer 2012 Session II Page 216 of