Review for Exam 2

GS 206 REVIEW QUESTIONS Exam 2 Thursday, Nov. 10, 2005 (Covers Chapters 11, 12, 13, 14 in textbook) Distributed Nov. 5, 2005 Ch. 11: THE WORLD OCEAN What are the three major elements dissolved in seawater? Why are the major dissolved elements in river water, Ca and HCO3, present in only minor quantities in seawater? What are the two main kinds of sediment supplied to the deep ocean basins? How important are biogenic contributions and what are they composed? How thick is the upper mixed layer of the oceans? Compare and contrast surface ocean circulation patterns with those of the deeper water masses (i.e. winddriven versus thermohaline circulation). How does the Coriolis force affect the direction of particle motion in the north versus southern hemisphere? Why are polar ocean water masses so important for the circulation of the deep oceans at present? Describe by a sketch the ocean ?conveyor belt? of present circulation- about how long does the entire trip take? What are the changes that happen in rainfall location and coastal upwelling during El Nino events? Photosynthesis and plant life are generally restricted to what water depth limit in the ocean? At what depth, relative to wave length, do waves ?feel bottom? and start to break? What is wave refraction and how does it affect the morphology and sand transport along coastal zones? Describe the tide raising force on the earth- how often do we get high and low tides? What about the role of the sun in causing monthly super high and super low tides? When the last glacial advance was at its maximum, how much lower was global sealevel? Ch. 12: THE COMPOSITION AND STRUCTURE OF THE ATMOSPHERE What are the five variables used to describe the state of the atmosphere at earth?s surface (i.e.weather conditions)? What are the volume proportions of the two most abundant gases in our atmosphere? Explain the greenhouse effect. Why is water vapor (and our weather) restricted to the troposphere? How does temperature vary with altitude in the troposphere? Why is the troposphere height a function of latitude? What is heat capacity and what earth surface substance has the highest heat capacity? Which of the following releases the most heat: freezing water or melting ice; evaporating water or condensing water? Explain how the temperature of air affects the amount of water vapor it can hold at saturation. What is relative humidity? Give examples of three lifting forces that lead to cloud formation and rain. Ch. 13: WINDS, WEATHER, and DESERTS What does the term ?wind chill factor? mean? How do pressure gradients and the coriolis force affect direction and intensity of wind? What are geostrophic winds and why do they blow parallel to pressure isobars? Describe how global atmospheric circulation cells (zones of high and low pressure) would function on a non-rotating earth. Contrast this with atmospheric circulation patterns on our rotating, real earth. What are the three main wind belts in the northern hemisphere and how do they relate to Hadley cells? Where is the jet stream located and how does it relate to the height of the troposphere? How is rainfall distributed in this global circulation model? What is the latitude where the global deserts usually found? Consider two other locations where deserts can form. Why do coastal winds blow onto shore during the day, and offshore in the evening? Do polar marine airmasses carry more water with them than tropical marine air masses? Ch. 14: EARTH?S CHANGING CLIMATE What kinds of evidence have been used to infer that earth?s climate has changed over the last 1000 years? What about the kinds of evidence of change over the last 10?s of thousands of years? What is the duration of the Pleistocene Epoch in years? How many glacial ice sheet advances and retreats occurred over north America during that time? Describe some of the main changes in the earths surface and water budget during glacial periods. Have there been other glacial periods in the geological record of the earth? The Middle Cretaceous Period was very warm and earth was largely ice-free; what mechanism is proposed for this warming? What are the three orbital-astronomical factors that promote changes in the heat budget of the earth? What is the time period of each? Are these factors alone responsible for the onset of glacial events? PAGE PAGE 3