Test #3 Top Ten

TOP TEN THINGS TO STUDY FOR TEST #3

PRINTER FRIENDLY VERSION [pdf]

Test #3 is on Thursday Nov 7, 2013

A Test #3 Study Session
will be held on Wednesday Nov 6th @ 4 - 5 pm in the
Bannister Tree-Ring Building, Room 110

Like Test #1, Test #2 will consist of 10 multiple choice questions. Some questions will be slight variations of the RQ questions, but other questions will be a bit harder than those in the RQ's and they will cover the material in class presentations, in addition to the reading you've been doing for the RQ's.

FOLLOWING ARE THE TOPICS & READINGS COVERED IN TEST #3 (also see the D2L Checklist)

Test #3 will cover Topics #10 through #13.

The readings that accompany these topics are in Chapters 2, (parts of Chapter 3) , Chapter 4, and 15 (pp 295-301) in the SGC-E-text, (with a few additional pages in Dire Predictions listed on the weekly Checklist & Textbook Reading Schedule)

Self Check&/ Readiness Quizzes RQ-5 & RQ-6 will help you to focus on the concepts of these readings that are most important for you to know and understand.

Following are a few more pointers on things to be sure you have read or understood:

The Global Energy Balance -- focus on pp 55 -58 and 129-131 Class Notes (just the top of p 131 -- we didn't cover the rest) and -- especially -- the very important class presentations on Topic #10, Parts I and II.  (Oct 22 & 24 at Class Follow Up)

Chapter 2 in SGC-E-Text on Topic #11 Systems & Feedbacks -- focus on the first part of the chapter and the items emphasized in Self-Test & RQ-5.

Chapter 3 in SGC-E-Text - section on Climate Feedbacks ( pp 53-55)

Chapter 4 in SGC-E-Text goes into a bit more detail than was covered in the presentations on Topic #12 How Climate Works but the items in the Top Ten below will help you focus on the main points. Be sure you understand Figs 4-1, 4-2, 4-3, & have a good grasp of Earth-Sun Relationships and the seasonal climate differences, as in Fig 4-15 and 4-16. Also note that you've seen a version of Fig 4-23 in a previous lectures (tied in with thermodynamics) but here it is again, now being tied into global climate patterns. In addition, the figures discussed in class relating to the Energy Balance ==> the General Circulation of the Atmosphere that are in CLASS NOTES (pp 69-70) for Topic # 12 are very important -- esp. those noted in the "Top 10" items below.

For Ocean Circulation, see the points emphasized in the lectures on Topic #12 especially the figure in the middle of Class Notes p 71 on Poleward heat transport.

In Chapter 15 in SGC focus on the first part that deals with climate changes of the past, pp 295-301.

For Topic #13 Natural Climatic Forcing, review astronomical forcing, solar forcing, and the climatic effect of volcanism as addressed in the Topic #13 classes, the corresponding Class Notes pages, and in Self Test and RQ-6. These 3 topics are also covered in Lesson 2 of the I-1 Climate Science Basics Tutorial.

ASSIGNMENTS:

G-5 Applying the Energy Balance Terms ( p 58 in Class Notes)
I-1 & I-2 Climate Science Basics Tutorials: The Introduction, Lesson 1 & Lesson 2 <== a good Test #3 study aid!

ANIMATIONS: The following animations (which are also linked in your D2L Checklist) may be useful aids for enhancing your understanding of some of the processes you've been learning about

Animations of the Global Energy Balance
              Global Energy Balance
              Shortwave and Longwave Energy Pathways Animation


Animations of Global Energy Balance Map Patterns (these were shown during the Topic #12 lecture)
             Incoming Shortwave Radiation SW
              Outgoing Longwave Radiation LW
              Net Radiation (R net)
             Air Temperature
              See more at:
             http://geography.uoregon.edu/envchange/clim_animations/index.html#Global Energy Balance

Animation showing how a convection cell forms

Formation of Convective Circulation to see how an underlying warm surface can start up a convection cell circulation

Animation of Earth-Sun Relationships that Define the Seasons

              Earth-Sun Relationships

AND NOW THE TOP TEN:

On the TOPIC #10 - THE GLOBAL ENERGY BALANCE:

1. ENERGY BALANCE: Be able to write out and/or recognize the basic Energy Balance Equation (see top of p 55-58 in Class Notes) from memory using the cartoon symbols from class or fill in a missing term or + or - sign if it is blanked out.). Know what each term in the equation means, (e.g., direct SW, diffuse SW, albedo, H, LE G, etc. Understand the overview of The Energy Balance and general "pathways" of SW and LW radiation summarized on p 57 in CLASS NOTES. (Also see the ANIMATION noted above).

Specific Hint #1: Look at the figure on p 55 in CLASS NOTES which shows the amount of energy (in Watts per square meter) involved in each of the different pathways. Note that MORE energy is involved in the pathways of LW related to the Greenhouse Effect (GHE) than just about anywhere else in the Energy Pathways diagram! A huge amount of longwave (LW) energy is transferred back and forth between the Earth's surface and the atmosphere via the GHE. Understand what the difference is between the LEFT side of the equation (the electromagnetic radiation balance part) and the RIGHT side of the equation (the thermal energy balance part, i.e. H, LE, & G). Specific Hint #2:   Do you understand the difference between these two terms??
                                                               vs.

This may help: IR is electromagnetic radiation, it is not heat. Heat can only be sensed after IR is absorbed by the atoms and molecules in a substance which then move faster. H represents the fast-moving atoms and molecules in a substance (like a warm wind, a rising current of hot air in a convection cell, or a warm ocean current like air or water). H can be sensed with a thermometer but IR cannot.

On TOPIC # 11 - SYSTEMS & FEEDBACKS

2. Understand the concept of a SYSTEM, including COUPLINGS, FEEDBACK LOOPS (both positive & negative feedback loops). Know how to recognize whether a coupling diagram is a positive or negative coupling and whether a feedback loop is a positive or negative loop.   Understand that a negative feedback loop is "self regulating" and a positive feedback loop is "self-amplifying."

Specific Hint: Know which type of loop (positive or negative) is associated with a STABLE equilibrium state and which type is associated with an UNSTABLE equilibrium state and know which of these states is of greatest concern with respect to perturbations and forcings leading to global climate change.

Test your understanding:

-- Coupling A-B is negative, Coupling B-C is positive, the complete A-B-C Feedback Loop is positive. Why?
-- The X-Y-Z Feedback Loop is also positive, even though it looks different than the A-B-C Loop. Why?
-- Feedback Loop Q-R is negative and is also the only system diagram shown having a stable equilibrium state. Why?



3. Over and above being able to identify the type of feedback or coupling by its diagram, be able to reason your way through the actual physical processes that are coupled together in the feedback loops shown below (and on pp 27 and 53-54 in SGC) to explain how they work.

Can you do the "Bonus Point" Feedback loop we did in groups on your own?   (see p 65 in Class Notes).

On TOPIC # 12 - HOW CLIMATE WORKS (ATMOSPHERIC & OCEAN CIRCULATION)
HINT: many of the points in items below are succinctly summarized in the CHAPTER SUMMARY on SGC-E-Text (p. 82) and Topic #12 (pp 67-72) in CLASS NOTES.

4. Variations in Energy from the Sun (due to Seasons & the Earth-Sun Relationships) -- Understand what causes the seasons and know what the following terms mean: solstice, equinox, axis tilt (obliquity), aphelion, perihelion (see # 8 below).   Understand how latitudinal differences in solar insolation arise due to Earth-Sun relationships and how the combination of solar intensity (depends on sun angle) and duration (depends on length of day) leads to seasonal and latitudinal differences in how much incoming shortwave solar radiation is received by the Earth (see SGC-E pp 68-70).

5 Atmospheric Circulation - NOTE: This info in Topic #12 will be wrapped up in class on Tuesday Nov 5. Know how and why air circulates (vertically and horizontally). Know key places where subsidence (sinking air) occurs (i.e., the 30º N & S latitude subtropical highs) and why it's linked to the world's largest deserts. Know where air tends to rise (near the equator in what's called the intertropical convergence zone or ITCZ) and why this is linked to the rainy tropics. Know how both these areas are linked to the process called the Hadley circulation (shown along with the ITCZ in Fig. 4-3 in SGC p 61).

Specific Hint: On the small map on p 72 in Class Notes, be able to explain what climates A, B, C & D are like and how they are linked to different parts of the general circulation of the atmosphere.
Specific Hint #2: One of the indicators of a warming world is rising humidity in the atmosphere.(see diagram on p 73 of Class Notes). Can you explain how this indicator is linked to Fig 4-25 in the SGC E-Text (Figure is also shown on p 72 in Class Notes)? See also I-1 Lesson 1 Tutorial Slide 10 on Water Vapor. Can you tie this into the Water Vapor Feedback Loop on p 63 in Class Notes?

6. Global Latitudinal Energy Distribution and Net Radiation --   Understand why more solar energy is received and absorbed by the Earth's surface in the low latitudes (near the equator) and less in the high latitudes (near the poles.) Understand Figure 4-2 in SGC (p 61) and p 69 in CLASS NOTES and be able to link it to the concepts of incoming solar shortwave radiation and outgoing terrestrial longwave radiation and how this leads to energy surpluses and deficits at different latitudes.

Specific Hint: Understand how the figure on the bottom of CLASS NOTES p 70 depicts ways in which energy is transported poleward from surplus to deficit areas of the globe and the role that Hadley Cells, Rossby waves and the transfer of energy from H => LE => H through H₂O phase changes plays in this transport of energy.

7. Ocean Circulation -- Understand how the General Circulation of the Atmosphere (Fig 4-11) drives the circulation of the warm and cool surface ocean currents (p. 71 in CLASS NOTES), especially via the large gyres in the oceans that are steered by winds. Know where the El Niño and La Niña ocean circulations occur and which one tends to be related to warmer temperatures worldwide when it dominates. (covered in the I-2 Lesson 2 Tutorial on Mother Nature' Influence, Slide 16.)

Specific Hint: Understand the relative roles that ocean and atmospheric circulation play in transporting heat poleward in the Northern Hemisphere to balance areas of energy surplus with areas of energy deficit. The question that will be asked will be related to how ocean circulation fits into either the figure on the bottom of p 70 (sensible and latent heat transport) or the figure in the middle of p 71 in CLASS NOTES (poleward transport in the N. Hemisphere).

On TOPIC # 13 - NATURAL CLIMATIC FORCING

8. Astronomical Forcing -- Review the principles that govern the amount of solar energy received by the Earth due to Earth-Sun Orbital Relationships over long periods of geologic time (how much the Earth's axis tilts, how elliptical the shape of the Earth's orbit is, and the variation in the time of year when the Earth is closest to the Sun). NOTE: Astronomical Forcing and the Milankovitch Cycles are covered in the I-2 Tutorial: Lesson 2 "Mother Nature's' Influence" Slides 8-12 <= be sure you study this tutorial!

Specific Hint: Know that at present, the Earth is farthest from the Sun in July (not January) (as in Figure X & Y below -- shown also on p 68 in Class Notes) and what implications this has for the amount of solar insolation received by the Northern Hemisphere during its summer (Jun-Aug) compared to the Southern Hemisphere during its summer (Dec - Feb) . How might the climate of the Northern Hemisphere have been different in the past with the opposite configuration, i.e., when the Earth was farthest from the Sun during the Southern Hemisphere's summer and therefore closest during the Northern Hemisphere's summer (depicted in Figure Z below)?

Figure X Figure Y

Figure Z

NOTE: Items #9 & 10 will be covered in class on Tuesday Nov 5, but they are also in the Lesson 2 Tutorial on Mother Nature's Influence.

9. Solar Variability -- Know that periods of MORE sunspots = GREATER solar brightness and periods of FEWER sunspots = LESS solar brightness. Know where we are on the sunspot "cycle" right now (maximum or minimum). Know why the "Maunder Minimum" period is significant. (answer = dearth of sunspots and a possible factor in the Little Ice Age -- although there were also a lot of volcanic eruptions then). Know also that linking solar variability to temperature trends on Earth has been inconclusive and can't account for all of recent 20th century warming.

Specific Hint: Be able to present a reasoned response to the argument which states that the observed global warming of recent decades (e.g. since the1970s) -- is primarily due to natural solar variability, and is not human-caused. (See Slides 21-26 in the Lesson 2 Tutorial)

10. Volcanism and Climate -- Know how volcanic eruptions can affect climate, understand the process whereby this effect takes place and what the importance of sulfate aerosols is. Know how temperature is affected by an eruption. (See I-2 Tutorial: Lesson 2 "Mother Nature's' Influence" Slides 13-15 and Slide 18)

Specific Hint: Be able to tie all this into the ENERGY BALANCE equation (esp. incoming SW).

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