Unit 5: Balancing the Radiation Budget: A Jigsaw Exploration of the Global Climate System (Part 2)

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Map illustrating global impacts attributed to climate change from the Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report.

Provenance: Figure SPM.2 (p. 7) from IPCC, 2014: Summary for policymakers. In: Climate Change 2014: Impacts, Adaptation, and Vulnerability. Part A: Global and Sectoral Aspects. Contribution of Working Group II to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Field, C.B., V.R. Barros, D.J. Dokken, K.J. Mach, M.D. Mastrandrea, T.E. Bilir, M. Chatterjee, K.L. Ebi, Y.O. Estrada, R.C. Genova, B. Girma, E.S. Kissel, A.N. Levy, S. MacCracken,P.R. Mastrandrea, and L.L. White (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, pp. 1-32.
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Learning Goals

By the end of the unit, students will be able to:

1. Estimate relative balance (balance, excess, deficit) from graphs of the major components of Earth's radiation budget.
2. Create concept sketches to effectively communicate spatial variation in earth's radiation balance and hypothesized physical causes.
3. Explain how atmospheric circulation acts to balance the radiation budget.
4. Generate hypotheses for the patterns of the global impacts of climate change using their understanding of the global climate system.

Unit 5 is a continuation of the map-based jigsaw (see this Jigsaw module for more information on jigsaws) begun in Unit 4. This activity builds on fundamental concepts introduced in Units 1-3 of the module. The jigsaw could be used as a stand-alone activity as long as students are familiar with concepts of electromagnetic and blackbody radiation.

The activity is designed to be divided between two 50-minute classes, but could be combined in a single extended lab period (~2 hours or more). For instructors teaching the entire module in a 75-minute class format the activity can be split after students complete their synthesis group concept sketches. Synthesis group work would immediately follow specialty group work in unit 4 (the balance question can be used as a transition) and the whole class discussions would be completed in the net class period immediately before starting Unit 6.

This activity can be completed by classes of 6 or more students. For larger classes there may be multiple groups interpreting the same geographic region. Instructors of large classes can ask each of these groups to comment on specific regions of radiation excess/deficit and their causes in order to include all groups in the summary discussion.

Introduction

In this activity, students analyze data from the NASA Earth Radiation Budget Experiment (ERBE). These data are presented in a series of maps:

• NASA ERBE January clear sky maps (Acrobat (PDF) 1.4MB Nov1 16)

A student handout helps guide the students through the activity:

• Student Handout Radiation Balance Jigsaw Synthesis (Microsoft Word 46kB Aug31 16) (also available as a PDF (Acrobat (PDF) 97kB Aug31 16)).

In Unit 5, students regroup into synthesis groups where they explain to the group their specialty map and the underlying physical properties it reflects. They then work together to create concept sketches that integrate a longitudinal graph and map to illustrate the spatial variations in the global radiation balance and their underlying causes.

• Synthesis Sketch Sheet (Microsoft Word 23kB Nov18 16), also available as a PDF (Acrobat (PDF) 762kB Nov18 16)

The associated Unit 5 Presentation Slides (PowerPoint 2007 (.pptx) 26.5MB Nov18 16) can be used to introduce the activity, guide the students through each task, and lead students in a final in-class discussion. Specific slides for each of these tasks are listed in the detailed description below.

In class you will need

• Chalkboard or whiteboard for final discussion
• Copies of Student Handout Radiation Balance Jigsaw Synthesis (Microsoft Word 46kB Aug31 16), also available as a PDF (Acrobat (PDF) 97kB Aug31 16), and Synthesis Sketch Sheet (Microsoft Word 23kB Nov18 16), also available as a PDF (Acrobat (PDF) 762kB Nov18 16) for each student (note that the synthesis sketch sheet contains 4 pages, one for each of the suggested longitudinal lines).
• Copies of NASA ERBE January clear sky maps (Acrobat (PDF) 1.4MB Nov1 16) for each synthesis group. Ideally, maps should be printed at 11"x17" size on high-quality paper so that students can clearly see the data and infer patterns.
• Unit 5 Presentation Slides (PowerPoint 2007 (.pptx) 26.5MB Nov18 16) to introduce, guide, and synthesize the activity.

Prior to class

Students who missed part 1 of the activity should complete the work on their own, if possible.

Lay out a set of the three ERBE maps for each synthesis group before class. As students enter the classroom you can remind them of their assignments and have them sit at the appropriate location. For larger classes you will probably want to have some help with this! You may need to combine some groups if students are absent.

Part 1: Radiation Balance (35 minutes total)

5 minutes: Review of activity, introduce learning objectives for the day and discuss the definition of and equation for the radiation balance. Unit 5 Presentation Slides (PowerPoint 2007 (.pptx) 26.5MB Nov18 16) slides 1-6.

10 minutes: Students briefly present their specialty group map and concept sketch to the other members of their specialty group. Students proceed to plot profiles of the three radiation components along their assigned longitude line (task 1 of the Student Handout Radiation Balance Jigsaw Synthesis (Microsoft Word 46kB Aug31 16), also available as a PDF (Acrobat (PDF) 97kB Aug31 16)) on the graph provided at the top of Synthesis Sketch Sheet (Microsoft Word 23kB Nov18 16), also available as a PDF (Acrobat (PDF) 762kB Nov18 16). Students are then asked to consider how they might determine the radiation balance from this graph. Unit 5 Presentation Slides (PowerPoint 2007 (.pptx) 26.5MB Nov18 16) slide 7 provides a prompt for this part of the activity. Slides 8-10 are provided to foster a whole-class discussion of how we can estimate deficit-balance-excess from a graph, using U.S. trade as an example.

10 minutes: Complete graph and map concept sketches. Students determine the radiation balance along their assigned longitude line using the graph they created in task 3 (task 2 of the Student Handout Radiation Balance Jigsaw Introduction and Specialty Group (Microsoft Word 49kB Nov18 16), also available as a PDF (Acrobat (PDF) 99kB Nov18 16)). Students then create a map-based sketch of the radiation balance using the strip map on the bottom of Synthesis Sketch Sheet (Microsoft Word 23kB Nov18 16), also available as a PDF (Acrobat (PDF) 762kB Nov18 16). They should annotate the graph and map to illustrate regions of radiation excess and deficit as well as their interpretations of the physical causes for the patterns they observe. Unit 5 Presentation Slides (PowerPoint 2007 (.pptx) 26.5MB Nov18 16) slide 11 provides a prompt for this part of the activity.

10 minutes: Summary discussion. The instructor will guide a whole-class discussion of Earth's radiation balance calling on student specialty groups to illustrate the various points. Unit 5 Presentation Slides (PowerPoint 2007 (.pptx) 26.5MB Nov18 16) slides 12-19 present the data (even numbered slides) and the energy balance (odd numbered slides) for a suite of longitudinal slices.

Potential questions for discussion include:

• Where on Earth is there an excess of radiation (+ balance) in January?
• Where on Earth is there a deficit of radiation (- balance) in January?
• What is the primary driver of this imbalance?
• What secondary patterns do you observe?
• What are the underlying causes of these secondary differences?
• How do Northern and Southern hemispheres differ?

Part 2: Balancing the Global Radiation Budget (15 minutes total)

15 minutes: A guided lecture and discussion of the role that atmospheric circulation plays in balancing the radiation budget, its effect on global precipitation patterns, and the impacts of a changing climate. This discussion is facilitated with slides 20-30 in Unit 5 Presentation Slides (PowerPoint 2007 (.pptx) 26.5MB Nov18 16). Three images are used as focal points for think-pair-share reflections, with guidance in the Notes section of the PowerPoint:

• How does atmospheric circulation balance the global radiation budget? (slide 26)
• How does global atmospheric circulation affect patterns of precipitation? (slide 28)
• How might a warming climate change circulation patterns and impact other Earth systems? (slide 30)

Slides 20-21 are provide an introduction to the discussion. Slides 22-23 review key concepts. Slides 24-25 introduce the data presented in slides 26 and 28. Slides 27 and 29 provide additional relevant background that may be helpful when discussing slides 26 and 28, respectively.

Note that this discussion can be replaced by the optional atmospheric circulation jigsaw for instructors who wish to dedicate more time (~100 minutes) to investigating atmospheric circulation patterns and their role in balancing the global radiation budget.

Optional/Take-home

Question E2 from the Optional questions Units 4 and 5 (Microsoft Word 35kB Nov18 16) (also available as a PDF (Acrobat (PDF) 55kB Nov18 16)) asks students to reflect on cloud effects and can be completed now if time permits or later as a homework assignment. The following point could be added to the discussion above if the students have completed these questions. Students will need access to the ERBE maps with clouds (Acrobat (PDF) 2.1MB Sep21 16) in digital or printed form to complete this portion of the activity. Unit 5 Presentation Slides (PowerPoint 2007 (.pptx) 26.5MB Nov18 16) slide 31.

• What effects do clouds have on the radiation balance?

Unit 5 is the second half of the full jigsaw activity, split so that the activity can be completed in two 50-minute classes (see Unit 4 description for more details).

Synthesis group (longitude/hemisphere) assignments must be made prior to the start of Unit 5. Synthesis group seating should be clearly marked so that groups sit together when entering the classroom.

The unit slide set is set up to help guide the opening discussion, activity, and transition discussion. The relevant slide numbers for each portion of the unit are noted in the appropriate piece of the Description and Teaching Materials above. Notes associated with each slide also provide points for discussion.

By roaming the room while student groups are working, instructors can monitor progress, answer questions, and clear up any student misconceptions.

The discussion of determining balance from a graph using the trade balance could be moved to immediately follow the discussion of the radiation balance if the instructor wishes.

Units 4 and 5 can be readily combined into one longer period (100+ minutes). The balance question can still be used as a transition before a short break and time for students to regroup into their geographic synthesis groups. You may want to provide each specialty group with one map per group member so that they can take them to their specialty group, saving you the need to re-shuffle the maps for the second part of the activity.

Note that the final discussion in Unit 5 can be replaced by the optional atmospheric circulation jigsaw for instructors who wish to dedicate more time (~100 minutes) to investigating atmospheric circulation patterns and their role in balancing the global radiation budget.

Learning outcomes for unit 5:

1. Estimate relative balance (balance, excess, deficit) from graphs of the major components of Earth's radiation budget.

• Assessed by synthesis graph-based concept sketch

2. Create concept sketches to effectively communicate spatial variation in earth's radiation balance and hypothesized physical causes.

• Assessed by synthesis map-based concept sketch

3. Explain how atmospheric circulation acts to balance the radiation budget.

• Assessed by think-pair-share activity

4. Generate hypotheses for the patterns of the global impacts of climate change using their understanding of the global climate system.

• Assessed by think-pair-share activity

Although students work in groups they are expected to complete their own graph and map-based concept sketches. Rubrics are provided for each of these components in the Student Handout Radiation Balance Jigsaw Synthesis (Microsoft Word 46kB Aug31 16), also available as a PDF (Acrobat (PDF) 97kB Aug31 16). Answers and rubric for the additional question are provided in

Optional questions answers and rubric -- private instructor-only file

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PDF -- private instructor-only file

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Exam questions tied to the unit's learning goals can be found here:

Radiation balance exam questions -- private instructor-only file

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PDF -- private instructor-only file

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Instructors may use the Concept Sketch Pre and Post Survey (Word) (Microsoft Word 2007 (.docx) 23kB Nov18 16), also available as a PDF (Acrobat (PDF) 42kB Nov18 16) in class or as a take-home assessment tool.

• Details on the ERBE mission can be found at http://science.nasa.gov/missions/erbs/ and http://science.larc.nasa.gov/erbe/
• ERBE data downloaded from http://iridl.ldeo.columbia.edu/SOURCES/.NASA/.ERBE/
• This activity was initially inspired by Dale Sawyer's Discovering Plate boundaries plate tectonic jigsaw http://plateboundary.rice.edu. A similar activity was developed independently by Christa Farmer http://serc.carleton.edu/NAGTWorkshops/hurricanes/activities/28219.html. We acknowledge inspiration from both of these sources while preparing materials for this unit.