Unit 4: Balancing the Radiation Budget: A Jigsaw Exploration of the Global Climate System (Part 1)

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Artst's rendition of NASA’s Earth Radiation Budget Satellite (ERBS) investigating how energy from the Sun is absorbed and re-radiated by the Earth.

Provenance: NASA Earth Observing System, Freely available for re-publication or re-use, https://eospso.nasa.gov/sites/default/files/sat/ERBSat.jpg
Reuse: This item is in the public domain and maybe reused freely without restriction.

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

1. Explain the physical causes for spatial variation of each of the major components of Earth's radiation balance.
2. Interpret maps of radiation data to identify patterns and hypothesize their physical causes.
3. Create concept sketches to effectively communicate observations and interpretations.

Units 4 and 5 introduce students to spatial variability in the global radiation balance while building on fundamental concepts introduced in Units 1-3. These two units could be used as a stand-alone activity as long as students are familiar with concepts of electromagnetic and blackbody radiation.

The core of this activity is a map-based jigsaw (see this Jigsaw module for more information on jigsaws). 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 the initial map interpretation so that the introduction (part 1) occurs at the end of Unit 3 and specialty group mapping (part 2) is completed prior to beginning Unit 5.

This activity can be completed by classes of 6 students or more. For larger classes, there will be multiple specialty groups interpreting the same data maps.

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 Introduction and Specialty Group (Microsoft Word 49kB Nov18 16); also available as a PDF (Acrobat (PDF) 99kB Nov18 16).

In Unit 4, students work in small specialty groups to interpret map(s) from one of the wavelength bands measured by the ERBE. Students are asked to interpret the data in the context of the material they have learned in the first half of the module (Units 1-3). They are asked to create a concept sketch in map form using the Student Basemap (Microsoft Word 2007 (.docx) 1.1MB Nov18 16) (also available as a PDF (Acrobat (PDF) 1.1MB Nov18 16)). They will use these maps at the beginning of Unit 5 to explain their specialty map and the underlying physical properties it reflects to a new group of their peers.

The associated Unit 4 Presentation Slides (PowerPoint 2007 (.pptx) 6.3MB Nov18 16) can be used to introduce the activity, guide the students through each task, and as an outline for 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 Introduction and Specialty Group (Microsoft Word 49kB Nov18 16) (also available as a PDF (Acrobat (PDF) 99kB Nov18 16)) and Student Basemap (Microsoft Word 2007 (.docx) 1.1MB Nov18 16) (also available as a PDF (Acrobat (PDF) 1.1MB Nov18 16)).
• 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 4 Presentation Slides (PowerPoint 2007 (.pptx) 6.3MB Nov18 16) to introduce, guide, and synthesize the activity.
• Optional: copies of Synthesis Sketch Sheet (Microsoft Word 23kB Nov18 16) (also available as a PDF (Acrobat (PDF) 762kB Nov18 16)) for plotting profiles of specialty group data in order to expedite synthesis group work on day 2, if time permits.

Prior to class

Each student should be assigned to a specialty (short wave in, short wave out, long wave out) and synthesis group (by longitude and hemisphere) prior to class. Perhaps the easiest way to do this is by printing slips of paper with the assignments to handout as student enter the classroom (this Example table for assigning student groups (Excel 2007 (.xlsx) 36kB Nov18 16) presents an example for a class of 18).

Specialty groups of 2-4 students are optimal so that all group members can see the map and be involved in the discussion. For larger classes, create multiple groups of each specialty. Divide the students as equally as possible between the specialties. Synthesis groups should ideally consist of three members, one from each specialty, assigned to a specific longitude and hemisphere. If your class numbers do not permit this, you will have to make some groups with duplicate specialists. Try to spread groups geographically to explore hemispheric as well as land/sea differences (some good possibilities include 150W, 60W, 120E). You may need to do a little shuffling of assignments before you start if some students are absent.

Lay out maps with group names before class. As students enter the classroom, you can hand them their assignment and have them sit at the appropriate location. For larger classes, you will probably want to have some help with this!

Part 1: Introduction and initial exploration of the maps (25 min)

10 minutes: Introduce activity and learning objectives using slides 1-7 of the Unit 4 Presentation Slides (PowerPoint 2007 (.pptx) 6.3MB Nov18 16). Use the map of global impacts of climate change (slide 3) to foster a discussion of why spatial variation in climate matters and of how we communicate with maps. Slides 4-5 provide a chance to practice identifying spatial patterns, generate hypotheses based on these patterns, and create a map to communicate patterns and interpretations. Slides 6-7 introduce the Earth's Radiation Budget Experiment within the context of the module.

15 minutes: Students meet with their specialty groups and answer guiding questions (task 1 on page 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)). Unit 4 Presentation Slides (PowerPoint 2007 (.pptx) 6.3MB Nov18 16) slide 8 provides a prompt. The questions on the handout are primarily designed to help students to identify patterns and consider their causes. The instructor (and TAs for larger classes) should walk the room at this time to check on group progress, answer questions, and encourage students look closely and think deeply about their data. End with a 5-minute class discussion of the data sets and physical processes, using Unit 4 Presentation Slides (PowerPoint 2007 (.pptx) 6.3MB Nov18 16) slides 9-11.

Part 2: Construction of concept sketches (25 minutes total)

20 minutes: Students continue to work in their groups creating map-based concept sketches on the Student Basemap (Microsoft Word 2007 (.docx) 1.1MB Nov18 16), also available as a PDF (Acrobat (PDF) 1.1MB Nov18 16) that clearly illustrate the major patterns they see in their data and the underlying process(es) that are most likely responsible for generating these patterns (task 2 on page 3 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)). Unit 4 Presentation Slides (PowerPoint 2007 (.pptx) 6.3MB Nov18 16) slide 12 provides a prompt. By the end of this time all groups should be prepared to hand in their concept sketch and to discuss the data with their classmates in synthesis groups (Unit 5). The instructor (and TAs for larger classes) should walk the room at this time to check on group progress, answer questions, and encourage students to create maps that clearly communicate their observations and interpretations.

If time permits, you may want to have students plot a profile of their specialty group data for the longitude line that they have been assigned for Unit 5 (synthesis group). Plotting the data on day 1 will help to expedite day 2 and leave more time for discussion at the end of the activity. Students will need a copy of the appropriate page from Synthesis Sketch Sheet (Microsoft Word 23kB Nov18 16), also available as a PDF (Acrobat (PDF) 762kB Nov18 16). Unit 4 Presentation Slides (PowerPoint 2007 (.pptx) 6.3MB Nov18 16) slide 13 is provided as a prompt.

5 minutes: Introduce the question of radiation balance to be discussed at the beginning of Unit 5. Unit 4 Presentation Slides (PowerPoint 2007 (.pptx) 6.3MB Nov18 16) slide 14.

Optional/Take-home

Question E1 from 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 seasonal effects and can be completed in class, if time permits, or as a possible homework assignment. The following point could be added to the discussion above if the students have completed these questions. Unit 4 Presentation Slides (PowerPoint 2007 (.pptx) 6.3MB Nov18 16) slide 15.

• How would your radiation component vary over the course of a year?

The full jigsaw activity is split between Units 4 and 5 so that the activity can be completed in two 50-minute classes. We recommend that specialty group (radiation band) and synthesis group (longitude/hemisphere) assignments be made prior to, or at the start of, the first class so that students can plot their specialty data on the synthesis graph, if time permits. Getting a jump on this part of the day 2 work will leave more time for the final discussions.

Specialty group seating should be clearly marked so that groups sit together when entering the classroom. By roaming the room while student groups are working, instructors can monitor progress, answer questions and clear up any student misconceptions.

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.

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 reshuffle the maps for the second part of the activity.

Learning outcomes for unit 4:

1. Explain the physical causes for spatial variation of each of the major components of Earth's radiation balance.

• Assessed by student worksheet questions and map-based concept sketch

2. Interpret maps of radiation data to identify patterns and hypothesize their physical causes.

• Assessed by map-based concept sketch

3. Create concept sketches to effectively communicate observations and interpretations.

• Assessed by map-based concept sketch

Although students work in groups they are expected to complete their own worksheet and map-based concept sketch. Rubrics are provided for each of these components in the

Worksheet answer key and rubrics -- private instructor-only file

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PDF -- private instructor-only file

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The rubric for grading the student worksheet is included for instructors who choose to collect and grade the handout questions. In this case, it should be added to the student worksheet as well. 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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  Radiation balance exam questions

  
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Instructors may use the pre/post survey in class or as a take-home assessment tool.

• Concept Sketch Pre and Post Survey (Word) (Microsoft Word 2007 (.docx) 23kB Nov18 16), also available as a PDF (Acrobat (PDF) 42kB Nov18 16)
  

• 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.