a model for investigating sun-climate questions e.j. zita and gerardo chin-leo the evergreen state...

A model for investigating Sun-climate questions

E.J. Zita and Gerardo Chin-Leo

The Evergreen State College

Olympia, WA 98505

<[email protected]> and <[email protected]>

Presented at SORCE meeting on Paleo Connections Between the Sun, Climate, and Culture

14-16 Sept 2005, Durango CO

http://lasp.colorado.edu/sorce/2005ScienceMeeting/

http://lasp.colorado.edu/sorce/2005ScienceMeeting/

Abstract

We develop a model for investigating Sun-climate questions in an interdisciplinary college classroom. A solar physicist and an biological oceanographer will work together in 2006 to identify key open questions suitable for analysis by undergraduates, in an integrated academic program on climate change. We will motivate investigations by reading current peer-reviewed articles. Teams of students will analyze data on each question and produce a tutorial which synthesizes best current understanding. For example, what is the evidence for climate changes on the Gleissberg cycle (and other cycles)? Are apparent historical correlations between sunspot maxima and Earth temperature changes consistent with the period shifts in the relative brightness of faculae? What is the role of ocean circulation in controlling Earth temperatures? How do historical indicators of shifts in ocean circulation compare to effects of solar variability on Earth?

We welcome your ideas or requests for data analysis. Evergreen science students have a strong record of contribution to basic and applied research, from energy transport by solar magnetohydrodynamic waves to study of plankton's effects on ocean albedo.

Investigating Sun-Climate questions, Zita, SORCE, 14-16 Sept 2005, Durango, CO

Outline

• Evergreen: Interdisciplinary studies

• Fire and Water program, Fall 2006

• Water: Oceans affect climate (Gerardo)

• Fire: Sun affects climate (Zita)

• Student research on real questions (your questions?)

• Anticipated outcomes


Evergreen: Interdisciplinary studies

The Evergreen State College promotes student learning through:

Interdisciplinary StudyStudents learn to pull together ideas and concepts from many subject areas, which enables them to tackle real-world issues in all their complexity.Collaborative LearningStudents develop knowledge and skills through shared learning, rather than learning in isolation and in competition with others.Learning Across Significant DifferencesStudents learn to recognize, respect and bridge differences - critical skills in an increasingly diverse world.Personal EngagementStudents develop their capacities to judge, speak and act on the basis of their own reasoned beliefs.Linking Theory with Practical ApplicationsStudents understand abstract theories by applying them to projects and activities and by putting them into practice in real-world situations.


Fire and Water, Fall 2006

Over geologic time the Earth has experienced wide fluctuations in climate, such as ice ages. Earth is currently experiencing a rapid warming trend. A major factor determining global climate is the intensity of the Sun's energy reaching the Earth. However, climate changes cannot be explained by variations in solar radiation alone. Climate changes involve complex interactions between astronomical and Earth-bound processes. This program will examine some of these interactions. Specifically, we will examine how the Sun's output has varied over geologic time and recently. We will also examine how the oceans impact global climate by redistributing the Sun's energy and affecting the composition of the atmosphere. We will discuss how changes in ocean circulation may explain climatic changes over geologic time. We will also study how marine microorganisms play a major role in the cycling of gases that affect climate. Finally, we will discuss contemporary global warming, examining the contribution of human activities and fluctuations in solar output. We will critique proposed schemes to engineer solutions to global warming such as the sequestration of anthropogenic carbon into the deep sea.

Our study will examine various physical, chemical, geological and biological processes. This requires a basic understanding of biology and chemistry as well as facility with algebra and an ability to learn pre-calculus. The material will be presented through lectures, workshops, laboratories and seminars. We will draw on the primary literature whenever possible for a rigorous scientific treatment of this topic. Students will do significant teamwork and will research in depth questions of particular interest. We will have weekly online assignments, so students should be comfortable using computers and the Internet.

Credit awarded in introductory physics, earth science, marine science, and environmental studies.

http://academic.evergreen.edu/curricular/fireandwater/


Water: Ocean biology affects climate

• Phytoplankton production is an important sink of atmospheric CO2. Sinking of phytoplankton biomass below the pycnocline (“biological pump”) removes CO2 from atmospheric circulation.

• Phytoplankton are important producers of DMS (dimethylsulfide). This sulfurcompound contributes to the formation of cloud condensation nuclei that affect the Earth’s radiative budget.


Ex: Oceans affect climate

Plankton contribute to absorption and emission of CO2, cloud formation, ocean albedo, and more.

Thermohaline cycle transports energy globally.


Fire: Solar irradiance affects climate

Pro: Greater solar irradiance L๏ → warmer Earth, right?

Con: Faint young Sun paradox (warm young Earth due to atmospheric/ocean effects?)

Pro: Maunder Minimum, Mideval Maximum, …

Con: Correlation or cause? Phase shift: sunspots║higher L๏ now, but lower L๏ in past

Pro: Changes in Earth’s orbit or tilt → changes in L๏ → changes in TE (spectral analysis - Milankovich cycles)

Many outstanding questions about proxies, correlations, and mechanisms.


Student research on real questions

1. Motivate student interest

2. Learn background concepts

3. Teams choose research questions

4. Facilitate student research

5. Student teams present and publish results


1. Motivate student interest

Seminar on high quality, accessible articles, such as:• Living with a Variable Sun, J. Lean, Physics Today, 58, 32, June 2005

• The Sun’s Role in Climate Variations, D. Rind, Science, 296, 673, 26 April 2002

• Intergovernmental Panel on Climate Change (IPCC)

• Will marine DMS emissions amplify or alleviate global warming? Bopp et al., Can.J.Fish.Aquat.Sci./J.Can.Sci.Halieut.Aquat., 61, 2002

• Influence of equatorial diatom processes on Si deposition and atmospheric CO2 cycles at glacial/interglacial timescales, Dugdale et al., Paleoceanography, 91, 2004

• Persistent Solar Influence on North Atlantic Climate During the Holocene, Gerard Bond, Bernd Kromer, Juerg Beer, Raimund Muscheler, Michael N. Evans, William Showers, Sharon Hoffmann, Rusty Lotti-Bond, Irka Hajdas, and Georges Bonani Science 7 December 2001; 294: 2130-2136; published online 15 November 2001 [DOI: 10.1126/science.1065680]

• A Pervasive Millennial-Scale Cycle in North Atlantic Holocene and Glacial Climates, Gerard Bond, William Showers, Maziet Cheseby, Rusty Lotti, Peter Almasi, Peter deMenocal, Paul Priore, Heidi Cullen, Irka Hajdas, and Georges Bonani Science 14 November 1997; 278: 1257-1266 [DOI: 10.1126/science.278.5341.1257]


Ex: Motivating student interest…

Friis-Christensen & Lassen (1991) Lean & Rind (2002) Lean & Rind (2001)

Evergreeners studying phytoplankton in local estuaries

2. Background concepts

Interactive workshops will develop understanding on basic concepts such as:

• Scientific method, correlation vs cause, testing predictions, …• Biological oceanography: biogeochemical cycles, phytoplankton ecology

& physiology• Physics: forces, energy, heat flow, fluid motion, …• Math: cycles, nonlinearity, computer modeling, …• Measurement: spectra, isotope proxies, plankton density, …• Atmosphere: convection, Hadley cells, …• Ocean: T and salinity gradients, global conveyor belt, …• Radiation and albedo: plankton, clouds, ice, …• Carbon sources and sinks: plankton, trees, ocean warming,…• Orbits, precession, nutation, Milankovich cycle, …• Gaia hypothesis (forcing, equilibrium & stability)


Ex: Background concepts


Thermohaline cycle Fluid flows and energy flux Milankovitch cycle

3. Candidate research questionsWhat is the evidence for / mechanism of (choose a cycle): 11 years (sunspots), 22

years (solar B field), 88 yr (Gleissberg: moon connection? Jose Rial), ~210 yr (Suess), 1500 yr (ocean interaction), 23 ky (precession), 40 ky (nutation), 100 ky (eccentricity)

Maunder Minimum, Medieval Maximum, faint young Sun paradox, …

(How) can small changes in L๏ cause large changes in TE?

What is the evidence for (how often, how recent …is) this process:Warming →ice melting →damped ocean circulation →cooling

What is the role of plankton in climate change: carbon sequestration, dimethylsulfide & clouds, albedo, …

How do changes in phytoplankton species composition affect the rate of CO2 removal and DMS production?

Can atmospheric CO2 be removed effectively by fertilizing oceans? Side effects?

Is there a connection between lake levels and rainfall at Lake Victoria? (Boyd and Schatten, pp.115, 132-134; Curt Stager)


Ex: Candidate research questions

Suggest your question here. Data for students to analyze?


4. Teams investigate research questions

Literature search: find and read references.

Discuss with team and faculty, deepen understanding.

Articulate hypotheses to address your question.

Find and analyze data, test your hypotheses.

Examine societal consequences.

Summarize learning in a research report.

Present tutorial in class, publish on class web pages.

Synthesize knowledge between teams → big picture.


Examples of student research


Oceans and Plankton Physics & Astronomy

5. Presenting & publishing results

Teams draft research reports.

Submit them to class for peer review.

Present tutorials to class.

Seminar on tutorials to synthesize a broader view.

Present at local meetings, such as Evergreen Science Fair, American Physical Society (NW section), AAPT, AAS

Ambitious students draft articles for submission to refereed journals.


Anticipated outcomes

• Analyze existing data

• Contribute to investigation of open questions

• Train & recruit new scientists

• Increase public scientific literacy

• Research results online


Acknowledgements

We acknowledge support from the Evergreen State College in the form of summer program planning time,

And we thank the facilitators of the Faculty Institute on Web Tools for their technical assistance.


References and sources of figures

Shindell et al. (http://www.people.virginia.edu/%7Emem6u/ssmrw02.html)

Robert Stewart (http://oceanworld.tamu.edu/NMEA_Talk/NMEA_Talk_2004.html)

ETE team (http://www.cotf.edu/ete/modules/coralreef/CRatmo.html)

Judith Lean and David Rind, Sun-Climate Connections: Earth's Response

to a Variable Sun, Science, Vol 292, Issue 5515, 234-236 (2001)

Friis-Christensen, E.; Lassen, K., Science, 254, 698-700 (1991)

D. Rind (courtesy of J. Lean), The Sun's Role in Climate Variations

Science, Vol 296, Issue 5568, 673-677 (2002)


http://www.people.virginia.edu/%7Emem6u/ssmrw02.html

http://oceanworld.tamu.edu/NMEA_Talk/NMEA_Talk_2004.html

http://www.cotf.edu/ete/modules/coralreef/CRatmo.html

http://adsabs.harvard.edu/cgi-bin/author_form?author=Friis-Christensen,+E&fullauthor=Friis-Christensen,%20E.&charset=UTF-8&db_key=AST

http://adsabs.harvard.edu/cgi-bin/author_form?author=Friis-Christensen,+E&fullauthor=Friis-Christensen,%20E.&charset=UTF-8&db_key=AST

http://adsabs.harvard.edu/cgi-bin/author_form?author=Lassen,+K&fullauthor=Lassen,%20K.&charset=UTF-8&db_key=AST

References …

The Earth Institute, Columbia University (http://www.earth.columbia.edu/news/2005/images/conveyor_belt.gi)

Atelier Changement Climatique, ENPC (http://www.enpc.fr/fr/formations/ecole_virt/trav-eleves/cc/cc0304/cycle-carbone/cycle-carbone.htm)

Richard Dewey, UVic, BC

(http://web.uvic.ca/~rdewey/eos110/webimages.html)

Scott Rutherford, Roger Williams Univ., RI, Milankovitch Cycles in Paleoclimate, (http://deschutes.gso.uri.edu/~rutherfo/milankovitch.html)

E.J. Zita, solar physics research at Evergreen and HAO/NCARhttp://academic.evergreen.edu/z/zita/research.htm, http://www.hao.ucar.edu/


a model for investigating sun-climate questions e.j. zita and gerardo chin-leo the evergreen state...

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climate questions

climate changes

climate gerardo

global climate

climate zita student

real questions

evergreen science students

teams of students