Transcript A model for investigating Sun-climate questions

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
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 peerreviewed 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
Investigating Sun-Climate questions, Zita, SORCE, 14-16 Sept 2005, Durango, CO
Evergreen: Interdisciplinary studies
The Evergreen State College promotes student learning through:
Interdisciplinary Study
Students learn to pull together ideas and concepts from many subject areas,
which enables them to tackle real-world issues in all their complexity.
Collaborative Learning
Students develop knowledge and skills through shared learning, rather than
learning in isolation and in competition with others.
Learning Across Significant Differences
Students learn to recognize, respect and bridge differences - critical skills in an
increasingly diverse world.
Personal Engagement
Students develop their capacities to judge, speak and act on the basis of their
own reasoned beliefs.
Linking Theory with Practical Applications
Students understand abstract theories by applying them to projects and
activities and by putting them into practice in real-world situations.
Investigating Sun-Climate questions, Zita, SORCE, 14-16 Sept 2005, Durango, CO
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/
Investigating Sun-Climate questions, Zita, SORCE, 14-16 Sept 2005, Durango, CO
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 sulfur
compound contributes to the formation of cloud
condensation nuclei that affect the Earth’s
radiative budget.
Investigating Sun-Climate questions, Zita, SORCE, 14-16 Sept 2005, Durango, CO
Ex: Oceans affect climate
Plankton contribute to absorption and emission of CO2,
cloud formation, ocean albedo, and more.
Thermohaline cycle transports energy globally.
Investigating Sun-Climate questions, Zita, SORCE, 14-16 Sept 2005, Durango, CO
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.
Investigating Sun-Climate questions, Zita, SORCE, 14-16 Sept 2005, Durango, CO
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
Investigating Sun-Climate questions, Zita, SORCE, 14-16 Sept 2005, Durango, CO
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]
Investigating Sun-Climate questions, Zita, SORCE, 14-16 Sept 2005, Durango, CO
Ex: Motivating student interest…
Friis-Christensen & Lassen (1991)
Lean & Rind (2002)
Evergreeners studying phytoplankton in local estuaries
Lean & Rind (2001)
2. Background concepts
Interactive workshops will develop understanding on basic
concepts such as:
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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)
Investigating Sun-Climate questions, Zita, SORCE, 14-16 Sept 2005, Durango, CO
Ex: Background concepts
Thermohaline cycle
Fluid flows and energy flux
Investigating Sun-Climate questions, Zita, SORCE, 14-16 Sept 2005, Durango, CO
Milankovitch cycle
3. Candidate research questions
What 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)
Investigating Sun-Climate questions, Zita, SORCE, 14-16 Sept 2005, Durango, CO
Ex: Candidate research questions
Suggest your question here. Data for students to analyze?
J.Curt Stager, Lake Victoria levels, rainfall, and solar irradiance, in and out of
correlation due to ENSO? Phase shift due to changing sunspot/faculae ratio?
Debbie Sherrer, Stanford Solar Center (EPO) – radio signals in ionosphere
Ray Bradley and Michael Mann – compare data to T(t) hockey stick
Jose Rial - Eccentricity oscillations due to interaction between Earth’s orbits with
moon & planets → Gleissberg cycle? Science 1999, GRL 1995
Julia Saba – pre-solar max jumps in Xray and EUV – compare to Dikpati/Zita
solar dynamo simulations – under what conditions does poloidal flux
rapidly rise to photosphere?
Plankton Mg/Ca combined with d18O to reconstruct past T, salinity (Lund,
Investigating Sun-Climate questions, Zita, SORCE, 14-16 Sept 2005, Durango, CO
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.
Investigating Sun-Climate questions, Zita, SORCE, 14-16 Sept 2005, Durango, CO
Examples of student research
Oceans and Plankton
Physics & Astronomy
Investigating Sun-Climate questions, Zita, SORCE, 14-16 Sept 2005, Durango, CO
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.
Investigating Sun-Climate questions, Zita, SORCE, 14-16 Sept 2005, Durango, CO
Anticipated outcomes
• Analyze existing data
• Contribute to investigation of open questions
• Train & recruit new scientists
• Increase public scientific literacy
• Research results online
Investigating Sun-Climate questions, Zita, SORCE, 14-16 Sept 2005, Durango, CO
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.
Investigating Sun-Climate questions, Zita, SORCE, 14-16 Sept 2005, Durango, CO
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)
Investigating Sun-Climate questions, Zita, SORCE, 14-16 Sept 2005, Durango, CO
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/cyclecarbone.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/NCAR
http://academic.evergreen.edu/z/zita/research.htm, http://www.hao.ucar.edu/
Investigating Sun-Climate questions, Zita, SORCE, 14-16 Sept 2005, Durango, CO
Followup
Ray Bradley, UMass Amherst, IPCC <[email protected]> (+ Michael Mann, hockey stick) T(t) data
Charles Perry, USGS, Lawrence, KS <[email protected]> model connecting solar variability with Mississippi
flooding: http://ks.water.usgs.gov/Kansas/waterdata/climate/
Curt Stager, Paul Smith’s College, NY <[email protected]> Solar variability and rainfall at Lake Victoria,
East Africa: http://webpages.paulsmiths.edu/~stagerj/website.html
Peter deMenocal <[email protected]>, Columbia, NY – Late Holocene variability of Atlantic surface
and deep ocean circulation, cf Bond et al. article, Science 2001 (Planktons as proxies)
Jose Rial [email protected] , UNCarolina & CIRES at UCBoulder– Lunar influence on Gleissberg cycle?
-Earth's orbital eccentricity and the rhythm of the Pleistocene ice ages: the concealed pacemaker, 2004 Global and
Planetary Change, v. 41, iss. 2, p. 81-93.
- Abrupt climate change: chaos and order at orbital and millennial scales, 2004, Global and Planetary Change, v.
41, iss. 2, p. 95-109.
David Lund, MIT/Woods Hole <dlund@whoi@edu>, Gulf stream variability during the last millenium –
increased L -> more evaporation in Gulf Stream WOW, increased salinity during Maunder Min., centennial
droughts. Cf Haug et al., Southward Migration of the Intertropical Convergence Zone Through the Holocene,
Science, Volume 293, Issue 5533, pp. 1304-1308 (2001). (Planktons as proxies)
Paul Mayewski <[email protected]>, Climate Change Institute (http://www.ume.maine.edu/iceage/),
U.Maine, Polar ice cores, student learning resources (http://www.secretsoftheice.org/learning/index.html)
Investigating Sun-Climate questions, Zita, SORCE, 14-16 Sept 2005, Durango, CO