PALEOCLIMATE PROXIES & EL NIÑO SOUTHERN OSCILLATION

Megan F. GambsUW Oceanographymfgambs@uw.edu

UWHS Atmospheric Sciences 211May 2013 Workshop

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• PALEOCLIMATE PROXY =– any “biological, physical, or chemical

measurement made in: • sediments,• fossil shells, • ice cores,• trapped air, • speleothems, • corals, and other archives

– that serve as surrogates for climate parameters…”

WHAT IS A CLIMATE PROXY?

Thomas Cronin; USGS

\EXAMPLES OF PALEOCLIMATE PROXIES

http://www.ncdc.noaa.gov/paleo/image/collage/paleoproxycollage.jpg

El NiÑO Southern OSCILLATION

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• Coral Skeletons are made of CaCO3.–We can analyze two ratios: • Oxygen isotopes (16-O to 18-O)

– Tells us about water temperature

• Ratio of Magnesium to Calcium (Mg/Ca)– Tells us about salinity

» This gives information about precipitation

WHAT CAN CORALS TELL US?

Thomas Cronin; USGS

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• El Niño vs. Normal

EL NIÑO SOUTHERN OSCILLATION (ENSO)

http://www.pmel.noaa.gov/tao/elnino/nino_normal.html

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• La Niña vs. Normal

EL NIÑO SOUTHERN OSCILLATION (ENSO)

http://www.pmel.noaa.gov/tao/elnino/nino_normal.html

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• El Niño vs. La Niña

EL NIÑO SOUTHERN OSCILLATION (ENSO)

http://www.pmel.noaa.gov/tao/elnino/nino_normal.html

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• El Niño vs. La Niña

EL NIÑO SOUTHERN OSCILLATION (ENSO)

http://www.pmel.noaa.gov/tao/elnino/nino_normal.html

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• El Niño vs. La Niña

EL NIÑO SOUTHERN OSCILLATION (ENSO)

http://www.pmel.noaa.gov/tao/elnino/nino_normal.html

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• How do corals help with our understanding of ENSO?

Corals & ENSO: Introduction

Prof. Sandy Tudhope; University of Edinburgh, School of Geosciences

\ “coring” a living Porites coral

Photo credits: USGS (above ), A. Tudhope (right)

\ CORALS & ENSO: STUDY AREA IN PAPUA NEW GUINEA

http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/eln/def.rxml

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• Use δ18O records extracted from corals, as published in Science (Tudhope et al. 2001)

• Employ Excel to create plots of properties through time, from the corals

• Goal: illustrate the relationship between δ18O recorded in corals and modern El Nino events– Use this relationship to reconstruct El Nino

events in the “paleo record”

CORALS & ENSO: THE ACTIVITY

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• (1) Modern Corals– Compare the living coral data to modern

SST measurements

• (2) Ancient Corals– Now, that you’ve proved that del18O

records track ENSO events (variations in precipitation and temperature), study ENSO back in time.

CORALS & ENSO: THE ACTIVITY

\PALEO: CORALS & ENSO

*

\ENSO & CORALS: ANCIENT CORALSFROM HUON PENINSULA, PAPUA NEW GUINEA

Photo credit: Prof. Sandy Tudhope

Raised Coral Reef Terraces

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• (1) Modern Corals– Compare the living coral data to modern

SST measurements

• (2) Ancient Corals– Now, that you’ve proved that del18O

records track ENSO events (variations in precipitation and temperature), study ENSO back in time.

CORALS & ENSO: THE ACTIVITY

\MODERN: CORALS & ENSO

http://www.ncdc.noaa.gov/paleo/pubs/tudhope2001/tudhope.html

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• This presentation can be found at the following website: http://www.uwpcc.washington.edu/outreach/tertiary.jsp?entity=NASA&action=GetEntity&title=NASA/UWHS%20Climate%20ScienceOr, http://tinyurl.com/oqo8ml7

• *Timeseries presented, here, are sourced from http://www.ncdc.noaa.gov/paleo/pubs/tudhope2001/tudhope.html and are based on published work by Tudhope et al. 2001.

• Alexander W. Tudhope, Colin P. Chilcott, Malcolm T. McCulloch, Edward R. Cook, John Chappell, Robert M. Ellam, David W. Lea, Janice M. Lough, and Graham B. Shimmield. Variability in the El Niño-Southern Oscillation Through a Glacial-Interglacial Cycle. Science, v.291(5508), pp 1511-1517, February 23, 2001