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Feng He Center for Climatic Research, UW-Madison June 26, 2013
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Testing mechanisms of the last deglaciation with transient climate simulations and high- resolution proxy data Feng He Center for Climatic Research, UW-Madison June 26, 2013 WiscSIMS Workshop - High Resolution Proxies of Paleoclimate Collaborators: Jeremy Shakun, Peter Clark, Anders Carlson Zhengyu Liu, Bette Otto-Bliesner, John Kutzbach Acknowledgements: Galen McKinley, Matt Hitchman, Jack Williams, Esther Brady, Bob Tomas, Nan Rosenbloom, Sam Levis
description
Testing mechanisms of the last deglaciation with transient climate simulations and high-resolution proxy data. Feng He Center for Climatic Research, UW-Madison June 26, 2013 WiscSIMS Workshop - High Resolution Proxies of Paleoclimate - PowerPoint PPT Presentation
Transcript of Feng He Center for Climatic Research, UW-Madison June 26, 2013
Testing mechanisms of the last deglaciation with transient climate simulations and high-resolution proxy data
Feng HeCenter for Climatic Research, UW-Madison
June 26, 2013WiscSIMS Workshop - High Resolution Proxies of Paleoclimate
Collaborators: Jeremy Shakun, Peter Clark, Anders Carlson Zhengyu Liu, Bette Otto-Bliesner, John Kutzbach
Acknowledgements: Galen McKinley, Matt Hitchman, Jack Williams, Esther Brady, Bob Tomas, Nan Rosenbloom, Sam Levis
Ice-Age Cycles
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Lisiecki and Raymo (2005)http://commons.wikimedia.org/wiki/File:Five_Myr_Climate_Change.png
Orbital Control
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Authors Year Orbital controlof LGM
Timing of LGM
Joseph Adhémar 1842 longer winter
(duration) ~10 ka
James Croll 1860s
weaker insolation in winter
(Intensity)~ 10ka
Milutin Milankovic
1930s
weaker insolation in summer
(Intensity)~22 ka
Hays, Imbrie,
Shackleton1976
Confirmed Milankovic theory with 450 kyr oxygen isotope records from the
sediments of the Southern Ocean
Problem of SH-lead
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NH Ice
SH Temp
Time
“Fly in the ointment”
Recent hypotheses for the SH-control of ice age cycles
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SH Spring Insolation
CO2-only
ICE-only
ORB-only
2007
2009
2008
Data-model comparison: testing mechanisms of the last deglaciation
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IPCC-type coupled climate model
High-res proxy data
Loutre, M. F. (2003)
Model: CCSM3 (T31_gx3v5) + dynamic vegetation
ATM 3.75(lon) x 3.75(lat) x 26(level)OCN ~3 (lon/lat) x 25 (level) Peak performance: 120 model years per day 21,000 years in 6 monthsData storage: over 300 TB
INCITE Supercomputing Support
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TraCE simulations
Transient boundary conditions
Orbital forcingGHGsIce sheetsMeltwater forcing (AMOC)
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Five simulations
Simulation ALL (ORBIT+GHG+Ice sheets+AMOC)
Simulation ORB (ORBIT)Simulation GHG (GHG)Simulation ICE (Ice sheets)Simulation MOC (AMOC)
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Ice sheet changes (once per 500 years)
He 2011
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4 Antarctic records
13 SH SST records
Transient simulation of the last deglaciation
Simulation ALL
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TraCE simulation of the SH deglaciation
Magnitude
Red: ALL forcing Blue: Orbital only
Greenland
South Atlantic
Indian Ocean
South Pacific
SH SST
Antarctic
TraCE simulation of the SH deglaciation
Timing
Red: ALL forcing Blue: Orbital only
Greenland
South Atlantic
Indian Ocean
South Pacific
SH SST
Antarctic
Bipolar seesaw
early deglacial warming in the SH
(Simulation ALL vs. single forcing simulations)
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bipolar seesaw (19-17 ka)
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Greenland
SH SST Antarctic
ORBIT-only
ICE-only
GHG-only
MOC-only
ALL
Deglacial CO2 rise
synchronous deglacial warming and eventually reach and sustain complete deglaciation
(Simulation ALL vs. single forcing simulations)
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CO2-induced global warming (17-15 ka)
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Greenland
SH SST Antarctic
ORBIT-only
ICE-only
GHG-only
MOC-only
ALL
Mechanism of the terminations
What’s causing the deglacial CO2 rise?
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Heinrich events & deglacial CO2 rise
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Deglacial CO2 rise due to Southern Ocean processes
NH meltwater
Early warming of the Southern Ocean
deglacial CO2 rise
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Large NH Ice sheets at LGM
NH meltwater
Early warming of the Southern Ocean
deglacial CO2 rise
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2006
2010
