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Southern Hemisphere Polar Climate and its “Tropical Signature” Flávio Justino Universidade Federal de Viçosa Minas Gerais, Brasil fjustino@ufv.br
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MotivationOutline Model and experimental design Coupled Model - CCSM Climate Response to Antarctic Oscillation Tropical-Polar Interaction Grip Ice Core Glacial Southern Mode - GSM CO 2 -induced Sea Ice Changes EMIC approach - LOVECLIM CO 2 –Induced Extra-tropical Climate Changes
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LGM Motivation - Ice sheet impact Justino and Peltier GRL 2005, 2006 DJF - Annular structure Sea ice extent overestimated SEAICE MARGIN Red line – GLAMAP Black Line – Present day White Line – LGM Simulation
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Motivation Why is the Holocene stable? Why was the Last Glacial Period unstable? Can abrupt changes occur during the „Anthropocene“ ? Ganopolski & Rahmstorf (2001) Holocene LGM
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Motivation - Present Day Sea ice Changes a Annual Mean (-2,7% decade- 1 ) Annual Mean (0.5 % decade- 1 no significant) Summer Minimum (-7,4% decade- 1 ) IPCC 2007
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Motivation Main Modes of Climate Variability ENSO U Illinois Justino and Peltier, JCLIM 2008 AO AAO
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What is the NCAR-CSM 1.4 Model? Atmosphere-Land component - Full GCM, T31 (3.75 x 3.75 ° ) - 18 layers (top at 10hPa) - Soil moisture, 28 vegetated surfaces Ocean-sea-ice component - Ocean general circulation model - 3 x 3 ° horizontal resolution - 25 vertical levels Ocean-sea-iceAtmosphere-Land Exchange Momentum, freshwater, and heat
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What is the LGM?
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Antarctic Oscillation at 500hPa (Based on monthly mean values) Justino and Peltier, JCLIM 2008
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Present Day LGM Surface Temperature Anom. [K] due to AAO+ in DJF Justino and Peltier (JCLI 2008) Surface winds Anom. [m/s]
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Surface temperature and wind anomalies associated with AAO+ in JJA Present Day LGM Justino and Peltier (JCLI 2008)
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Precipitation anomalies associated with AAO+ Justino and Peltier (JCLI 2008) Present Day LGM DJF JJA
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SST anomalies associated with AAO Justino and Peltier (JCLI 2008) Present Day PEZZA AND SIMMONDS 2005
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What About the Future?
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Model: LOVECLIM Earth Model of Intermediate Complexity Initial Conditions: anthropogenic greenhouse gases 500, 600, 700 and 800ppm of CO 2 + CH 4, N 2 0, O 3
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1400 yrs to equilibrate. Temperature Evolution
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Surface Temperature Anomalies
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14 ◦ C warming in Amundsen and Weddell Seas. Surface Temperature Anomalies
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CO 2 Induced Sea ice Changes Justino et al. (Oecol. Bras. 2007)
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Additional studies and grants are needed Many Thanks
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