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Southern Hemisphere Polar Climate and its “Tropical Signature” Flávio Justino Universidade Federal de Viçosa Minas Gerais, Brasil

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Presentation on theme: "Southern Hemisphere Polar Climate and its “Tropical Signature” Flávio Justino Universidade Federal de Viçosa Minas Gerais, Brasil"— Presentation transcript:

1 Southern Hemisphere Polar Climate and its “Tropical Signature” Flávio Justino Universidade Federal de Viçosa Minas Gerais, Brasil fjustino@ufv.br

2 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

3 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

4 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

5 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

6 Motivation Main Modes of Climate Variability ENSO U Illinois Justino and Peltier, JCLIM 2008 AO AAO

7 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

8 What is the LGM?

9 Antarctic Oscillation at 500hPa (Based on monthly mean values) Justino and Peltier, JCLIM 2008

10 Present Day LGM Surface Temperature Anom. [K] due to AAO+ in DJF Justino and Peltier (JCLI 2008) Surface winds Anom. [m/s]

11 Surface temperature and wind anomalies associated with AAO+ in JJA Present Day LGM Justino and Peltier (JCLI 2008)

12 Precipitation anomalies associated with AAO+ Justino and Peltier (JCLI 2008) Present Day LGM DJF JJA

13 SST anomalies associated with AAO Justino and Peltier (JCLI 2008) Present Day PEZZA AND SIMMONDS 2005

14 What About the Future?

15 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

16  1400 yrs to equilibrate. Temperature Evolution

17 Surface Temperature Anomalies

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19 14 ◦ C warming in Amundsen and Weddell Seas. Surface Temperature Anomalies

20 CO 2 Induced Sea ice Changes Justino et al. (Oecol. Bras. 2007)

21 Additional studies and grants are needed Many Thanks


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