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Claudia Kubatzki*, Martin Claussen**, Reinhard Calov, Andrey Ganopolski

Supplementary information to chapter 5.8: Modelling the end of an interglacial (MIS 1, 5, 7, 9, 11). Claudia Kubatzki*, Martin Claussen**, Reinhard Calov, Andrey Ganopolski Potsdam-Institute for Climate Impact Research PO Box 601203, 14412 Potsdam *now at Alfred Wegener Institute

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Claudia Kubatzki*, Martin Claussen**, Reinhard Calov, Andrey Ganopolski

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  1. Supplementary information to chapter 5.8:Modelling the end of an interglacial(MIS 1, 5, 7, 9, 11) Claudia Kubatzki*, Martin Claussen**, Reinhard Calov, Andrey Ganopolski Potsdam-Institute for Climate Impact Research PO Box 601203, 14412 Potsdam *now at Alfred Wegener Institute Bussestr. 24, 27570 Bremerhaven www.awi-bremerhaven.de/People/show?ckubatzk ( www.pik-potsdam.de/~kubi ) ckubatzki@awi-bremerhaven.de **now at University of Hamburg and Max Planck Institute for Meteorology

  2. Figures I This first part contains the figures of our book chapter.

  3. Figures II This second part contains supplementary material.

  4. Model: • CLIMBER-2.3 • isan Earth system model of intermediate complexity • („weather“ parameterized, coarse spatial resolution except for the inland-ice module); • couples atmosphere, ocean, vegetation, inland ice, carbon cycle; • is driven by changes in insolation and CO2; • simulation period: several thousands of years.

  5. Glacial inception: At the end of the Eemian interglacial • decreasing summer insolationin the northern hemisphere; • glacial inception in Northern America at about 117 kyBP; • bifurcation (strong positive snow-albedo feedback); • sea-level change about 40m until 100 kyBP.

  6. CO2 and insolation(Last Glacial Inception):

  7. Last Glacial Inception: 2000 years ice thickness [m] latitude latitude (Changes since Eemian) longitude longitude

  8. Last glacial inception as bifurcation (max. volume lags area by ~ 3 ky)

  9. 128 kyBP 117 kyBP 100 kyBP Atlantic ocean meridional overturning circulation

  10. 115 kyBP 125 kyBP 100 kyBP Tree fraction 10% 90%

  11. Amplification factors: • The last glacial inception in the model is mainly caused by changes in the precession. • Changes in the ocean surface as well as of vegetation provide a crucial additional, • positive albedo feedback. • Variations in the atmospheric CO2 only act as an amplification factor.

  12. Ice-area (North America): • Last Glacial Inception: • - Precession initiates • ice-sheet growth • Obliquity / CO2 • act as amplifiers Temperature (global annual):

  13. Fixed pre-ind. ... ... or Eemian surface conditions Atm.+ oce.+veg. Atm.+ oce. Atm.+ veg. Atm. interactively simulated, other components fixed

  14. Cold events: • At the end of the Eemian interglacial: • data show abrupt cooling events,and forest decline in central Europe; • reproducable in the model due to changes in the Atlantic overturning circulation, • caused by disturbing the North Atlantic freshwater balance.

  15. NGRIP members 2004 Temperature in Greenland:CLIMBER-2and NGRIP Freshwater disturbances („IRDs“) D-O events Stadials

  16. An ice-free Greenland is a possible second equilibrium state in the model • under the insolation forcing of 128 kyr BP. • Timing and extent of northern American glaciation at the end of the Eemian, • however, do not depend on the size of the Greenland ice sheet during the Eemian.

  17. Sea-level change (difference to pre-industrial): Difference between the two runs resulting from two possible equilibrium states of the Greenland ice sheet

  18. The end of the current interglacial: • In the next 50,000 years(„natural“ forcing) • only small changes in solar insolation; • insolation variations comparably low as during MIS 11 • but no significant expansion of inland ice in the model.

  19. Maximum insolation at 65oN 5 MIS 1 7 9 11 Berger 1978 CO2 from Vostok 5 MIS 7 9 11 Petit et al. 1999

  20. Height of inland ice at the end of MIS 10 (343kyBP) meters Inland-ice area Future glaciation ? Sea-level change Present 50 kyAP MIS 11 MIS 10

  21. Application of our model to a ‘typical GCM setup’: • The extent to which time-slice simulations of 115 kyr BP are able • to reproduce a transient simulation of the last glacial inception • is significantly influenced by use of a high-resolution orography • and the atmospheric CO2 concentration applied. • Certain combinations of synchronously-run periods • and acceleration of the climate model as compared to the ice-sheet module • enable a reasonable reproduction of a fully synchronous run.

  22. Annual temperature (difference to pre-industrial): the transient simulation of the fully coupled model at 115 ka BP, a time slice simulation of 115 ka BP with fixed pre-industrial ice sheets, a time slice simulation of 115 ka BP with interactive inland ice model.

  23. Global ice volume: Simulation of the last glacial inception applying different levels of climate vs. ice-sheet model acceleration (coupling period / presetting run time, the black line gives the control run).

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