1 / 29

Kaplan et al. 2003

LGM model simulations. ... vs. reconstructions. Kaplan et al. 2003. Mid-Holocene model simulations. ... vs. reconstructions. BIOME 6000 reconstruction (Prentice, Webb et al., 1999). today. mid-Holocene. Neolithic Rock Painting (Tassili-Plateau, Sahara). Insolation change.

doris
Télécharger la présentation

Kaplan et al. 2003

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. LGM model simulations ... vs. reconstructions Kaplan et al. 2003

  2. Mid-Holocene model simulations ... vs. reconstructions

  3. BIOME 6000 reconstruction (Prentice, Webb et al., 1999) today mid-Holocene

  4. Neolithic Rock Painting (Tassili-Plateau, Sahara)

  5. Insolation change

  6. High northern latitudes: Amplification of snow-albedo feedback by sea ice-albedo feedback GDD0 [oC] Transient model runs: tree fraction carbon storage [kgC/m2]

  7. Transient model runs

  8. Abrupt desertification Insolation northern hemisphere Monsoon rain, Northern Africa Vegetation Sahara Reconstruction B,C – CLIMBER-2 results Claussen et al., 1999 D – proxy data deMenocal et al., 2000

  9. CLIMBER Precipitation differences (NH Summer) mid-Holocene - present Niederschlagsdifferenzen (NH Sommer) mittleres Holozän - heute DP(mm/d)  Amplification of monsoonal precipitation by local ‚recycling‘

  10. Complex-model simulations of LGM: two equilibrium states (depending on initial vegetation conditions)

  11. Present-day Mid-Holocene LGM

  12. Simplified model:

  13. Conceptual model: V 2 equil green 1 V*(P) P*(V) P 0 desert Stability function Mid-Holocene 2xCO2 V 1 Modern desert green Brovkin et al. 1998

  14. Practical units • Daisyworld • Multiple equilibria • ...

  15. Climate forcing • Natural • ->Sun • Anthropogenic • ->Emission of greenhouse gases ... ->Volcanism ->Land use

  16. Effect of deforestation: biogeophysical biogeochemical sum

  17. Ruddiman‘s Hypothesis: Ruddiman 2003

  18. Cox et al. 2004

  19. Betts et al. 2004

  20. Will greenhouse greenthe Sahara? (Petit-Maire, 1990) [ppmv] Scenarios of atmospheric CO2 concentration Vegetation fraction in the Sahara Claussen et al., 2003 years of simulation

  21. mid-Holocene 2 x CO2 DTJJA DPJJA Claussen et al., 2003

  22. Northern Africa (JJA) ‘Hadley‘ ‘Monsoon‘ near-surface spec. humidity dynamic + thermodyn. component (of changes in vertical moisture flux) Claussen et al., 2003

  23. Biosphere 2:

More Related