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Guimberteau m 20150708_1730_upmc_jussieu_-_room_207

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Guimberteau m 20150708_1730_upmc_jussieu_-_room_207

  1. 1. matthieu.guimberteau@lsce.ipsl.fr Future changes in extreme streamflow over the Amazonian sub-basins 1119 (b) - Extreme hydrological events: deciphering changes in hazard and risk at different time-scales Matthieu Guimberteau (LSCE) J. Ronchail, J. C. Espinoza, M. Lengaigne, B. Sultan, J. Polcher, G. Drapeau, J.-L. Guyot, A. Ducharne and P. Ciais
  2. 2. matthieu.guimberteau@lsce.ipsl.fr Recent increase in discharge amplitude at Óbidos High flows Low flows Mean flows Update of Figure 2 from Callède et al. (2004, Hydrol. Sci. J.)
  3. 3. matthieu.guimberteau@lsce.ipsl.fr Ronchail et al. (2014, Env. Géomatique) Are present-time extreme discharges precursors of future conditions in the Amazon basin? Recent increase in discharge amplitude at Óbidos
  4. 4. matthieu.guimberteau@lsce.ipsl.fr ORCHIDEE Protocol
  5. 5. matthieu.guimberteau@lsce.ipsl.fr Historical meteorological forcing ORCHIDEE Control simulation (1980-2000) (Guimberteau et al., 2012, Hydrol. Earth Syst. Sc.) Protocol
  6. 6. matthieu.guimberteau@lsce.ipsl.fr Future climate change forcing Historical meteorological forcing ORCHIDEE Climate change simulations Control simulation (1980-2000) (Guimberteau et al., 2012, Hydrol. Earth Syst. Sc.) Protocol
  7. 7. matthieu.guimberteau@lsce.ipsl.fr 8 GCMs 3 emission scenarios Middle and end of the century Future climate change forcing Historical meteorological forcing ORCHIDEE Climate change simulations Control simulation (1980-2000) (Guimberteau et al., 2012, Hydrol. Earth Syst. Sc.) Climatology of GCMs outputs anomalies Delta downscaling method Protocol
  8. 8. matthieu.guimberteau@lsce.ipsl.fr 8 GCMs 3 emission scenarios Middle and end of the century Future climate change forcing Historical meteorological forcing ORCHIDEE Climate change simulations Control simulation (1980-2000) (Guimberteau et al., 2012, Hydrol. Earth Syst. Sc.) Impact of climate change on discharge Comparison Climatology of GCMs outputs anomalies Delta downscaling method Protocol
  9. 9. matthieu.guimberteau@lsce.ipsl.fr Sub-basin scale study
  10. 10. matthieu.guimberteau@lsce.ipsl.fr Sub-basin scale study
  11. 11. matthieu.guimberteau@lsce.ipsl.fr Present time Future time Relative difference (%) Runoff coefficient change P Q Rcoeff 
  12. 12. matthieu.guimberteau@lsce.ipsl.fr Number of GCMs that project a P increase (2046–2065), SRESA1B scenario Little change in average P (+1.1%) but spatial variation ! Annual P change
  13. 13. matthieu.guimberteau@lsce.ipsl.fr Number of GCMs that project a P increase in JJA (2046–2065), SRESA1B scenario Most of the GCMs simulate a P decrease in the southern regions during the dry season JJA P change
  14. 14. matthieu.guimberteau@lsce.ipsl.fr Low-flow changes
  15. 15. matthieu.guimberteau@lsce.ipsl.fr High-flow changes
  16. 16. matthieu.guimberteau@lsce.ipsl.fr Streamflow elasticity to P changes
  17. 17. matthieu.guimberteau@lsce.ipsl.fr  No change in high flow of the Amazon  Systematic discharge decrease during the recession period, leading to a 10% low-flow decrease Conclusion
  18. 18. matthieu.guimberteau@lsce.ipsl.fr  No change in high flow of the Amazon  Systematic discharge decrease during the recession period, leading to a 10% low-flow decrease  A high-flow increase is simulated in the western regions (+7%) but with low confidence  In the north, the low-flow decrease becomes higher towards the east (up to -55%) Conclusion
  19. 19. matthieu.guimberteau@lsce.ipsl.fr  No change in high flow of the Amazon  Systematic discharge decrease during the recession period, leading to a 10% low-flow decrease  A high-flow increase is simulated in the western regions (+7%) but with low confidence  In the north, the low-flow decrease becomes higher towards the east (up to -55%)  In the southern regions where the dry season would be longer and more severe (Boisier et al, 2015, Nature Clim. Change), the low flows would decrease by up to -50% in the south-east  Southern sub-basins with low runoff coefficient become more responsive to P change  Deforestation is not taken into account in our study Conclusion
  20. 20. matthieu.guimberteau@lsce.ipsl.fr Thank you for your attention
  21. 21. matthieu.guimberteau@lsce.ipsl.fr The ORCHIDEE model Land surface model LE, H, albedo, LAI ... Meteorological dataset P, Q, T, radiation...
  22. 22. matthieu.guimberteau@lsce.ipsl.fr The ORCHIDEE model Energy model + Physically based soil hydrology scheme Routing scheme Surface runoff + deep drainage Prescribed distribution of the vegetation Floodplains and swamps River discharge LE, H, albedo, LAI ... Meteorological dataset P, Q, T, radiation...

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