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Questioning estimates of CO 2 uptake by the ocean

Questioning estimates of CO 2 uptake by the ocean. Vivian Scott Supervisors: Chris Merchant, Helen Kettle. ‘Missing’ carbon sink. Atmospheric CO 2 increase less than can be accounted for. Ref: www.whrc.org. Solubility and biological pump. Source: www.whrc.org. sea surface temperature.

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Questioning estimates of CO 2 uptake by the ocean

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  1. Questioning estimates of CO2 uptake by the ocean Vivian Scott Supervisors: Chris Merchant, Helen Kettle

  2. ‘Missing’ carbon sink Atmospheric CO2 increase less than can be accounted for Ref: www.whrc.org

  3. Solubility and biological pump Source: www.whrc.org

  4. sea surface temperature CO2 transfer = solubility x gas transfer velocity x [pCO2 sea – pCO2 air] wind speed and wave type salinity, sea surface temperature, biological activity pressure and humidity CO2 concentration

  5. Mean annual net air-sea CO2 fluxfor year 1995 Takahashi et al. 2002

  6. CASIX • NERC Centre of Air-Sea Interactions and fluXes- • Reduce errors in direct ocean flux estimates • My role in CASIX: use sensitivity and uncertainty analysis techniques to study model behaviour

  7. Sensitivity analysis output parameter uncertainty range

  8. pCO2 sea • Algae fix ~ 100 Pg C annually • No shortage of CO2: nutrients, light and temperature limit growth • Models developed to study phytoplankton growth dynamics and carbon uptake

  9. Biological pump

  10. Phytoplankton modelling Equations developed by Richard Geider (Essex) and model by Helen Kettle Extensive parameterisation required- values of key parameters not well defined Using GEM-SA (Gaussian Emulation Machine for Sensitivity Analysis) to explore sensitivity and interaction of model parameters

  11. light sea water temperature nutrient chlorophyll growth carbon fixed Phytoplankton modelling CO2 dissolved CO2

  12. Future plans Apply same methods to combined General Ocean Turbulence Model (GOTM) and Hadley Centre Ocean Carbon Cycle model (HadOCC) – understand model sensitivity to help CASIX ten year hindcast

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