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Nikki Lovenduski Department of Atmospheric and Oceanic Sciences

Carbon as Velcro: Connecting physical climate variability and biogeochemical dynamics in the Southern Ocean. Nikki Lovenduski Department of Atmospheric and Oceanic Sciences Institute of Arctic and Alpine Research University of Colorado at Boulder . Part 1: The Mean State.

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Nikki Lovenduski Department of Atmospheric and Oceanic Sciences

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  1. Carbon as Velcro: Connecting physical climate variability and biogeochemical dynamics in the Southern Ocean Nikki Lovenduski Department of Atmospheric and Oceanic Sciences Institute of Arctic and Alpine Research University of Colorado at Boulder

  2. Part 1: The Mean State

  3. Observed sea-air CO2 flux (mol m-2 yr-1) Takahashi et al. (2009) into ocean out of ocean

  4. Ocean circulation and CO2 Modified from Speer et al. (2000)

  5. Integrated (<44oS) sea-air CO2 flux into ocean data from Gruber et al. (2009)

  6. Why the model spread? Getting the physics “right” Latitude cumulative anthropogenic CO2 uptake Orr et al. (2002)

  7. Small-scale variability Anthropogenic CO2 uptake storage (mol m-2) (mol m-2 yr-1) Ito et al. (2010)

  8. Ecologists aren’t off the hook! Integrated (<44oS) sea-air CO2 flux OCMIP into ocean Dutkiewicz data from T. Ito (unpublished)

  9. Modeling the ecosystem The MAREMIP project: Phase I results SeaWiFS CCSM-BEC NEMURO PISCES Green surface chlorophyll concentration [ln(mg m-3)] data provided by M. Vogt

  10. Part 2: Variability

  11. Historical evolution of CO2 exchange

  12. Historical evolution of CO2 exchange

  13. Variability and trends in CO2 Lovenduski et al. (2008)

  14. Modes of climate variability Southern Annular Mode (SAM) El Niño – Southern Oscillation (ENSO)

  15. SAM drives CO2 flux variability spatially-integrated (<35oS), de-trended CO2fluxes CO2flux (Pg C yr-1) de-trended SAM index SAM index Lovenduski et al. (2007)

  16. SAM drives CO2 flux trend pre-industrial CO2 flux trend trend congruent with SAM Lovenduski et al. (2008) (mol m-2 yr-2)

  17. Causes of variability stronger wind stress increased meridional overturning (mmolkg-1) zonal-mean dissolved inorganic carbon Lovenduski et al. (2008)

  18. The great eddy debate Can coarse-resolution ocean models simulate an appropriate response to increasing Southern Hemisphere winds? a few references ... Hallberg and Gnadadesikan (2006) Boning et al. (2008) Hogg et al. (2008) Screen et al. (2009) Farnetiet al. (2010) Spence et al. (2010) Farneti and Gent (2011) Gent and Danabasoglu (in press)

  19. SAM drives ecosystem variability Mixed Layer Depth anomaly (+ SAM) surface chlorophyll anomaly vs. mixed layer depth anomaly Sallée et al. (2010)

  20. Part 3: Future Changes

  21. Stratification Marinov et al. (2010)

  22. Wind-driven circulation GHG Ozone Recovery SAM index • Meridional Overturning • GHG simulation • Meridional Overturning • Ozone Recovery simulation Depth (m) Sigmond et al. (2011)

  23. Acidification surface CO32- in 2100 supersaturation undersaturation CO32- = [CO32-] - [CO32-]sat Orr et al. (2005)

  24. The issues that plague us... The Mean State • How large is the Southern Ocean CO2 sink? • Can we accurately model CO2 uptake? • Accurately representing physics • Accurately representing ecology • What is the role of eddies in CO2 uptake and transport?

  25. The issues that plague us... Variability • How do eddies respond to increasing wind stress? • Can we observe variability and trends? • physical circulation • CO2 fluxes, storage • ecology

  26. The issues that plague us... Future Changes • Stratification of the Southern Ocean • Impacts on carbon storage • Impacts on ecology • Wind-driven circulation changes • Will the wind stress continue to increase? • How will this impact carbon and ecology? • How quickly will Southern Ocean acidification proceed?

  27. The End!

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