Interaction of physical, chemical and biological processes in atmosphere-ocean CO2 exchange in the Benguela upwelling

Lise Lotte Sørensen1, Katherine Richardson3,4, Merete B. Christiansen2, Jesper Nissen2, Søren Lund2, Lars Christensen2, Jørgen Bendtsen1, Karen Marie Hilligsøe1,3 and Lone Mouritsen3

1National Environmental Research Institute, University of Aarhus, Denmark2Risø-DTU, Denmark3University of Aarhus, Denmark4Copenhagen University

Since the world became industrialized in 1750 the atmospheric level of CO2 has risen from 270 ppm to 380 ppm.

In the same period the ocean has absorbed nearly 50% but in upwellings areas CO2 is emitted back.

As global warming increases coastal trade winds enhances (Mcgregor 2004)

Does this mean more CO2 is emitted back to the atmosphere making enhanced coastal winds an positive climate feedback process ?

Danish Galathea 3 cruise 2006-2007

ΔpCO2 measurements

Measurements of partial pressure of CO2 in Sea water and in the atmosphere using an equilibrator.

• FCO2 = SCO2 kCO2

pCO2,

Sea water is taken from continous inlet

Direct mesaurements of the flux of CO2 and detailed meteorology

High Chlorophyll concentration at 6:00

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pCO2 sea

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Namibia, 13 October 2006

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Upwelling zones: CO2 release

outward crossing high chlorophyl concentration

SOURCE

SINK

Upwelling zones: CO2 releaseNamibia, 13 October 2006

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11 O ctober 2006

Atmospheric boundary layers

Conclusions

• Clearly the interaction between the atmosphere and ocean in terms of heat exchange and physical forcing is important to the CO2 fluxes.

• Detailed description of the atmospheric flow and energy fluxes in the coastal areas are important in order to understand and estimate the CO2 fluxes in coastal upwelling regions

AcknowledgementTHANK YOU for your attention and THANKS to:

• Danish Expeditionfond

• Willum Kann Rasmussen

• Nordea Fonden

• FNU

• Knud Højgårds Fond

• Risø-DTU

• the crew on the ship ”VÆDDEREN”