Changes in Carbon uptake
and emissions by Oceans
in a changing climate
(CARBOCHANGE)
Dr Pedro M.S. Monteiro
Dr Nicolas Fauchereau
Council for Scientific and Industrial Research
Support event on climate change
research Cooperation
Pretoria, 12/09/2011
OUTLINE
Background: Southern Ocean and CO2
Areas of contributions and SA-EU collaborations
1) long-term monitoring and understanding of biogeochemical processes in the SO: in-situ observations
2) understanding the sensitivity of the CO2 fluxes to
Climate (variability and changes): in-situ, Satellite
Remote Sensing, Modelling
3) developing SA Modelling capability
Why the Southern Ocean ?
Northern
Hemisphere
Southern
Hemisphere
NASA, SeaWIFS
• The Southern Ocean has taken up ~40% of anthropogenic CO2 (CO2 SINK)
• It is the only part of the ocean where CO2 rich deep waters (> 2000m & pCO2 >
450µatm) exchange CO2 directly with the atmosphere
• Mode Water and Intermediate Water formed in the Southern Ocean flows into the
low latitudes and is responsible for the supply of nutrients that drive > 75% of ocean
productivity
• Has been experiencing large changes over the past few decades
1) In Situ Observations:
Long-Term Monitoring
● Process studies
● The future ...
●
Ship-based measurements
Gough Is:
South: Sep
North: Oct
Marion Is:
South: April
North: May
Scotia Sea:
North: Jan - Feb
South: Feb
SANAE:
South: Dec
North: Mar
SA Agulhas
Contribution to SOCAT
Surface Ocean CO2 Atlas
Process Studies
Physics
• Temperature (UCT, CTD, XBTs)
• O-A fluxes ...
Trace metal
• Iron
Chemistry
• NO3, NH4, urea, PO4, SiO4
• Dissolved Oxygen
• Salinity
• TCO2, total alkalinity
Biology
• Chlorophyll-a
• Pigments (HPLC)
• Size distribution
• Microscopy
• 15N Primary Production
• POC / PON
• SEM
The Future ...
●
The SA Agulhas II
●
National Ocean Glider Facility
●
Bio-Optical capability
SOSCEx 2012
2-3 months
October - December - April
Gough Is.
9/12/11
SRP Proposal
2) Sensitivity of CO2 fluxes to
changes in climate:
Focus:
Biological pump (phytoplankton)
● Role of the Mixed-Layer Dynamics
● Seasonal Cycle
●
In-situ observations (ship, ARGO), Satellite Remote Sensing, Modelling ...
Exemple
Collaboration CSIR, UCT, Laboratoire des Sciences du Climat et de
L'Environnement (LSCE, France)
Fauchereau N., Tagliabue A., Bopp L., Monteiro P.: The response of
phytoplankton biomass to transient mixing events in the Southern
Ocean, Geophysical Research Letters, July 2011
Satellite Ocean Color, SST, Reanalysis, NEMO-PISCES (Ocean – Biogeochemistry)
The response of phytoplankton biomass to transient mixing anomalies is
dependent upon the balance between light and iron limitation, mediated by seasonal
ML changes
Response of Primary Production to changes in upper Ocean stratification depends
on the time-scales considered (intra-seasonal, seasonal, interannual)
3) Numerical Modelling:
Focus:
Coupled Ocean - Biogeochemistry
● Mixed-Layer-Dynamics
● Meso-scale and subseasonal variability
●
Mixed-Layer-Dynamics controls availability of light, nutrients and the
characteristics of Carbon export to depth
Important
Forcing
Momentum
E-P
Heat
Important
Processes
Must be resolved
Or parameterized
In the model
http://hpl.umces.edu/ocean/sml_main.htm
Meso-scale eddies and processes increasingly recognized as
important in dictating patterns of Primary Production
Kahru et al, GRL 2007
Implementation of coupled model NEMO – PISCES
at the Centre for High Performance Computing (Cape-Town)
NEMO: Nucleus for European Modelling of the Ocean
PISCES: Pelagic Interaction Scheme for Carbon and Ecosystem Studies
Physical model (NEMO)
What effect do meso-scale processes have on the surface mixed layer?
●
●
Ecosystem and carbon cycle model (PISCES)
What is the response in production and carbon export?
CONCLUSIONS
CARBOCHANGE instrument of:
Unique contribution of South Africa to global knowledge and understanding of the
Carbon Cycle in the Southern Ocean (geographical advantage !)
●
●
Active collaborations with European colleagues (joint publications in top journals)
Technology transfer (European experience in coupled Ocean-biogeochemical
modelling)
●