ArgoOxygen Program Overview

1
Argo-Oxygen Program Overview

• White paper produced by writing team lead by
  Nicolas Gruber
• Scientific justification for measuring
  sub-seasonal to decadal O2 changes
• O2 is rather sensitive to changes in circulation
  and biology
• Subsurface O2 changes are an indication of
  oceanic export production
• Important to understand ocean O2 outgassing for
  interpretation of the atmospheric O2 record
• New sensor technology means drift and accuracy
  can be within the required limits

2
Argo-Oxygen Program update

• White paper presented to the AST-8 in March
• Well received AST supported Dr Grubers propsal
  for a coordinated pilot study
• AST concerned over the effect on battery life,
  float failure rates, cost, and implications for
  current legal agreements
• For the pilot study, it was agreed that SIC would
  oversee the project for the next phase and that
  Dr Gruber will continue to lead the Argo-Oxygen
  team.

3
Technical issues

• Choice of floats (ARGOS vs Iridium)
• CTD pumps, data upload rates
• Sensors types (IDO vs Optode)
• Accuracy, drift
• Adding O2 reduces battery life by 10-30 (can be
  compensated by more efficient Seabird CTD pump)
• Increased cost (inc. sensors, data transfer) is
  20-30, and around 40 when reduced float
  lifetime is taken into account

4
Implementation Phase

• Deploy around 100 floats in a concentrated area
  of scientific interest (i.e. Nth Atlantic, Nth
  Pacific)
• Cost for 2 years of floats 2.5M ship time
  regular Winkler titrations from ships to validate
  float obs
• Integrate pilot study with i.e. biogechemical
  modelling studies to estimate export production