Bio-Argo status pilot projects

planning

Oceanography (2009)

« Bio-Argo » Community White Paper, « Integrated Bio-platform» Plenary Paper

Progressive organization of The “Bio-Argo” community

Session and Town Hall meeting : Development of a Global Ocean Biogeochemical Observing System Based on Profiling Floats and Gliders

Toward the Implementation of a Global Autonomous Biogeochemical Observing System, WHOI, June 2011

• SCOR UNESCO Working Group 142 “Quality Control Procedures for Oxygen and Other Biogeochemical Sensors on Floats and Gliders”. (Körtzinger & Johnson) March 1st

• ADMT 15, November 2013, Liverpool, 2-day Bio-Argo

• Session at Ocean Science Meeting 2014: Towards a Global Ocean Biogeochemical Observing System Based on Profiling Floats and Gliders (Claustre & Johnson): 25 abstracts

Progressive organization of The “Bio-Argo” community

• Tutorial (30 ‘ talk) at Ocean Science Meeting 2014: Towards a Global Ocean Biogeochemical Observing System Based on Profiling Floats (Johnson, Claustre & Sarmiento)

Beside O2, the biogeochemical community has identified the first variables ready to be implemented

Nitrate : New production (build up of organic material) ; remineralization; potential for being a core variable for GCM/biogeochemical.

Oxygen: exchange with atmosphere, marine photosynthesis and respiration.

Particulate backscattering : Stock of particulate matter (detrital and living). Proxy of Particulate Carbon. required by spatial agencies (OCR) potential for being a core variable for GCM/biogeochemical.

Chlorophyll a : Proxy of phytoplankton biomass, photosynthesis; required by spatial agencies (OCR); potential for being a core variable for GCM/biogeochemical.

Selection of these variables through an international consensus : IOCCG Working group“Bio-optical sensors on Argo floats Argo”, OceanObs09

pH (total) 25 C

7.2 7.4 7.6 7.8 8.0

Depth

(m

)

0

200

400

600

800

1000

1200

1400

1600

1800

Float 7672

HOT 2009/11

Float 8514

Deep-Sea Durafet pH sensors now operating on floats

Other variables on their way to become mature

Radiometry PAR: Photosynthetically Available Radiation (400-700 nm). Photosynthesis

(euphotic zone). Heat deposition (?) Downwelling irradiance (Eds) => derive Kds robust products (e.g. insensitive to

drift) to refine retrieval of Chla and CDOM. Great potential for CAL-VAL activities (OCR).

pH: Great potential for a global array

CDOM: Water mass tracer (coastal, melting ice). CAL-VAL of OCR

Transmissiometry cp : Proxy of phytoplankton biomass, Precise measurement useful for flux (primary production, exportation at depth) estimata.

Some BGC float exemples

NAVIS PROVOR

NO3

O2

Eds (l) PAR

O2

APEX

Chla bp

O2

Eds (l)

Cp(660)

CDOM Chla bbp (700)

Cp(660)

Chla bbp (700) bbp (l)

CDOM bbp (l) bbp (l)

Lus (l)

Oxygen profiles (WOA 2013)

Bio-Argo is growing : active / planed floats

• Australia 11 Southern and Indian Ocean

• Bulgaria 2 Black Sea

• Canada 24 Labrador Sea, Baffin bay (under ice)

• China 2 South China Sea

• France 70 Atlantic, Mediterranean Sea, Austral

• India 50 Arabian Sea, Austral (Indian) Ocean

• Italia 7 Mediterranean Sea

• Japan 3 Western Pacific

• Norway 2 Nordic Seas

• South-Africa 3 Austral Ocean

• UK 21 North Atlantic + Nordic Seas

• USA 90 Global (+ SOCOM)

Key numbers

Pre Bio-Argo era

• ~ 40,000 Chla fluorescence profiles over 1970-2012.

• un-calibrated profiles. • Scattered in various databases

Argo era

• More than 106 QC profiles. • 120,000 profiles per year

(>95% of the acquisition) • A single accessible database.

Next step from community planning: • Regional/basin scale experiments

• Closely integrated with data

assimilating models/state estimates

• Some (remote) biogeochemical hotspots (e.g. NA sub-polar gyre, southern Ocean) deserve to be observed at higher spatial & temporal resolution than others.

• Other can accommodate with a coarser network (e.g. large sub-tropical gyres area) .

• Core Argo strategy (1 float per square of 3° x 3° and profiling at a 10-day resolution) thus might be not adapted for Bio-Argo

• Additionally, cost issues make a global Bio-Argo network similar to Argo presently unrealistic.

Bio-Argo planning: Regional vs global

Bio-Argo planning: Regional vs global

• Rather than dispersing resources in a « scattered » Bio-Argo global array, the community prefer to target first regional hotspots (expecting a large return in term science for a restricted number of floats)

• These targeted areas have been identified/ chosen (not only by the Bio-Argo community but also by the biogeochemical community) because their are climate- change hotspots (take the pulse in key areas) and could be tackled in a more integrated way.

• Austral Ocean (SOCOM): CO2 drawdown, unexplored, experimental for coupled model-observation. US, South-Africa, Australia, India, France

• North Atlantic : AMOC and CO2 drawdown, major bloom of the global ocean: Euro-Argo, AtlantOs, US, Canada

• Mediterranean Sea => miniature Ocean with shorter time scale for the thermohaline circulation, societal aspects (very dense): Euro-Argo

• OMZ => interested countries (US, India, Germany, …) but not a really coordinated and sustained effort

Bio-Argo “HOTSPOTS”

BioArgo Global Biogeochemistry

Areas where 100 floats add significant constraints to

the Southern Ocean State Estimate

Fraction of Southern Ocean area where the error in monthly air sea flux

estimate exceeds 1 mol m-2 yr-1 as a function of the number of floats.

Observing System Simulation Experiments

Joe Majkut, Princeton Matt Mazloff, SIO

World Ocean Atlas 2013 Nitrate Stations 1998 - 2007

Winter

Summer

Spring

Fall

SOCOM 185 Floats All Seasons

Feb 24

Feb 20 Feb 25

Seasonal variation in Chla biomass (from OCR remote sensing) in the North Atlantic

North Atlantic sub polar gyre: The drivers of phytoplankton bloom - the uncertainties on CO2 sink

Bio-Argo pilot project: Mediterranean Sea deployment strategies within « bio-provinces »

Bio-Argo pilot projects: going forward

• From scattered individual projects to larger integrated and coordinated project =>

– OSSEs or bio-regionalization methods as a way to better refine sampling strategy and design a cost-effective system (e.g. not all sensors on all floats)

– Large pilot cooperative projects (e.g. SOCOM, North Atlantic) provide the critical mass to have resources for Bio-Argo data management that is effectively implemented

What would a global

biogeochemical array cost

per year?

50% (US?)

share per

year

Total cost

per year

Argo T/S array $10 Million $20 Million

Add O2 to Argo (Gruber et al.

2007; $7070/float)

$2.5 M

(350 floats/y)

$5 M

(700 floats/y)

Add Biooptics (sensor cost

1.75 x O2)

$4.4 M $8.8 M

Add Nitrate (sensor 3 x O2) $7.5 M $15 M

Add pH (1 x O2) $2.5 M $5 M

Total cost

Partner with Argo

$27 M

$17 M new

$54 M

$34 M new

These numbers are completely scaleable.