The Southern Ocean Observing System SOOS

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The Southern Ocean Observing System (SOOS)
With additional support from
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Talk Outline

• Why are coherent, sustained observations of the
  Southern Ocean needed?
• Who would use them?
• What aspects of the Southern Ocean would a
  monitoring system address, and how?
• What is already in place, and what are the gaps?
• Where are we in relation to planning and
  implementing the observing system, and what is
  next?
• How would a SOOS link to other international
  efforts?

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Talk Outline

• Why are coherent, sustained observations of the
  Southern Ocean needed?
• Who would use them?
• What aspects of the Southern Ocean would a
  monitoring system address, and how?
• What is already in place, and what are the gaps?
• Where are we in relation to planning and
  implementing the observing system, and what is
  next?
• How would a SOOS link to other international
  efforts?

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Global reach of the Southern Ocean
Lumpkin and Speer (2006)
Critical part of the global thermohaline
circulation
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Change in zonally-integrated ocean heat content
since 1955 is largest in the southern oceans
Levitus et al., 2005
Important term in global heat budget, but
Southern Ocean is still undersampled compared
with rest of World Ocean
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Boening et al., 2008
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Warming in ACC, no change in overturning?
Comparison of Argo CTD data along streamlines
shows warming across the Southern Ocean,
strongest on southern flank of ACC. Southward
shift of isopycnals BUT little change in tilt,
hence no change in upwelling (unlike in IPCC
models).
Boening et al., 2008
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Freshening of AABW
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The Weddell gyre circulation and the area of
observations carried out during WECCON and CASO
Fahrbach, AWI
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Area of WSBW on the transect decreased by
25 from 1992 to 2008
1992
2008
Fahrbach, AWI
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Bottom melting heat source and effect of
pressure.

• Mode 1 Thermohaline circulation induced by sea
  ice formation and drainage of dense saline water.
  Melting point decreases as much as 1oC due to
  0.00075 oC/dbar-1
• Mode 2 Direct inflow of intermediate-depth
  warm water from the slope-front region (e.g.
  Circumpolar Deep Water intrusion through deep
  troughs).
• Mode 3 Ice-front interactions (tidal pumping,
  coastal currents)

AASW
CDW
ISW
Jacobs et al., 1992

• Ice shelf water may refreeze to form marine ice,
  or sink to participate in the formation of
  Antarctic bottom water, which regulates global
  climate.
• Mode 1 dominates for large ice shelves in the
  Weddell, and Ross seas.
• Mode 2 melts large volumes of ice where deep
  water has access to glacier grounding lines, e.g.
  Amundsen Sea.

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Conclusions

• Ice shelf melting controls gt 50 of the ice
  sheet/ice shelf mass balance.
• This neglects ice-front sub-aqueous melting.
• Low melt on large ice shelves (far from CDW),
  Queen Maud Land, East Peninsula.
• High melt on West Peninsula (CDW), Amundsen,
  Bellingshausen sea (CDW), Wilkes Land (?).
• Quadratic dependence on temperature where CDW
  fuels high melt.
• Elsewhere, linear relationship might still hold
  but not enough ocean temperature data near GL.

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Ocean uptake of carbon dioxide
Sabine et al., 2004
Southern Ocean a key region for uptake of
anthropogenic CO2 but is the carbon sink
weakening (Le Quéré etc)?
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Le Quere et al., 2007
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Why a SOOS (continued) ?

• Krill stocks in key parts of the Southern Ocean
  are in steep decline need to understand why, and
  the implications.

(Atkinson et al., Nature, 2004)
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Why a SOOS (continued) ?

• Changes in Southern Ocean temperature and
  circulation could have strong impacts on West
  Antarctic ice sheet (and hence global sea level)
• Nutrients exported from the Southern Ocean
  support 75 of oceanic primary production north
  of 30S (Sarmiento et al.)
• The Southern Ocean includes some of the most
  productive and unique marine ecosystems on Earth
• etc

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Why do we care if SO changes?

• Potential for positive feedbacks influencing
  global climate
• Sea ice albedo
• Carbon uptake
• Thermohaline circulation
• Sea-level rise
• Impact of acidification on ecosystems
• Impact of climate change on ecosystems (warming,
  freshening, ?mixed layer, ?light, ?circulation,
  ?sea ice, ?winds)

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Talk Outline

• Why are coherent, sustained observations of the
  Southern Ocean needed?
• Who would use them?
• What aspects of the Southern Ocean would a
  monitoring system address, and how?
• What is already in place, and what are the gaps?
• Where are we in relation to planning and
  implementing the observing system, and what is
  next?
• How would a SOOS link to other international
  efforts?

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Potential users of a SOOS include

• Research community
• Resource managers (including CCAMLR etc)
• Policy makers (when is it time to act? What are
  the consequences of not acting?)
• IPCC
• Local planners (sea-level rise)
• Antarctic tourism
• Shipping operations
• Weather and climate forecasters
• Education
• Etc.

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Talk Outline

• Why are coherent, sustained observations of the
  Southern Ocean needed?
• Who would use them?
• What aspects of the Southern Ocean would a
  monitoring system address, and how?
• What is already in place, and what are the gaps?
• Where are we in relation to planning and
  implementing the observing system, and what is
  next?
• How would a SOOS link to other international
  efforts?

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Scope of the SOOS

• Space
• circumpolar
• Subtropical Front to coast / ice shelf grounding
  line
• Time
• days to decades (longer-term proxies from ice and
  sediment cores are critical, but lie outside of
  SOOS)
• Domain
• sea surface to sea floor (including bathymetry)
• ocean sea ice
• include air-sea flux, not upper atmosphere
• include sub-ice shelf cavity, not glacial ice
  itself
• Feasibility/readiness
• consider READY NOW, 5-10 YEAR VISION and BY 2030
• consider both MINIMAL and IDEAL

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Scope of the SOOS

• Discipline
• physics (ocean circulation and sea ice)
• biology and ecology (microbes to whales...)
• biogeochemistry
• bathymetry
• surface meteorology
• Models Emphasis is on sustained observations,
  but modelling plays a key role in
• system design
• interpolation and interpretation of sparse
  observations
• demonstrating utility of SOOS (eg initialisation
  of climate models)

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Talk Outline

• Why are coherent, sustained observations of the
  Southern Ocean needed?
• Who would use them?
• What aspects of the Southern Ocean would a
  monitoring system address, and how?
• What is already in place, and what are the gaps?
• Where are we in relation to planning and
  implementing the observing system, and what is
  next?
• How would a SOOS link to other international
  efforts?

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Some examples of observing system elements
already in place
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Hydrography CTD/XBT/CO2 5-10 yr interval
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Argo
http//argo.ocean.fsu.edu/
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Sound sources deployed in Weddell Sea to track
modified Argo floats under ice
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Temperature and current field in the area of Maud
Rise derived from floats Olaf Klatt
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Tagging of marine mammals (SEaOS etc)
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Elephant seal oceanography
Mapping the ocean underneath the sea ice for the
first time (Charassin et al., PNAS, 2008).
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SEaOS Number of profiles
SODB 10513 Argo 19463 SEaOS 22230
Courtesy L. Boehme
http//biology.st-andrews.ac.uk/seaos/index.html
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Mapping high latitude fronts
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Sea ice formation from salinity change
Charassin et al., PNAS, 2008
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Near circumpolar coverage from elephant seal data

Other species can be targeted to access specific
icy regions. Invaluable data for both ecological
and physical sciences.
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Continuous Plankton Recorder Tows 1991-2008
The Survey coversgt70 of the Southern
Ocean October to April
Approximately40-50 tows each year gt4,000 samples
p.a. 5 n-mile resolution
135,000 nauticalmiles of data havebeen
collected since 1991
This represents morethan 27,000 samples, 200
taxa environmental data
Australia, Japan, NZ, Germany, UK, USA, Russia
Hosie et al
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• Above plus-
• Satellites (e.g. SeaWiFS, Cryosat)
• Current meter arrays
• Tide gauge network
• Sediment trap moorings
• Underway measurements (e.g. CO2 , Salinity)
• Sea ice thickness snow cover drift
• Etc.

What observing system elements are already in
place?
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Gaps in the observing system in the Southern
Ocean region

• Ice-covered regions still poorly sampled, despite
  progress
• Deep ocean below depth of Argo
• Ocean in ice shelf cavities
• Seabed is poorly observed (benthic communities
  etc)
• Non-physical measurements rarely routinely made
  (need other sensors for Argo etc)
• etc

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Gaps in the observing system in the Southern
Ocean region

• Routine measurements beneath the ice shelves
  required to understand how the ocean/ice-shelf
  interaction will change as the climate alters,
  and what the impacts may be for deep and bottom
  water formation and the global overturning in the
  ocean
• Development of new sensors and methodologies is
  key (e.g. biogeochemistry sensors to Argo floats,
  automated under-ice measuring systems, technology
  to study the long-term impact of seasonal ice
  cover on pelagic and benthic communities)

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Gaps in the observing system in the Southern
Ocean region

• Need to sample the polar oceans routinely and
  cost-effectively with an appropriate level of
  coverage to capture the main oceanographic,
  meteorological, cryospheric and ecosystems
  processes taking place there that contribute to
  global change

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Talk Outline

• Why are coherent, sustained observations of the
  Southern Ocean needed?
• Who would use them?
• What aspects of the Southern Ocean would a
  monitoring system address, and how?
• What is already in place, and what are the gaps?
• Where are we in relation to planning and
  implementing the observing system, and what is
  next?
• How would a SOOS link to other international
  efforts?

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SOOS Timeline

• August 2006 Initial scoping workshop, Hobart
• October 2007 Workshop in Bremen. Planning and
  writing tasks assigned
• July 2008 St. Petersburg progress review meeting
• January 2009 Make draft SOOS planning document
  available to community for comment
• February 2009 Comments received
• March 2009 Publish report
• April 2009 Commence implementation...

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SOOS Structure

• SOOS planning document (to go out to the
  community for comment) will outline the aspects
  discussed here-
• why sustained observations are needed in the
  Southern Ocean and what science/policy questions
  they address,
• what mix of observations are required to address
  these questions,
• what is presently done and what is possible,
• a vision for the future (in 5-10 years and by
  2030)

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SOOS designed to address six key challenges

• Role of Southern Ocean in global freshwater
  balance
• Stability of Southern Ocean overturning
• Stability of Antarctic ice sheet and future
  contribution to sea-level rise
• Future of Southern Ocean carbon uptake
• Future of Antarctic sea ice
• Impacts of climate change on Antarctic ecosystems

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(draft)
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(draft)
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Strawman Southern Ocean Observing System

• Initial SOOS consists of coordination/enhancement
  of extant elements, as discussed, including-
• Repeat full-depth hydro/tracer sections along
  WOCE lines
• Profiling floats, open ocean and under sea ice
• Sensors on marine mammals
• Sea ice observations
• Ocean-ice shelf interaction
• Surface meteorology observations
• Surface and sea-ice drifters
• Ecological monitoring

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CFC-11
Orsi et al., 1999
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Strawman Southern Ocean Observing System

• 5-10 years and 2030 vision (see planning
  document for details) as previous, but including
• Enhanced profiling floats with additional
  sensors, depth range and longevity.
• Cost-effective time series stations, using data
  capsule technology and expendable moorings.
• Supply/research ships doing routine
  surveys/sections on way into Antarctic bases
• Network of integrated fast ice mass balance
  stations
• A network of ice-capable gliders
• etc

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Strawman Southern Ocean Observing System

• SOOS coordination group to oversee the
  implementation of the observing system, plus-
• Relevant data archaeology
• Delivery of Southern Ocean climate information
• Modeling
• Identification of remote sensing needs
• Identification of key gaps requiring enhanced
  process understanding
• Array design studies
• Technology development requirements

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Strawman Southern Ocean Observing System

• As an example recommended repeat hydrography,
  with countries committed or interested in
  occupying the lines.

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Talk Outline

• Why are coherent, sustained observations of the
  Southern Ocean needed?
• Who would use them?
• What aspects of the Southern Ocean would a
  monitoring system address, and how?
• What is already in place, and what are the gaps?
• Where are we in relation to planning and
  implementing the observing system, and what is
  next?
• How would a SOOS link to other international
  efforts?

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SOOS Implementation

• Buy-in of international programmes of relevance
  to SOOS (SCAR, SCOR, GOOS, CAML, POGO,
  WCRP,JCOMM, GCOS...), leading environmental
  agencies and other key players.
• Links between SOOS, research programmes and
  international organisations will be effected by
  the SOOS coordination group.
• Group will also oversee coordination of field
  activities development of a funding strategy
  etc.

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SOOS and POGO

• POGO was one of the initial supporters and
  sponsors of SOOS continuing endorsement is
  needed.
• POGO community can help by circulating details of
  the planning document and sending feedback to
  Steve Rintoul (Steve.Rintoul_at_csiro.au) and/or
  Mike Sparrow (mds68_at_cam.ac.uk)
• To be successful, SOOS will need all nations with
  current active interests in the Southern Ocean to
  participate, and to draw new nations in POGO
  can stimulate this.

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More information
(www.clivar.org/organization/southern/expertgroup/
SOOS.htm)
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A final word
Many more voyages of discovery are also needed,
especially in the vast expanses of the southern
seas that remain relatively unexplored Trouble
d Waters The Economist, Jan 3rd 2009