Expressions of Intent for International Polar Year 2007-2008 Activities

Expression of Interest Details

PROPOSAL INFORMATION

Adélie Land Bottom water formation and Ice-Ocean interactioNs  (ALBION)

Outline
Several sverdrups of dense bottom water formation are believed to be produced within coastal polynyas around Antarctica (to be compared with about 1 Sv estimate for the Arctic). This production contributes a substantial part to the Antarctic Bottom Water (AABW). Originally believed to be a minor source of AABW, the Adélie Land Bottom Water (ALBW) is now recognized as the third source after the Weddell Sea Bottom Water WSBW and the Ross Sea Bottom Water (RSBW), providing as much as 25 % of the total AABW. By contrast to these two major sources which are formed by convergence and accumulation of brine-enriched shelf water over wide shelves, the ALBW is formed under strong katabatic winds in a wind-driven coastal polynya in the lee of the Mertz Glacier tongue. Persistent polynyas are exemplary sites of strong ice-ocean interaction. The Mertz Glacier Polynya (MGP) is the second in size of the East Antarctic polynyas. Dense water formed within the polynya accumulates in a depression (the Adélie Depression) located to the west of the polynya and ultimately spills into the deep ocean through a 200 m deep, 20 km wide channel. The densest part of the water column does not get through, providing a memory of winter processes across the summer season. Although summer cruises have provided a great deal of information on the important ice-ocean processes leading to dense water formation, a monitoring effort is necessary to complement these and to provide a better space-time coverage of the variability of this key region. In order to monitor the Adélie Land coastal zone area, we propose a threefold program : - a process study of the MGP area and of the Adélie Depression based on intensive synoptic CTD arrays with biochemistry, year round moored instruments and meteorological measurements taking benefit from available instrumentation from the french Dumont D'Urville base. - a long-term monitoring of the outflow of dense water at the outlet of the Adélie Depression from year round moored instruments. - an analysis of measurements collected at the ice edge by pelagic seals equipped with temperature and conductivity sensors. These measurements will be part of the NEOPP program designed at the study of the habitat of polar pelagic marine mammals. The animals represent unique platforms to explore under ice areas in all seasons including winter. The above observational program will be substantiated by analyses of remotely sensed data providing a large scale coverage of the sea ice (SAR, passive microwave, Cryosat altimetry) and hydrographic conditions (Altimetry, SST, ocean color) and by a modeling effort with a coupled ice-ocean model in order to document the important processes and extrapolate the discrete in-situ information to a more comprehensive time-space view of the area. In addition, the physical and biochemical observations will be used in the coastal ichthyology work performed in Terre Adélie (ICOTA project) and in the ecological study of Weddell seals feeding in the region (NEOPP). They will also be used as in situ validation means for animal borne measurements that feed the CORIOLIS/GODAE Center at IFREMER working as part of the ongoing operational oceanography effort. In short, this experimental work has important implication both for climatology and biodiversity of the Antarctic Ocean.

What significant advance(s) in relation to the IPY themes and targets can be anticipated from this project?
-Better understanding of sea ice-atmosphere-ocean interactions in persistent coastal polynyas with focus on the Mertz Glacier polynya -Monitoring of a key source region of Antarctic Bottom Water and estimate of dense water formation rate including variability -Validation of the use of animal-borne autonomous measurements for physical oceanographic purposes - Strengthening interdisciplinary work between physics, biogeochemistry and Antarctic predator feeding ecology in relation to sea ice variability

What international collaboration is involved in this project?
Australian and Japanese groups have done pioneering works in the region. They are natural partners.

FIELD ACTIVITY DETAILS

Geographical location(s) for the proposed field activities:
-Mertz Glacier Polynya (67°20S and 145°E) 2 lines of subsurface current moorings equipped with T/S sensors -Adélie Depression outflow: (66°S and 142°E) 2 lines of subsurface current moorings equipped with T/S sensors -Array of closely spaced CTD stations with biochemistry in summer

Approximate timeframe(s) for proposed field activities:
Arctic: n/a
Antarctic: 01/07 – 04/07:CM mooring deployments + CTD work (2 weeks)       01/08 – 04/08:CM mooring recovery and redeployment + CTD work (2 weeks)      01/08 – 04/08 : CM mooring recovery and redeployment + CTD work (2 weeks)

Significant facilities will be required for this project:
The MV Astrolabe from IFRTP would be the ideal platform for this work. Cruises could be coupled with those of the on-going national ICOTA Project lead by P. Koubbi.

Will the project leave a legacy of infrastructure?
Yes. We plan to maintain two moorings over 5 years.

How is it envisaged that the required logistic support will be secured?
Own national polar operator

Has the project been "endorsed" at a national or international level?
The present project is one of a few suggestions from the French Antarctic interdisciplinary community, especially between the ocean physics, sea mammal ecology and coastal ichthyology in the Adélie Land coastal region

PROJECT MANAGEMENT AND STRUCTURE

Is the project a short-term expansion (over the IPY 2007-2008 timeframe) of an existing plan, programme or initiative or is it a new autonomous proposal?
New

Although this is a new proposal, it benefits from several existing programmes in the same area, such as: "Temperature and salinity profile measurements in the Southern Ocean using southern elephant seals as oceanographic sampling platforms/ SEaOS" (since January 2004), see the IPY Expression of Intent "Novel Exploration of Oceans - Pole to Pole/NeOPP" by K. Kovacs; French programme ICOTA (Ichtyologie cotière en Terre Adélie) since 2000

How will the project be organised and managed?
-By June 2005: Submission of the final project to the International and National IPY Committees; -October 2005: Submission of the project to the national funding agencies (IPEV, CNES, INSU/CNRS); -February 2006: Ask for use of Astrolabe (IPEV, IFREMER). -2006: Preparation (CM moorings, ADCP and CTD) -Jan-April 2007: Field work (CM moorings + CTD station array) (2 weeks) -Jan-April 2008: Recovery and redeployment of CM moorings + CTD station array

What are the initial plans of the project for addressing the education, outreach and communication issues outlined in the Framework document?
-Preparation of a web site of the project -Special seminars for large public in the National Museum of Natural History -Contact to mass-media for publicizing the field work and its implication

What are the initial plans of the project to address data management issues (as outlined in the Framework document?
-Supply in near-real time raw data to numerical assimilation groups -Post-cruise calibration and validation of data -Submit the validated data in due time to one of the IPY designated data center

How is it proposed to fund the project?
After the evaluation of the scientific merit of the project by the International and National IPY Committees, the funding will be asked to national funding agencies (c.f. 3.2)

Is there additional information you wish to provide?
None

PROPOSER DETAILS

Dr Marie-Noelle HOUSSAIS
LODYC, Université Pierre et Marie Curie,
Tour 45-55, 4 place Jussieu
Paris Cedex 05
75252
France

Tel: 01 44 27 61 02
Mobile: no
Fax: 01 44 27 71 59
Email:

Other project members and their affiliation