Expressions of Intent for International Polar Year 2007-2008 Activities

Expression of Interest Details

PROPOSAL INFORMATION

Dense water cascade on slopes: mixing and fate  (Cascading and mixing)

Outline
Dense water masses formed on the Arctic and Antarctic shelves and their gravity-assisted downflow off continental shelves (termed “cascading”) is crucial for the present climate and the global-scale ocean circulation. Mixing associated with cascading causes irreversible modifications in the water mass properties. Cascading is important for carbon fluxes, nutrient fluxes and shelf-deep water exchange. Measuring, parameterizing and modelling mixing have received much attention in the scientific literature, but still remain unsatisfactory. In the proposed activity we focus on the Arctic: in particular the dense water cascade from Storfjorden, its evolution and mixing. Besides being an effective dense water “factory” (produces 5-10% of circum-Arctic brines), Storfjorden overflow is well-documented, occurs regularly, and the site is logistically favourable and easily accessible. The activity will be based on field measurements and modelling efforts with an aim to estimate evolution and mixing of shelf-origin dense water, and its general contribution to the large scale ocean circulation. The specific objectives are 1) measure and model details of the cascade, turbulence and mixing 2) validate shelf-and-slope models’ representation of dense shelf-water formation, overflow, turbulence and mixing on the continental slope; 3) evaluate the sensitivity to both ambient and initial conditions; 4) apply validated models to infer fluxes in areas with scarce observations; 5) hence estimate cascading fluxes and their contribution to oceanic water masses.

What significant advance(s) in relation to the IPY themes and targets can be anticipated from this project?
The initiative is a process-study with purely natural science research focus. The deliverables are a data set to test models’ skill to represent cascade and mixing; a better understanding of entrainment and mixing, sensitivity to initial and ambient conditions; flux estimates in representative identified locations which overall will lead to a more accurate estimate of contribution to the large scale circulation. By addressing the above, our understanding of the link between dense water production, cascades, ventilation of polar regions and the rest of the globe will be advanced.

What international collaboration is involved in this project?
1) University of Bergen: field work including cruise mobilization, technical support, calibrations; continuing ADCP for inter-annual variability; analysis (Thorpe scales from CTD data; historical data for seasonal variations and context) 2) Netherlands Institute for Sea Research (NIOZ): cruise participation and analysis of fast-sampling thermistor string for turbulence and mixing. q2_1_Location : Svalbard, Western Barents Sea

FIELD ACTIVITY DETAILS

Geographical location(s) for the proposed field activities:
Svalbard, Western Barents Sea

Approximate timeframe(s) for proposed field activities:
Arctic: 06/07 – 08/07 (1 month in total)            
Antarctic: n/a

Significant facilities will be required for this project:
Surface ship (conventional with lowered ADCP). Instruments to be moored and deployed otherwise are available through own funding and international collaboration. Ship time can be usefully shared with other projects. SAMS is a partner in Marine Laboratories, Svalbard; SAMS’ separate EoI requires relevant sea bed observatories, AUV and ROV.

Will the project leave a legacy of infrastructure?
An invaluable data set will be used to test/improve predictive models. The end products are the data set and the model.

How is it envisaged that the required logistic support will be secured?
National agency
Own support
Other sources of support

Valuable instrumentation is available by own funding and international collaboration. Time frame for the field work is typical of the scientific cruises that the Geophysical Inst. Uni. of Bergen (UoB) routinely requests to the site and allows time to bid for a UK ship.

Has the project been "endorsed" at a national or international level?
It is under consideration by the UK IPY Committee. It is an extension of the existing POL 2001-06 science programme, approved and funded by NERC UK, reviewed and endorsed by the 2004 Science and Management Audit of POL, and will be reviewed in 2006.

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

This is free-standing. It will benefit from the planned AOSB-CliC and EC-DAMOCLES mooring at the Storfjorden sill and existing time series (Norwegian ProClim). It will complement ProClim and present UK-RAPID project “Processes controlling dense water formation and transport on Arctic continental shelves”. It extends existing 2001-06 POL cascading studies.

How will the project be organised and managed?
Upon funding, the project will be managed for the UK by the PI. Prof. John Huthnance at the Proudman Oceanographic Laboratory, including acting as Principal Scientist for any UK ship provision. This will be in close liaison with the Geophysical Institute, University of Bergen, where Dr. Ilker Fer will lead the management, scientific coordination and field work. The Netherlands PI will be Dr. Hans van Haren.

What are the initial plans of the project for addressing the education, outreach and communication issues outlined in the Framework document?
The project will recruit a PhD candidate. We expect at least two students from UK & NO participating in the scientific cruise. Lectures are anticipated in EU programmes. Students, enrolled at a University, will benefit from UK supervision guidelines.

What are the initial plans of the project to address data management issues (as outlined in the Framework document?
Conventional products will be managed by respective national marine data centres (BODC, NMD, DMG/NIOZ) with usual forwarding to ICES. More complex data sets will be available upon publication. Under UK Environmental Data Regulations BODC will manage and make available all UK data after a period for analysis.

How is it proposed to fund the project?
Funding for the project will be sought in the UK through NERC Core-Strategic and responsive mode proposals and in Norway through the Norwegian Research Council.

Is there additional information you wish to provide?
This process-oriented study has timely collaboration of modelling and observations between UK and NO. A similar EoI is to be considered by the national committee of Norway.

PROPOSER DETAILS

Pro John Huthnance
Proudman Oceanographic Laboratory (POL)
Joseph Proudman Building, 6 Brownlow Street,
Liverpool
L3 5DA
UK

Tel: +44 151 795 4852
Mobile: no
Fax: +44 151 795 4801
Email:

Other project members and their affiliation