Expressions of Intent for International Polar Year 2007-2008 Activities

Expression of Interest Details

PROPOSAL INFORMATION

Internal waves and mixing at and north of the semi-diurnal critical latitude  (Internal waves and mixing)

Outline
The kinetic energy available for oceanic mixing is extracted from large scales and, in a simplified view, funnelled through an energy cascade to smaller scales, ultimately leading to dissipation and mixing. Topography plays an important role in this energy transfer (e.g., by extracting energy from barotropic tides; enhanced diapycnal mixing over rough topography). The stress driven boundary mixing, generation of lee waves, reflection of internal waves from critical slopes, scattering of barotropic tide over rough topography, and deep solitons are some of the major mechanisms involved in ocean mixing. The mixing has large-scale consequences that influence the ocean circulation and has to be better understood and subsequently better represented in climate models. The proposed project aims to investigate mixing processes associated with internal wave-sloping boundary interaction with a focus at the critical latitude (and north) for semidiurnal (M2) frequency. Field observations from micro to mesoscale are planned at the continental slope near Bjørnøya and that west of Spitsbergen. Data will be contrasted to results from internal wave modelling. The field data set and the modelling activity will form the basis of a PhD study. The main scientific objectives are 1) to measure the internal wave climate near M2 critical latitude and at the Spitsbergen continental slope and contrast it to the Garrett-Munk deep-ocean internal-wave spectrum 2) to determine the critical latitude effects and establish a simple energy budget for mixing at the sites 3) to advance knowledge of mixing induced by breaking internal gravity waves 4) to apply and evaluate existing internal wave-wave interaction parameterizations for diapycnal mixing by measuring O(5m) vertical resolution shear (vertical derivative of horizontal current) and strain (vertical derivative of isopycnal displacement) profiles and dissipation profiles (by microstructure profilers) and finally 5) because the sites are on the path of the Atlantic Water (AW), to examine mean flow-internal wave interaction and the possible effects on extracting heat from the climatically important AW.

What significant advance(s) in relation to the IPY themes and targets can be anticipated from this project?
Existing internal wave-wave interaction parameterizations, often successful in the open-ocean, will be tested and (if necessary) improved for continental slope/shelf conditions. Such parameterizations might improve the representation of boundary mixing in large scale climate models. Furthermore a better understanding of the internal wave, topography interaction and critical latitude effects will be achieved.

What international collaboration is involved in this project?
1) Proudman Ocean. Lab. (POL): Bottom 1-m near bed turbulence and stress measurements (time series). 2) Uni.of Wales (UWB): high resolution ADCP measurements (within bottom 30-50m) (time series). 3) Scottish Assoc. for Marine Sci. (SAMS): time series of hydrography and microstructure profiles using HOMER. 4) Royal Netherlands Institute for Sea Research (NIOZ): time series from a fast response thermistor array and internal wave modelling

FIELD ACTIVITY DETAILS

Geographical location(s) for the proposed field activities:
Bjørnøya, 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 a lowered ADCP system).A McLane moored profiler (will measure time series of current and CTD profiles).Other instruments to be moored and deployed are available through own funding and international collaboration.Ship time can be usefully shared with other projects.

Will the project leave a legacy of infrastructure?
No.

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. Funding for the moored profiler will be sought through the Norwegian Research Council.

Has the project been "endorsed" at a national or international level?
The Norwegian IPY Committee will hold a meeting after the deadline of submission of this EoI. A copy will be sent to the Fridtjof Mehlum of the Norwegian Research Council (NRC).

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?
Yes

This is a free-standing activity. It will provide valuable information for the Polar Ocean Climate Processes (ProClim- funded by NRC) with focus at the same geographical areas.

How will the project be organised and managed?
Upon funding, the project will be managed at the Geophysical Institute, University of Bergen. Dr. Ilker Fer will lead the management, scientific coordination and field work. He will be largely advised by the Institute Director Prof. P.M. Haugan, who will be the responsible for the project on behalf of the Institute. Principal investigator from UK will be Prof. John M. Huthnance. Principal investigator from Netherlands 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 one PhD candidate. Students (undergraduate and/or graduate) will be encouraged to take part in the scientific cruise. Lectures are anticipated during the Svalbard summer school proposed separately and contributing to EC-DAMOCLES and IPY-CARE.

What are the initial plans of the project to address data management issues (as outlined in the Framework document?
Successful, conventional end products will be managed by respective natural marine data centres (NMD for NO; BODC for UK; NIOZ for NIOZ), and e.g. ICES. More complex data sets (turbulence measurements) will be made available upon publication upon request.

How is it proposed to fund the project?
Funding for the project will be sought through the Norwegian Research Council

Is there additional information you wish to provide?
This project is an intensive process study to be conducted during IPY. It is linked to long term monitoring past the IPY period by providing scientific understanding. So even if the project as such does not leave a legacy of infrastructure (2.4 above), it will contribute to increased value of monitoring.

PROPOSER DETAILS

Dr Ilker Fer
Bjerknes Centre for Climate Research & Geophysical Inst. UoB
Geophysical Institute, University of Bergen, Allegaten 70, Bergen
N-5007
Norway

Tel: +47 5558 2580
Mobile: no
Fax: +47 5558 9883
Email:

Other project members and their affiliation