Expressions of Intent for International Polar Year 2007-2008 Activities

Expression of Interest Details

PROPOSAL INFORMATION

CONVECTION. Resolving the modes of convection in the winter Greenland Sea  (Getting to grips with convection)

Outline
The aim is to solve the problem of how winter convection occurs in the Greenland Sea by an intensive study of chimney and other convection processes in the central part of the gyre in winter and summer, together with theoretical and modelling work. The experiment, which builds upon the international consortium deployed for the EU ESOP and CONVECTION projects, involves (a) an intensive CTD survey of the central gyre in winter-spring 2007; (b) identification of depth of convection, depth of Tmax layer, presence of chimney(s), and deployment of APEX floats in chimneys together with vertical profiling of carbon fluxes using laser imaging technology; (c) satellite-based analysis of ice conditions and application of salt flux model to determine role of ice production in overturning; (d) a return to the area in summer 2007 to map capping of chimneys by fresh water; (e) further cruises in winter and summer 2008 to map continuing development of the chimneys with further deployment of floats. The Tmax layer has been identified as a new (since 1990) feature of the Greenland Sea, deepening every year, which is a marker for the depth attained by convective processes. The laser system will be provided by LOV (Gorsky); it is self-contained and measures particle distributions from 60 microns to 5 cm between the surface and 3000 m. By lowering it through the centre of the chimneys (which are about 2500 m deep) the instrument measures the particle concentrations and fluxes.At the same time as the field work, an intensive theoretical and modelling analysis will be carried out of chimney structure and stability, to determine the reason for the extraordinarily long lifetime and stationarity of observed chimneys , and the possibility of vertical water transport within a chimney. Associated work (ASOF) on the variability of fresh water transport through Fram Strait will be used to assess the role of varying fresh water flux on convection, and this will also be modelled using a large-scale ice-ocean model developed by AWI.

What significant advance(s) in relation to the IPY themes and targets can be anticipated from this project?
The thermohaline circulation is a major driver of European climate and is strongly affected by fluxes from the Arctic Ocean. To understand its mechanism is to understand a vital component of the present polar environment (theme 1) together with the likelihood of serious change in coming years (theme 2). The linkages in Greenland Sea convection are with the Arctic Ocean outflow, the Arctic Oscillation and the N Atlantic inflow to the Arctic (theme 3).

What international collaboration is involved in this project?
Norway: involvement with field work by NPI and provision of ship. Germany: involvement in field and modelling work (AWI), provision of floats. France: carbon flux study using laser sampler. Denmark: remote sensing data provision.

FIELD ACTIVITY DETAILS

Geographical location(s) for the proposed field activities:
All to be done in central Greenland Sea gyre in vicinity of 75°N, 0°W.

Approximate timeframe(s) for proposed field activities:
Arctic: 03/07 – 04/07      08/07 –09/07      03/08 – 04/08
Antarctic: n/a

Significant facilities will be required for this project:
Small ice strengthened ship (e.g. “Lance” or “Jan Mayen”) for winter field work. Any oceanographic ship for summer field work. APEX floats for deployment. Ships can be used for other cruise work before and/or after work in gyre centre.

Will the project leave a legacy of infrastructure?
The floats launched into the chimney will last for up to 2 years. The data on central gyre structure, chimneys, and depth of Tmax layer will add to datasets collected since 1990, archived at ICES, Copenhagen.

How is it envisaged that the required logistic support will be secured?
Consortium
Another national polar operator
National agency
Own support
Other sources of support

Ships will be supplied by NPI for winter work.

Has the project been "endorsed" at a national or international level?
No

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

The project is new but is based on the work of CONVECTION and earlier EU and AOSB activities, and aims to completely resolve what is still an open question regarding the dominant mechanism and overall role of Greenland Sea convection.

How will the project be organised and managed?
The organisation will be the same as successfully achieved on CONVECTION, with the Co-ordinator and partners forming a steering committee to overview the scientific work, technical aspects and data management. Frequent meetings will be held, including pre- and post-cruise meetings.

What are the initial plans of the project for addressing the education, outreach and communication issues outlined in the Framework document?
There will be space aboard the ships for several graduate and undergraduate students from the participating institutions, with the possibility of an internet link for hands-on participation by home-based students and schools. Because of enormous popular interest in this topic, popular presentations will be made via the media.

What are the initial plans of the project to address data management issues (as outlined in the Framework document?
Data will be archived via ICES and issued in processed form together with all previous winter and summer data from the gyre centre as an “Atlas of Greenland Sea Convection” for use by all theoreticians and modellers.

How is it proposed to fund the project?
Funding will be sought from the EU, ESA and national funding agencies. Some in-house support will be available from NPI and AWI (especially ship time), while research student support will come from DAMTP.

Is there additional information you wish to provide?
None

PROPOSER DETAILS

Professor Peter Wadhams
Dept. of Applied Maths & Theoretical Physics
University of Cambridge
Wilberforce Road, Cambridge
CB3 0WA
UK

Tel: 44-1223-760370
Mobile: 44-0774-8032371
Fax: 44-1223-760493
Email:

Other project members and their affiliation