Polar Ocean Climate Processes

2003-2006

Polar Climate Research Programme 2003-2006.
Project manager: Peter M. Haugan
The project will formally be closed in October 2007, but most of the research activity has ended.

In order to understand and predict large scale ocean climate variability, one needs to take into account a number of mesoscale and small scale processes controlling how properties (such as heat, salt, momentum, nutrients, tracers) are being transferred throughout the system. Three major regions can be distinguished in the geographical area of the Polar Climate Programme: the continental shelf, continental slope and deep basins. These are reflected in the first three work packages, WP1 - WP3. In deep basins, WP1, deep convection in regions of weak vertical stratification lead to the formation of deep and intermediate waters which are the main constituents of the Greenland-Iceland-Scotland overflows and ultimately of the North Atlantic deep water. The focus on shelves mainly concerns brine-enriched water, WP2, resulting from sea-ice formation in coastal polynyas and along topographically influenced fronts and ice edges. Interactions between shelves and deep basins are manifested in cross slope exchanges, WP3, involving slope convection and cascading.

Schematics of primary working areas for WP1 - WP3 are shown to the right. WP1 deals with the Greenland Sea, both the central gyre and the boundary region towards the Norwegian Sea. WP2 addresses both the Storfjord polynya and the ice edge area along banks in the western Barents Sea. WP3 addresses the corresponding cold outflows. WP3 mooring locations are indicated with open squares. WP4 addresses the entire area, and uses data and models for an even larger domain.

A crucial question is the relative importance and respective role of each of these processes. Paleoceanographers have claimed that deep ventilation alternates from a brine mode during ice ages to an open ocean convection mode during interglacial periods (Dokken and Jansen, 1999). Also active brine formation seems to be associated with rapid transitions between stadials and interstadials. Today both modes of deep ventilation coexist but are highly variable, and there even appears to be different modes within each category, particularly deep convection (Gascard et al., 2002).

Particularly WP2, but also the project as a whole, utilizes fjords as natural laboratories and takes advantage of the existing infrastructure in Svalbard.

In addition to the three topical work packages, efforts to synthesize and quantify the regional variability in each and the interaction between them, is organized in a fourth work package. There will be considerable collaboration between the work packages both logistically in relation to field work and concerning modeling. In particular the development of modeling tools, organized in WP2, will be useful to all the other WPs. It will be a unique achievement of the project to develop and test a fully coupled high resolution atmosphere-ice-ocean modeling system of the processes studied and apply it to observations from the region. High resolution radar satellite observations of sea ice have already been successfully used by the project manager and collaborators for polynya issues. Here such data will be combined with in situ observations and sophisticated models of atmospheric and oceanic boundary layers.

Key personnel and responsibilities:
Peter M. Haugan (Bjerknes): Project management and overall scientific responsibility.
Lars H. Smedsrud (Bjerknes): Project coordination activities.

Principal investigator Work Package 1: Tor Eldevik (NERSC)
Principal investigator Work Package 2: Peter M. Haugan (Bjerknes)
Principal investigator Work Package 3: Bjørn Ådlandsvik (IMR)
Principal investigator Work Package 4: Helge Drange (NERSC)

Recruitment:

Funded by ProClim:

• Post Doc positions (2 years):Ragnheid Skogseth at UNIS, Randi Ingvaldsen at IMR, and Jan Even Nilsen at NERSC
• Ph.D students Kari S. Berner at NP and Doroteaciro Iovino at NERSC

Funded by other:

• 1 Ph.D. student will work within the framework of a US-Norway collaboration project during 2003-2005 on topics relevant to work package 2.
• 2 graduate students at Geophysical Institute presently do thesis work very relevant to work packages 2 and 3.

External relations

ProClim will be coordinated with the Norwegian Ocean and Climate Project (NOClim) Phase II to be funded by KlimaProg for 2003-2006. This means in particular that the NOClim project office will assist ProClim with public outreach and links to broad international activities and programmes. ProClim will be viewed as a module in NOClim. The NOClim-ProClim links will be facilitated by having the same project manager and by the complementarity of the goals and activities. It is expected that the synthesis and production of assessment reports to the public and concerned ministries will be considerably strengthened by combining results from the two projects at the project and project office level.

References

Dokken, T. and Jansen, E. 1999. Rapid changes in the mode of deep and intermediate water formation linked with atmospheric and ice sheet variations during the last glacial. Nature 401, 458-461.

Gascard, J.-C., A. J. Watson, M. J. Messias, K. A. Olsson, T. Johannessen, and K. Simonsen, 2002: Long-lived vortices as a mode of deep ventilation in the Greenland Sea. Nature 416, 525-527.