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NOClim I

Description

Norwegian Ocean and Climate Project (NOClim) Phase II.
Project manager: Peter M. Haugan

Summary
The project is a continuation of the NOClim Phase I project, but focussing all available KlimaProg resources on the fundamental and overarching issue of Atlantic Water flow towards and into the Nordic Seas. The project will be executed by combining theory and numerical modelling with analyses of recent instrumental data and reconstructions from proxy data. The project work will be organised in three modules:

Module A: Theory and modelling of meridional oceanic heat transport
Module B: Analysis of abrupt changes in the past
Module C: Analysis of modern variability and detection of significant changes

In addition, the project Polar Ocean Climate Processes (ProClim), funded separately by the Polar Climate Programme will be considered as a module D. The project intends to serve as an authoritative source of information and advice to the Research Council and the public concerning the difficult issues of possible rapid climate change related to ocean circulation. We will actively exploit international links and contacts both in scientific syntheses and public outreach, and also integrate other relevant national and international research results that emerge from other funding mechanisms, in particular the concurrent national Polar Climate Programme.

Objectives
The principal objective of the project is to significantly improve our understanding of processes which govern oceanic heat transport towards the Nordic Seas, and which provide the basis for atmospheric heat transport from the Atlantic sector towards northern Europe.
Subgoals:
1. To elucidate how stable the Atlantic Meridional Overturning Circulation (AMOC) is to human induced greenhouse warming.
2. To identify whether rapid climate transitions in the past were associated with changes in the overturning rate in the Nordic Seas.
3. To investigate whether the balance of evidence (from observations, process understanding and models) indicates that abrupt changes are underway or likely to happen in the near future.

The project descriptions for each of the three modules provide scientific discussion of the issues to be addressed, the background knowledge that exists, more detailed sub-goals, and references which are not repeated here. The present document contains an overview of what is planned to be done in the project and by whom, the total resources required, and linkages between activities. Near the end, there is also a discussion of the scientific context and chosen profile of the project. Further background is available on the web: http://www.gfi.uib.no/NOClimI, http://www.asof.npolar.no/ and http://www.nerc.ac.uk/funding/thematics/rcc/ .

Discussion of objectives

The main objective of module A is to examine the forcing, structure and sensitivity of the Atlantic Meridional Overturning Circulation in response to buoyancy forcing, internal mixing and wind driving, in idealized and realistic basin configurations

The main objective of module B is to unravel the chaining of events that occurred through known rapid changes in the MOC (Meridional Overturning Circulation).

The main objective of module C is to investigate how the oceanic fluxes of volume and heat into and out of the Nordic Seas relate to each other, and to the atmospheric and oceanic conditions within the North Atlantic and the Nordic Seas.

There is not a one-to-one correspondence between the stated sub-goals of the NOClim project as a whole (previous page) and these listed objectives. This is intentional. The main method in module A will be numerical modelling and theoretical interpretation. The main method in module B will be to obtain paleo proxy data and relate them to quantitative physical oceanography. The main method in module C will be comprehensive analysis of modern instrumental observations. The division in modules is a practical one, as the work within each module will be done by a group of scientists sharing data and tools in day-to-day work, while the contact between modules will mainly be on scientific interpretation and exchange. Each module can address the questions posed in their project description separately. However, the value of the research results and the principal objective of NOClim as a whole would be severely compromised if any one of the modules was not present.

In order to address subgoal 1, the modelling in module A will be essential. However, it is not only the most advanced modelling in A that will be used. Also combination with insights from B and C, and simplified, more theoretically oriented modelling in module A will be needed in order to put the conclusions on a firm basis and to understand the significance and various types of uncertainties in the results. Subgoal 2 is definitely most clearly related to module B, but modelling (A) and understanding of processes, time lags and responses as obtained from the modern data analysis (C) is also relevant. Subgoal 3 is an overarching goal for much of the work in C, but model related insights (A) will also be needed for an assessment of possible future changes, and precise characterization of previous events (B) is a necessary background for evaluating possible trends.

Overview of planned work in the modules
Module A will comprise efforts from
Principal Investigator Helge Drange (NERSC, and Geophysical Institute, UoB), Joe LaCasce and Arne Melsom (met.no), Ole Anders Nøst (NP), Tore Furevik and Peter M. Haugan (Bjerknes, and Geophysical Institute, UoB; at no cost)
The Ph.D. student is listed at NERSC but will also be affiliated with the Geophysical Institute.

Module B will comprise efforts from Principal Investigator Trond M. Dokken,
Svein Østerhus, Eystein Jansen, Carin Anderson Dahl, Mathias Moros, Helga Kleiven, Ulysses Ninnemann and one Ph.D student (Bjerknes), Nalan Koc (NP), I. Nick McCave, and Harry Elderfield, University of Cambridge.

Module C will comprise efforts from Principal Investigator Cecilie Mauritzen, and Arne Melsom (met.no), Øystein Skagseth, Martin W. Miles and Tore Furevik (Bjerknes), Harald Loeng and Kjell Arne Mork (IMR), Bogi Hansen (Faroese Fisheries Laboratory), Bill Turrell (Marine Lab, Scotland), Truls Johannessen, Kjell Arild Orvik (UoB)
Arne Melsom, Harald Loeng, Bogi Hansen, Bill Turrell, Truls Johannessen and Kjell Arild Orvik participate in this module at no charge for the project except travel.

Project management and the role of the project office

The project management structure and responsibilities will be as follows:

Project manager. Peter M. Haugan (funding equivalent to 20 % of full position)
Advisor: Jochem Marotzke (funding for travel and expenses)
Steering group: Helge Drange (NERSC), Ole Anders Nøst (NP), Trond Dokken and Svein Østerhus (Bjerknes), Cecilie Mauritzen (met.no), Harald Loeng (IMR) + ProClim repr.
Project office: Solfrid Sætre Hjøllo (30 % position to be funded)

Peter M. Haugan will serve as the project manager with overall responsibility for the scientific conduct of the project. This requires funding at the level of 20% of a full time scientist. He will actually use more time than this on in-kind research contributions, notably in module A and at no further cost. This funding of time spent by the project manager will be essential to secure that the duties in coordination, reporting to the research council as well as in various external connections, and contributions to overall synthesis, are properly carried out.

Jochem Marotzke is a key person behind the UK Rapid programme. From 2002, he serves on the NOClim Scientific Steering Group. He has visited Norway in 2001 and 2002 and is willing and interested to continue close contact with NOClim in a personal capacity as advisor to the entire project, as well as contributing directly to work in module A. Marotzke is a world leader in the field. We find his interest very inspiring and would like to continue to have him formally listed as affiliated with the project.

The proposed steering group comprises the module leaders and one deputy for each module, and also ensures representation from all participating institutions. We expect that very few if any formal decisions will have to be made at the level of the steering group. However, the steering group, chaired by the project manager and including the advisor, will be the highest level decision making body in the project. The Polar Ocean Climate Processes (ProClim) project funded by the Polar Climate Programme 2003-2006 (see below), will be viewed as a fourth module D in NOClim. ProClim can appoint two supplementary members of the NOClim Steering Group. They will be entitled to take part in Steering Group meetings as scientific representatives of their module D (just like the PI and deputy for each of modules A, B and C), but will not have a vote on NOClim-KlimaProg issues.

It was emphasized in the call for proposals that each of the modules should be possible to run independently of funding to the other modules. This has been built into the planning and organization of the present project. The day-to-day work will therefore proceed in each module with little interference across modules. The main task of the Steering Group is to advice and initiate cross-cutting activities and syntheses to maximise the outcome of the project as a whole with the help of the project office.

Experience from NOClim Phase I shows that it was crucial to maintain a well staffed project office to take care of internal and external coordination and public outreach (which got very good marks in the evaluation report). In particular, cross-task communication seemed to improve considerably with the emphasis on producing popular science articles with active involvement from a competent scientific coordinator. A continuation of this post at the level of 30 % of a full time scientist is a minimum for NOClim phase II. We welcome Solfrid S. Hjøllo back to this post when her parental leave period is finished.

Why do we need a well-staffed project office in the new project? Admittedly there will be smaller thematic spread within the project (definitely when considering only modules A, B and C) and fewer scientists involved so internal communication should proceed more smoothly. However, the experience gained will still apply. A competent scientific coordinator will act as a secretary to the steering group, and make sure that decisions are implemented and actions followed up. This scientific coordinator will also collate, make available, and integrate into the project relevant scientific results produced outside the project. Thereby and via public outreach activities, the project will serve as an authoritative source of information and advice to the research council and the public concerning issues of possible rapid climate change related to ocean circulation. The emphasis on synthesis will be much greater in Phase II than in Phase I. Particularly the need to integrate information and research results from a wide range of sources outside the modules will require substantial efforts at the level of a qualified scientist. This work produces results which are not always publishable in the scientific literature and therefore not suitable targets for scientists in the modules, but still very important for the project as a whole and its deliverables with respect to the expectations.

Budgeted costs for joint project meetings include costs of facilities, invited guests and travel for active contributors to modules A, B, and C. Scientists from associated projects, e.g. module D, may participate but have to cover their own travel costs. The scientific advisor will visit Norway at least once per year, including some extended stays. Running expenses for public outreach will be kept very low, emphasizing use of web site and contributions from the project office and project scientists to periodicals and television, but including a hard copy brochure in the final year of the project. There will also be some travel to present the project particularly in important international contexts.

Recruitment
We ask for funding of one Ph.D. student in module A. In module B, the KlimaProg funding is required for senior scientist contributions and running expenses, but the Bjerknes Centre/University of Bergen guarantees funding of a Ph.D. student to work within the module. Module C includes scientists with relatively recent PhD and still in a recruitment phase. We will therefore have recruitment of young scientists in each of the three modules. This ratio between funding for recruitment vs. funding for scientists and running expenses, is the maximum we can justify scientifically in order to put together a project which can fulfil the expectations. The coordination activities are not suitable for recruitment positions. Other Ph.D. students funded via other mechanisms will benefit from the project and contribute indirectly although their Ph.D. studies are not entirely in phase with the project. 2-3 of the Ph.D. students already funded and presently supervised by the project manager can be associated with the project, benefit from it and provide results to be integrated in the project. There will be others via other mechanisms, notably EU and Polar Climate projects to be linked to NOClim activities. Therefore, we feel that the intention from KlimaProg to ensure recruitment within each project will be more than fulfilled by NOClim.

Relations to other projects and activities
Maintenance of linkages to international programmes and integration of external information will be done in all modules, but will be primary tasks of the project manager and project office. The specific modules and tasks of NOClim Phase II have been chosen to make original and significant contributions to the wider questions discussed in the mentioned programmes, and to build national competence in crucial research fields where competence is presently too weak.

The project entitled Polar Ocean Climate Processes (ProClim) funded by the Polar Climate programme 2003-2006, will be viewed as module D in NOClim. The NOClim-ProClim links will be facilitated by having the same project manager and by the complementarity of the goals and activities. As described above, ProClim can appoint two supplementary members of the NOClim Steering Group, while the project manager acts as chair of the steering group. 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.

The funding limitations imposed on NOClim Phase II compared to earlier projections and expectations when NOClim Phase I and the UK Rapid programme started, have led to considerable fousing of the project compared to the previous phase. While Phase I was a wide collaboration among many groups over many topics and included field data collection in process studies and for monitoring in many locations, Phase II in modules A, B and C deals exclusively with the crucial issue of ocean heat transport towards our region. The project will fund the collection of field data only for a single specialized paleo study, but mainly deals with data analysis and modelling. There is a smaller group of scientists directly involved and much less disparity in issues addressed.

In NOClim phase I, there were 7 tasks each with a task leader, and each task had contributors from several Norwegian institutions. A separate Scientific Steering Group (SSG) was set up, including 4 senior scientists who were not task leaders. This SSG was a very useful entity to oversee the complex linkages between tasks as well as externally. Particularly in the beginning of NOClim Phase I, there was considerable information exchange with RegClim in order to ensure that individual scientists were informed of activities, expertise and (model) data sets. Contacts with the UK Rapid programme was initially via the SSG and project manager, but was later expanded to mutual personal contacts at the level of individual scientists. RegClim has been represented on the SSG from the start, and Jochem Marotzke, a key person in UK Rapid programme, was a member of the NOClim SSG during 2002.
Information exchange with RegClim will still be relevant, but there is agreement among NOClim and RegClim that there is no longer a need for formal cross-representation in the steering groups. There may also be other new projects within the Polar Climate funding mechanism with similar relevance to NOClim. In order to keep the project management efficient, the steering group will be limited to the personnel mentioned above. General information exchange with other projects will take place by other means as appropriate.

The scientific context and profile of the project
The more lengthy project description that was allowed when the NOClim Phase I proposal was submitted includes a still relevant background discussion. NOClim Phase II, as its predecessor NOClim Phase I, will be strongly linked to international initiatives, notably the Arctic and Subarctic Ocean Flux Study and the Rapid programme. These two programmes have a broader scope and much larger resources than NOClim. Activities coordinated through the CLIVAR Atlantic Implementation Panel and several ongoing EU projects, provide additional context for the Norwegian contribution to international research via the present project. These other activities will also provide research results to be assimilated in syntheses and public outreach activities within NOClim.

Why focus on the oceanic part of the heat transport?
In order to efficiently address critical questions for our climate with the limited resources available, this project will focus on processes directly and immediately associated with the oceanic heat transport in the Atlantic and Nordic Seas. The northward heat transport of the Atlantic Ocean is largest in the tropics and is gradually reduced northwards. In climatologies, the ocean heat transport is normally deduced as the residual from the total energy budget taking into account atmospheric transports estimated from data and models. Oceanographic data collected during the WOCE period allowed the first reliable direct estimates of ocean heat transport in the global oceans (Bryden and Imawaki, 2001), but with extremely poor temporal and spatial resolution also in the North Atlantic. The mean net advective oceanic heat transport into the Nordic Seas and the Arctic is in fact better known since the semi-enclosed character of the area allows the use of budget methods from relatively limited data (Simonsen and Haugan, 1996).

In a pioneering study of North Atlantic climate, Bjerknes (1964) argued that short term variability in Sea Surface Temperature (SST) is governed primarily by the atmosphere, while longer-term variability is governed by oceanic processes. This notion has been followed up by a large number of investigators (e.g. Deser & Blackmon, 1993, Kushnir, 1994, Hansen & Bezdek, 1996, Sutton & Allen, 1997, Marotzke & Pierce, 1997, Nilsson, 2000). For climate variability on a range of time scales, improved understanding of the coupling processes and various teleconnections, such as between ENSO and the North Atlantic, are of interest. The present project does not attempt to cover all these possibilities, some of which are better studied by other existing and strong research groups. Rather we build upon regional strengths which we may have in the Norwegian community, and focus on key processes which have been suggested as candidates for rapid climate changes. These processes are mainly oceanic.

In a very recent publication, Seager et al. (2002) by analysis of a 50 year NCEP data set, find that the warm wintertime surface air temperature anomaly in western Europe is primarily caused by zonal advection of warm air from the open sea and only weakly affected by oceanic heat flux divergence. The atmospheric wind pattern, and particularly the Icelandic Low, is forced thermally and by the net orographic forcing of the Rocky Mountains, i.e. by atmospheric processes which are reasonably well understood. Seager et al. (2002) conclude that "The deviations from zonal symmetry of winter temperature in the Northern Hemisphere is fundamentally caused by the atmospheric circulation interacting with a mixed layer ocean". In the principal objective of the project we focus on "processes which govern oceanic heat transport towards the Nordic Seas, and which provide the basis for atmospheric heat transport from the Atlantic sector towards northern Europe". The study of Seager et al. would agree that oceanic heat transport into the Nordic Seas is important regionally, since they find that the oceanic heat flux divergence in the Norwegian and Barents Sea determines ice extent, and that a very dramatic cooling would occur if this northernmost extension of the oceanic heat transport was reduced.

However, with this important exception, the findings of Seager et al. (2002) seem to imply that the role of the Gulf Stream and the North Atlantic Drift for the climate of Europe is minor, and that the North Atlantic may be approximated as a mixed layer storing heat from summer to winter and having no dynamics. Clearly this conclusion does not carry over to situations where extended ice cover would be possible (such as in past glaciations), since the seasonal heat storage in the ocean would then practically cease and could not sustain a winter time heat loss. However, Seager et al. (2002) have contributed an important demonstration of the role of open water masses in reducing seasonality and providing a maritime climate downstream of the atmospheric flow pattern, whereas a continental climate with cold winters prevails along coasts with predominantly offshore winds. These effects are the main reasons for the east-west asymmetry in winter air temperature across the northern Atlantic in contrast to some popular notions about a more direct role of the Gulf Stream, notions which even have found their way into scientific circles.

The findings of Seager et al. that the oceanic heat transport warms winters over land in an almost zonally uniform way does not however rule out a possible role of ocean circulation in rapid climate change. The oceanic heat transport provides the source for a significant warming of the atmosphere at high latitudes (6 ºC north of 35 ºN in the Atlantic in their estimates, but rather uncertain). That this contribution to winter time warming of the air is more zonally uniform than hitherto assumed does not remove its effect on climate. One rationale for a primary focus on oceanic processes in this project, is that the mentioned atmospheric processes are comparatively well understood, whereas the dynamics of the ocean circulation is poorly understood. The atmosphere is not neglected in the project. Atmospheric data are considered, and some coupled AOGCM studies are included, but the focus is kept on the oceanic part for which so little is firmly known, and such a wide range of hypotheses exists.

References
Bjerknes, J. 1964. Atlantic Air-Sea Interaction, Adv. Geophys. 10, 1-82.
Bryden, H.L. and S. Imawaki 2001. Ocean Heat Transport, p. 455-474 in Siedler, G., J. Church & J. Gould (Ed.): Ocean Circulation and Climate. Observing and Modelling the Global Ocean. Volume 77 in the International Geophysics Series. Academic Press, San Diego, 712 pp.
Deser, C. and Blackmon, M.L. 1993. Surface climate variations over the North-Atlantic Ocean during winters - 1900-1989 . J. Clim. 6, 1743-1753.
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.
Hansen, D. V. & H. F. Bezdek 1996. On the nature of decadal anomalies in North Atlantic Sea Surface Temperature, J. Geophys. Res., 101, 8749-8758.
Kushnir, Y. 1994. Interdecadal variations in North Atlantic sea surface temperature and associated atmospheric conditions, J. Climate, 7, 142-157.
Kushnir, Y and Held, IM , 1996. Equilibrium atmospheric response to North Atlantic SST anomalies. J. Clim. 6, 1208-1220.
Marotzke, J. and W.P. Pierce 1997. On spatial scales and lifetimes of SST anomalies beneath a diffusive atmosphere. J. Phys. Oceanogr. 27, 133-139.
Nilsson, J. 2000. Propagation, Diffusion, and Decay of SST Anomalies beneath an Advective Atmosphere. J. Phys. Oceanogr. 30, 1505-1513.
Seager, R., D.S. Battisti, J. Yin, N. Gordon, N. Naik, A.C. Clement and M.A. Cane 2002. Is the Gulf Stream responsible for Europe's mild winters? Q. J. R. Meteorolo. Soc. 129, 1-xx.
Simonsen, K. & Haugan, P. M. 1996. Heat budgets of the Arctic Mediterranean and sea surface heat flux parameterizations for the Nordic Seas, J. geophys. res. 101(C3), 6553-6576.
Sutton, R. T. & M. R. Allen 1997. Decadal variability in North Atlantic sea-surface temperature and climate, Nature, 388, 563-567.