Subpolar Gyre Experiment in the North Pacific Ocean
Yutaka Michida1, Keisuke Mizuno2, Nobuyuki Shikama3 and Takatoshi Takizawa4
1 Hydrographic Department, Maritime Safety Agency
2 National Reseach Institute for Far Seas Fisheries, Fisheries Agency
3 Meteorological Research Institute, Meteorological Agency
4 Japan Marine Science and Technology Center
1 Background
Recently climate prediction models illustrate that the response of the ocean to the atmospheric change will be remarkably significant in the high latitude area of the North Pacific, as much as in the tropical oceans. In chemical aspects, it is suggested that the subpolar region of the North Pacific is one of the important candidate areas that absorb the anthropogenic carbon. In addition, cooling in winter resulting in strong vertical mixing there should play an essential role in forming the North Pacific intermediate waters and in sustaining the meridional circulation that may convey desolved materials such as carbon dioxide to the subtropics of the North pacific. Therefore the subpolar gyre in the North Pacific is one of the key areas to investigate the mechanisms of global change, an urgent international problem to be solved. In the area north of 40N in the Pacific, however, there have been very few oceanographic data available in comparison with other areas; the subtropical and the tropical Pacific, mainly because of extremely rough sea in winter.
In order to promote observational studies and developments of numerical models to simulate the circulation of the subpolar gyre, an inter-agency study group organized unofficially about 1 .5 years ago has been discussing about the research requirements and drafting the proposal for the Research Promotion Fund. And it has been concluded that we need to initiate a new research activity, Subpolar Gyre Experiment in the North Pacific Ocean', as an international cooperative study, basically for increasing observational facts and improving numerical models. It will also greatly contribute to WOCE, JGOFS or other international oceanographic programmes, by enhancing the observations in the area of data gap.
It is approved as a feasibility study in this fiscal year, and we have been asked to make sound and feasible implementation plan.
2 Discussion in the feasibility study
As the importance of the subpolar gyre in the North Pacific in the global climate system has been strongly recognized, researches on the circulation of it has been getting more active in these days. There have been proposed a significant hypothesis on the origin of NPIW and new knowledge on the changes of oceanographic condition related to climate change.
