The Ocean Circulation: the Last 50 years and the next 50 years. Is the end in sight?

Dr. Carl Wunsch
Massachusetts Institute of Technology

The first IAPSO meeting of the 21st Century and the end of the World Ocean Circulation Experiment (WOCE) provides an opportune moment to summarize how far we have come in the last 50 years, and makes it worthwhile to speculate a bit about where the field might be 50 years into the future. (A few people present will be able to see how it really comes out!)

The long development times of oceanic technologies and internal time scales relative to human planning and reward horizons tends to make progress look incremental. Furthermore, advances, once they are accepted, tend to become part of 'history' so rapidly that newcomers (graduate students) often lack an understanding of how great was the intellectual change involved or of the sometimes, huge effort required to bring about a capability that has become routine. In this talk I will try to assess the shift in understanding of the ocean circulation and its climate consequences over the past 50 years.

I will argue that despite the immense number of new questions and problems that have arisen from WOCE and related efforts, we are unlikely to see again another radical shift in view (primarily a consequence of the recently developed ability to observe all spatial scales of movement in the ocean.)

History teaches us that attempts to forecast the future directions of scientific fields are usually completely futile. (In 1950, no one perceived the impact the transistor would have on the whole of society, much less on the study of the ocean.) Nonetheless, physical oceanography at least, is a branch of fluid dynamics, and this field is one that has evolved greatly in the past 50 years. Some fields of science do mature, and become wholly incremental. I will speculate that in 50 years, barring some societal catasptrophe, that the physical oceanography of the general circulation will have become, under the impact of growing computing power, matured understanding of fluid flows generally, and ever more powerful observation technologies, a largely "solved" problem. There will be routine estimates of the three dimensional state, at very high resolution, over the entire water column made several times/day. Most of the remaining effort will be in boundaries of the field (biological and slow chemical reactions), and in trying to intepret very long forecast runs of coupled systems without an adequate data base.

Will we have biologically-based instrumentation? Quantum computation? Will the main activities of physical oceanographers be directed at the 'engineering' applications of biological productivity, weather and short-term climate forecasting, pollutant movement? Is this the definition of success?