William R. Young

Scripps Institution of Oceanography, University of California, San Diego

The National Science Foundation (NSF) tasked the U.S. physical oceanographic community in 1997 to evaluate the current status of research in physical oceanography and to identify future opportunities and infrastructure needs. A workshop was held in Monterey, California from December 15-17, 1997 and was attended by 46 scientists representing the community of NSF-supported investigators. A subtheme of the meeting was the role and effectiveness of the NSF's core program in physical oceanography. Input via electronic mail from the wider scientific community was sought both before and after the meeting.

The community was asked to consider advances in physical oceanography over the last twenty years. The following items were widely hailed as significant recent achievements: a revolutionary understanding of the coupling of the tropical ocean and atmosphere and the development of predictive El Niño models; estimation of the global distribution of mesoscale variability in the word ocean and theories and models of this geostrophic turbulence; completion of the World Ocean Circulation Experiment and improved estimates of the pathways and timescales of the circulation; and quantitative measurements of the strength of small-scale ocean mixing and the dependence of this mixing on the strength of the internal wave field and other environmental conditions.

The community was also asked to look into the future and forecast advances for the next twenty years. Great excitement was expressed at the prospect of new tools that might solve the problem of observing the global ocean. Already the TOPEX/POSEIDON satellite mission has measured the topography of the sea surface to 3 cm accuracy at 7 km spacing for 5 years. Future developments in satellite oceanography promise global measurements of sea surface salinity and precipitation. These measurements are crucial if we are to understand the climate system and the hydrologic cycle. Yet sea-truth is essential and in situ water-column observations made by an unprecedented class of autonomous instruments are anticipated. Integrating measurements, such as tomography, and the installation of cheap and easy-to-use probes on ships-of-opportunity, hold great promise.

Even with present technology, a description and an understanding of the spatial distribution of turbulent processes in the global ocean is achievable in the next decade. Our present conception of ocean dynamics is largely ignorant of processes with relatively short horizontal length scales (say 100 m to 50 km). Yet biological variability is concentrated on these short scales. It is the dynamics on these same scales that is parameterized by eddy-resolving circulation models. Further, in the coastal zones, cross-shelf exchanges are likely mediated by instabilities and topographic influences whose horizontal scales are much less than those of the well-studied alongshore flows. Exploring these largely unvisited scales is a new frontier for physical oceanography.

Several problems facing physical oceanography were identified at the meeting. These are: (1) large sea-going groups are retrenching and there is a consequent loss of technicians, engineers, and the hardware that these people maintain; (2) sustaining the funding of long time series observations is difficult; (3) physical oceanography is not visible to undergraduate mathematics, physics, and engineering majors, and so does not attract many graduate applicants from that population; (4) the organization of NSF physical ocean