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54 OCEANOGRAPHY IN THE NEXT DECADE 



putational technology will continue to contribute to advances in 

 physical oceanography. 



Studies of climate change put the skills of oceanographers to a 

 severe test. The time scales are long: interannual, decadal, and 

 beyond. Physical processes are three dimensional and involve 

 interaction of the ocean with the atmosphere. Winds transfer 

 momentum and promote mixing and evaporation. Atmospheric 

 temperature influences the density of ocean surface layers through 

 effects on seawater temperature and salinity (through ice forma- 

 tion and melting), which in turn modify the atmosphere. Devel- 

 opment of the physical state of the ocean is difficult to model 

 because it involves the complex interaction of processes that op- 

 erate on vastly different time and space scales. Nonetheless, progress 

 is being made. Techniques that will permit better and more fre- 

 quent observations are being developed, and advances in numeri- 

 cal modeling will soon permit representation of the major compo- 

 nents of ocean circulation. 



Ocean observations reflect the state of the ocean and hence 

 the forces acting on it. Because observations are made in a corro- 

 sive, turbulent environment with high pressures at depth, they 

 are difficult and expensive to obtain. Because of the size and 

 variability of the ocean, measurements are always incomplete in 

 space and time. Yet understanding the ocean depends on adequate 

 measurements, and to make them we need to use technologies 

 that permit a view of the global ocean. Technologies based on 

 acoustics, space-based remote sensing, and underway automatic 

 measurements could all be applied to global-scale observations. 



Predictions of the ocean can be carried out only when the 

 initial and boundary conditions are provided from observations 

 with an accuracy and precision consistent with the physics present. 

 Because oceanic observations are so expensive, models and theo- 

 ries must be used to help determine the most cost-effective mea- 

 surements and measurement systems. 



Global Ocean Observing System 



Physical oceanographic observations and modeling are becom- 

 ing global, but the resources required to deploy and sustain large- 

 scale observations of the world ocean are enormous. The exact 

 configuration of a global ocean observing system is unknown, but 

 it would probably include existing observations from satellites, 

 moored open ocean sensors, volunteer observing ships, and the 

 global sea-level network, as well as other observations that are 



