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116 OCEANOGRAPHY IN THE NEXT DECADE 



Future Directions 



The worldwide coastal ocean exhibits vast geographical diver- 

 sity, depending on the size and openness of bays and estuaries; the 

 width of the continental shelf; the proximity of strong oceanic 

 currents; the strength of tides, winds, river runoff, and surface 

 heat fluxes; and other characteristics. It is clearly impractical to 

 explore fully the biological, chemical, geological, meteorological, 

 and physical structure and variability of every estuary or shelf 

 region of the United States, let alone of the world. One way to 

 proceed is to identify the most significant physical-meteorologi- 

 cal processes that to some extent act on all the world shelves and 

 coastal waters. Each physical process and its effects on the biol- 

 ogy, chemistry, and geology of the local area could then be studied 

 in a prototypical environment (not limited to U.S. waters) where 

 the process tends to predominate. The results of such interdiscipli- 

 nary studies could be used to improve our modeling capabilities, 

 enhancing our ability to model more typical shelves or estuaries 

 where a combination of processes interacts. Although this approach 

 is not a panacea, it can at least define the information needed to 

 gain a desired level of understanding of a given coastal region. Within 

 this broad approach to the coastal ocean, a number of important 

 themes will be common to any detailed study of processes. 



Air-Sea Interactions 



The atmosphere is a major driving force of coastal ocean pro- 

 cesses, through both its role in driving currents and its direct and 

 indirect controls on biological and chemical processes. For ex- 

 ample, wind-driven coastal upwelling can provide nutrients to the 

 euphotic zone, leading to enhanced primary productivity, and at- 

 mospherically generated turbulence can increase predator-prey 

 encounters among plankton (Rothschild and Osborn, 1988). Each 

 of these biological processes results in distinct chemical transfor- 

 mations as well. 



Present knowledge of atmospheric effects on the coastal ocean 

 is limited to the effects of large-scale (500-kilometer) atmospheric 

 features. This knowledge is useful for predicting alongshore cur- 

 rents or estimating the transport of dust particles from land to 

 ocean (eolian deposition). Smaller scales in the wind field seem 

 to be more important in determining cross-shelf currents; yet small- 

 scale coastal winds are poorly observed and understood. Interac- 

 tion of the atmosphere with the coastal ocean on these important 

 scales of tens to hundreds of kilometers is not well-understood. 



