The worldwide coastal ocean exhibits vast geographical diversity, 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-meteorological processes that to some extent act on all the world shelves and coastal waters. Each physical process and its effects on the biology, 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 interdisciplinary 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.
The atmosphere is a major driving force of coastal ocean processes, through both its role in driving currents and its direct and indirect controls on biological and chemical processes. For example, wind-driven coastal upwelling can provide nutrients to the euphotic zone, leading to enhanced primary productivity, and atmospherically generated turbulence can increase predator-prey encounters among plankton (Rothschild and Osborn, 1988). Each of these biological processes results in distinct chemical transformations 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 currents 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. Interaction of the atmosphere with the coastal ocean on these important scales of tens to hundreds of kilometers is not well-understood.