Coastal Circulation

A.J. Souza, I.J. Mariño-Tapia, J.D. Pietrzak, D. Prandle

Treatise on Estuarine and Coastal Science (Second Edition), Volume 2, 2024, Pages 321-367

ttps://doi.org/10.1016/B978-0-323-90798-9.00080-9

Abstract
This chapter indicates how tides, density gradients, winds, and waves generate residual circulation in the coastal zone. The present focus is primarily on tidally dominated regimes, although we will also look at wave-driven circulation in the Mexican Caribbean. Primary attention is on the relationship between the above forcing and the resultant dynamics (currents), the further issue of the interconnected impacts on turbulence, mixing, and stratification is described more fully in Chapters 2.02 and 2.05. In comparison with the primary forcing components, the energy content of these residual circulations may seem negligible. However, such circulations strongly influence the longer-term supply to and disposal from estuaries of salt, heat, sediments, nutrients, etc. While the associated horizontal distribution patterns clearly influence these exchanges, the vertical distributions of temperature and salinity generate significant density gradients that often result in opposing export and import of tracers between the surface and bed.
In this chapter, we focus primarily on semi-enclosed systems. In more exposed seas not discussed here, such as the Yucatan Shelf, the Brazilian Shelf, the Maine coast, and the California coast, ocean-shelf interactions may play a significant role.