Published online by Cambridge University Press: 18 December 2009
Introduction
This chapter provides some background into our understanding and modeling of astronomical tides in coastal basins. We provide some simple models that illustrate some of the basic scientific ideas and methodology models of tides and long waves. We finish the chapter with some general comments on the way that we build spatial grids for numerical models.
Astronomical tides
Origin of tides
The astronomical tides of the ocean are primarily due to changes in the gravitational potential exerted on the large ocean basins by the Moon and Sun as the Earth rotates in their gravitational fields. These are called astronomical tides by oceanographers. The word tide in common parlance refers to any movement of ocean water or change in ocean state. Thus, we find the noun tide being used to describe phenomena in the coastal ocean, such as the state and direction of currents important to maritime operations, water height and also red tides, rip tides, etc., and there are many etymological links between the words tide and time. In oceanography tide is used in general to refer to any periodic changes in water level and the associated current; these may be due to astronomical forcing or to other processes, such as periodic winds. However, oceanographers often use the term tides as a synonym for astronomical tides, since these tides are a dominant feature of the world's oceans. There has been an attempt to tidy up, within earth sciences, the use of the word tide.
To save this book to your Kindle, first ensure [email protected] is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Find out more about the Kindle Personal Document Service.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Dropbox.
To save content items to your account, please confirm that you agree to abide by our usage policies. If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account. Find out more about saving content to Google Drive.