Ocean Tides and Amphidromic Systems

Tidal Forces

Tides -- we immediately think of the periodic rise and fall in sea level, observed along coastlines around the world. Tides also mean a repeated cycle of ebb and flood as the currents change their direction and speed.

  • Why do we have tides?

  • Why are the amplitudes and phases of tides different, depending on location?

  • How does the tide propagate around the world, or across a basin?

  • What influence does the tide have on a larger scale?

Historic tidal gauge near Anchorage, indicating the extreme tidal range possible along fiords in Southeast and South-central Alaska. (NOAA/NOS Tides and Currents)
Tidal Components
Equilibrium Theory
Dynamic Theory
Amphidromic Systems
Tide Waves
Closed Basins & Channels
Arctic & Antarctic Tides


Author: E. Boyce
Created: 7 December, 2003
Web project for PHYS645 Fundamentals of Geophysical Fluid Dynamics, University of Alaska Fairbanks