NOAA's National Ocean Service: Low tide

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Tides establish complex patterns within each ocean basin that often differ greatly from tidal patterns of adjacent ocean basins or other regions of the same ocean basin (Sumich, J.L., 1996). This map shows the geographic distribution of different tidal cycles along the earth's coastlines. Areas experiencing diurnal tides are marked in yellow, areas experiencing semidiurnal tides are drawn in red and regions with mixed semidiurnal tides are outlined in blue.