EarthWatch: Tremendous Tides in Australia’s Broad Sound
Australia’s Broad Sound experiences high tides due to its unique geography.
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- NASA Earth Observatory by Norman Kuring/NASA’s Ocean Color Web, using Landsat data from the U.S. Geological Survey Image of the Day story by Kasha Patel: https://earthobservatory.nasa.gov/images/147567/tremendous-tides-in-broad-sound
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Text, Earth Watch. Exploring the Blue Planet by Satellite
Tremendous Tides in Australia's Broad Sound
A satellite view of the Broad Sound on the Australian coast on October 29, 2020. Text, Across most of Earth's coasts, the difference between high and low tide is typically no more than 2 meters.
In Queensland, Australia's Broad Sound, however, the difference can be as much as 10 meters, the largest tidal range on the country's eastern shore.
Geography plays a key role in this phenomenon.
Like everywhere else on Earth, the tides in Broad Sound are a result of Earth's rotation and the gravitational pull between Earth and the Moon and Sun.
In this region, the tides are amplified by the funnel-like shape of the bay and the proximity of the nearby Great Barrier Reef.
The reef network impedes the normal tidal patterns, concentrating the flows through nearby channels.
The delayed tidal flows from these channels converge in Broad Sound and cause waters to rise significantly.
This image, captured near high tide, shows the dramatic effect of the tidal currents in the sound.
Although no major rivers empty into Broad Sound, the water is filled with sediment stirred up by the extreme ebb and flow of the coastal ocean water.
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