Page 10 - PR Mag Sep19

time and tide:

HOW THE MOON AND OTHER FACTORS AFFECT OUR OCEANS

We all know that tides are influenced by the Moon, but how does that connection work and

how can we predict the tides more than a year in advance?

They are just two of many questions the Bureau of Meteorology Just to make the job more complicated, the Moon’s effect on
answered during this year’s National Science Week (which sea levels can vary from one location to another.
ran 10-18 August), with the theme: Destination Moon: more “The shape of the coastline and depth of bays along with the
missions, more science. positions of the moon, sun and planets are all factors that make
The Bureau provides the tide forecasts which are an essential the tidal range and frequency vary at different places around
tool for everyone from recreational fishers to the operators of the world.
giant container ships. “On top of this, weather (both nearby and remote) and ocean
And while we rely on weather forecasts for up to a week in circulation dynamics also affect the total sea level along
advance, many take for granted that tide tables can be relied coastlines. Where the tidal range is small, sometimes it is these
on for well over a year. other factors that have the bigger effect,” she said.
Bureau of Meteorology Ocean Analyst Jessica Sweeney says Dredging Manager Frans Schlack from Pilbara Ports Authority
the tide in any place is affected by the moon and several says knowing what the sea level will be, ahead of time,
other factors. influences multi-million-dollar decisions every day.
“Gravitational forces of the earth, moon and sun drives the “If it wasn’t for accurate tide predictions, we couldn’t operate
tide, but few people know that the combination of these forces safely and efficiently at the Port of Port Hedland, the world’s
sloshes the deep ocean water back and forth. largest bulk export port.” he said.
“The resulting long waves then move around the globe and So, when you look up at the night sky, just remember, the
interact with the continental land masses. Calculating these Moon may be more powerful than you thought.
effects at the coast is complex,” she said.