Earth’s Magnetic Field Affecting The Navigation Of Ships

By: Tejeshwar Singh Rana, Chief Officer, Shell shipping-London, UK & Associate Editor-ICN

Scientists know the earth can undergo phenomenon known as “geomagnetic reversal”, where these magnetic pole literally switch sides.

The planet’s magnetic field is up to mischief again and geologists are pretty dumbfounded. Earth’s magnetic poles can wander several kilometers every year, however, the north pole’s movement has become incresingly stranger in recent years. For reasons that are currently unclear, the magnetic north pole seems to be increasingly slipping away from Canada and towards Siberia at an erratic rate, according to reports.

The location of the north magnetic pole appears to be governed by two large scale patches of magnetic field, one beneath Canada and one beneath Siberia.

Every five years, the national oceanic and atmospheric administration(NOAA)maps out the earth’s magnetic field in the world’s magnetic model(WMM). This was last published in 2015, with the next edition planned for 2020, but this freak behavior forced scientists to revive the map earlier than anticipated. Unfortunately, the revamped WMM was supposed to be released on January 15 2019, but its been postponed until January 30 2019 due to ongoing government shutdown.

It’s a fairly chaotic situation in there, resulting in a complex pattern of magnetism which can prove extremely difficult to model and predict. Just to make things even more complicated, an unusually punchy geomagnetic pulse occurred under South America in 2016, which is believed to have contributed to the recent unexpected changes. However, it largely remain unclear why the magnetic field appearing to weaken in such a strange way.

You might be wondering whether any of this matters. Well, the magnetic field is central to many forms of navigation. Most obviously, a ship’s compass relies on magnetic fields, but more advanced systems of navigation use the field as a bearing too. The ship’s compass has error due to variation and deviation errors.

Variation is due to Earth’s  magnetic field at various locations on Earth and it cannot be controlled,and if the Earth’s magnetic poles will wander then definitely this will also effect the Ship’s magnetic compass and Navigation related issues will come such as compass bearing will differ with a big margin to the true bearing, and as we know ships navigate with compass.

These currently anomalies shouldn’t be strong enough to completely screw this up, however , it’s most certainly something geologists need to keep on top of. Indeed, it is possible for truly monstrous changes to the magnetic field to take place. Scientists know the earth can undergo phenomenon known as “geomagnetic reversal”, where these magnetic pole literally switch sides.The last time this happened was 781000 years ago, but its believed to have occurred every 20000-30000 years over the last 20 million years.

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