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Scientists at NOAA's National Centers for Environmental Information have released an early update for the World Magnetic Model that powers a variety of global navigational systems.
Over the last few years, Earth's magnetic field has been shifting rapidly. Most recently, the planet's north magnetic pole began lurching toward Siberia. The sudden and dramatic changes weren't anticipated by WMM's previous update.
Every five years, scientists with NOAA and the British Geological Survey update WMM using the latest measurements of Earth's magnetic field. The model uses the latest data to predict how the magnetic field and two magnetic poles will move in the years in-between updates.
"The model is an extrapolation," Arnaud Chulliat, a geophysicist at NCEI, told UPI. "The quality of the model is reflective of the quality of the data."
Magnetic field variation is normal, if not easily predicted, but changes typically don't throw off navigation systems enough to warrant more frequent updates to the model.
Though scientists only update the model every five years, they regularly check its accuracy. Comparing it's predictions to real time measurements on the shifting magnetic field. Too big of a discrepancy can cause navigational errors.
"We've updated the model on a five-year cycle, because in the past, that's the average amount time it takes for the errors to become too large," Chulliat said.
Early last year, scientists realized the errors were getting too big too fast, especially in the Arctic. NOAA and the British Geological Survey decided a more immediate update was necessary. The early update was initially scheduled to be released at the beginning of the January, but the government shutdown forced a delay.
"This out-of-cycle update before next year's official release of WMM 2020 will ensure safe navigation for military applications, commercial airlines, search and rescue operations, and others operating around the North Pole," officials at NCEI wrote in an update.
For decades, magnetic north was steadily inching away from the geographic North Pole, but for the last few years the north magnetic pole has been moving closer to the North Pole. Since the 1990s, magnetic north has been moving considerably faster.
These sporadic changes in direction and speed make it difficult for scientists and the WMM to predict what exactly Earth's magnetic field will look like in five years.
Scientists know the Earth's magnetic field is largely controlled by the movement of iron and nickel inside the planet's outer core, but the precise nature of the mechanism remains a mystery.
"What were are trying to understand is why we had this acceleration in the 1990s," Chulliat said. "They were caused by processes in the core that we don't yet understand."
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