Posts Tagged ‘Bernard Brunhes’
“Hurricane season brings a humbling reminder that, despite our technologies, most of nature remains unpredictable”*…
Still, as Katarina Zimmer explains, an emerging science can help us improve our forecasts…
… contemporary simulations suggest the Great Colonial Hurricane was a Category 3.5 storm, probably the strongest in recorded eastern New England history. (For reference, Sandy, which killed nearly 150 people and caused some $65 billion in damage in the United States, was technically no longer even a hurricane when it made landfall in the New York metro area in 2012.)
Scientists know about the Great Colonial Hurricane’s impact not only from written reports but curiously, also from hidden, physical impressions the long-ago storm left on the landscape.
At the bottom of a pond, Jeffrey Donnelly, a hurricane scientist at the Woods Hole Oceanographic Institution, and his colleagues found subtle, buried evidence of the storm that almost felled the Mather line. The researchers were collecting sediment cores from a lakebed on Cape Cod. The spot, known as Salt Pond, lies about a third of a mile from the ocean and has long been a place of mud. But in their core samples, they found a pinky finger-thick layer of pure ocean sand in layers that dated back to roughly 1635. The only thing that could have pulled that much beach material over the sand barrier and that far inland was a truly massive storm.
The cores revealed other clues, too. Although written accounts suggest the 1635 tempest was the strongest of its time, the exhumed samples showed it wasn’t the only intense storm in the area. Donnelly found evidence for 10 major storms in the area between 1400 and 1675—a surprising toll, given that major hurricanes are virtually unheard of this far north today. The fact that hurricanes were much more frequent in the past begs the question of why, and whether these levels of storm activity could someday return.
Which is why researchers like Donnelly are traipsing along coastlines and digging in the muck. They hope their relatively new branch of science, paleotempestology (the study of old storms), can use these buried traces of long-gone winds to augur ancient patterns. Patterns that might also help us predict the weather that lies ahead…
Paleotempestology promises to uncover patterns of historical hurricanes—to better predict destructive weather of the future. More at: “The Secret Messages in Ancient Storms,” (or here) from @katarinazimmer in @NautilusMag.
* Diane Ackerman
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As we muse on the meteorological, we might send exploratory birthday greetings to Bernard Brunhes; he was born on this date in 1867. A geophysicist, he is known for his pioneering work in paleomagnetism, in particular, his 1906 discovery of geomagnetic reversal [see here]. The current period of normal polarity, Brunhes Chron, and the Brunhes–Matuyama reversal are named for him.
Brunes made his discovery in a way that presaged the work of paleotempestologists: he found volcanic lava and clay samples that recorded the Earth’s inversion of its magnetic field.
“We never cease to stand like curious children before the great mystery into which we were born”*…
This animation shows the movement of the north magnetic pole at 10-year intervals from 1970 to 2020. The red and blue lines indicate “declination,” the difference between magnetic north and true north depending on where one is standing; on the green line, a compass would point to true north. Visual by NOAA National Centers for Environmental Information
In scenario planning, one tries to identify the “driving forces”– the social, political, ecological, technical, and economic dynamics afoot– in the environment that are both likely to impact our future materially and outside our control; one then to knits the possible outcomes of those forces into alternative futures, plausible sketches of the opportunities and challenges that one might face.
There is a special class of driving force, what scenario planners call a wild card: a possibility that has relative low probability in the (usually 10 year) time horizon, but that, should it occur, would have massive consequence. Wild cards are often things like major earthquakes or geo-political conflicts… or environmental catastrophes. While one plans for the implications of the scenarios and their defining driving forces, one plans against wild cards; one creates action plans for the scenarios, contingency plans for the wild cards.
As climate change is slowly but surely converting yesterday’s wildcards (sustained droughts, regular, catastrophic wildfires and storms, etc.) into “regular” driving forces, it is perhaps prudent to look at some of the wildest cards that remain…
One day in 1905, the French geophysicist Bernard Brunhes brought back to his lab some rocks he’d unearthed from a freshly cut road near the village of Pont Farin. When he analyzed their magnetic properties, he was astonished at what they showed: Millions of years ago, the Earth’s magnetic poles had been on the opposite sides of the planet. North was south and south was north. The discovery spoke of planetary anarchy. Scientists had no way to explain it.
Today, we know that the poles have changed places hundreds of times, most recently 780,000 years ago. (Sometimes, the poles try to reverse positions but then snap back into place, in what is called an excursion. The last time was about 40,000 years ago.) We also know that when they flip next time, the consequences for the electrical and electronic infrastructure that runs modern civilization will be dire. The question is when that will happen…
The shield that protects the Earth from solar radiation is under attack from within. We can’t prevent it, but we ought to prepare. Learn more at “The Magnetic Field Is Shifting. The Poles May Flip. This Could Get Bad.”
* Albert Einstein
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As we ponder powerlessness, we might recall that it was on this date in 1697 that Isaac Newton received a copy of Johann Bernoulli’s long-standing mathematical challenge, the brachistochrone problem: “To determine the curved line joining two given points, situated at different distances from the horizontal and not in the same vertical line, along which the mobile body, running down by its own weight and starting to move from the upper point, will descend most quickly to the lower point.” (Bernoulli coined the name from Gr. brachistos, shortest; and chronos, time.)
Newton solved it the same day, and forwarded his solution to the Royal Society—anonymously. When Bernoulli read the solution, he shrewdly guessed it was Newton’s work. By legend, he said, “I recognize the lion by his paw.”
Bernoulli and Newton
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