adplus-dvertising
Connect with us

Science

How the moon's 'wobble' worsens coastal flooding | University of Hawaiʻi System News – UH System Current News

Published

 on


High tide nuisance flooding in Miami, Florida. (Photo credit: B137, CC BY-SA 4.0, via Wikimedia Commons)

This editorial by University of Hawaiʻi at Mānoa Assistant Professor Philip R. Thompson was posted in The Hill on July 20, 2021.

Full moon, new moon. High tide, low tide. These are dependable rhythms of our planet. It is not surprising then, that news of a “wobble” in the moon’s orbit—one with implications for the growing problem of U.S. coastal flooding — has piqued the curiosity of many.

So, what exactly is this “wobble?” The word wobble suggests a breakdown in the regular and predictable motion of the moon and its influence on the tides. This is not the intended meaning, though. What the media has termed the ”wobble” is actually a cycle as regular as the seasons but occurring over decades rather than months. More specifically, the path of the moon’s orbit around Earth is tilted in space and rotates once every 18.6 years with a motion similar to the undulations of a spinning coin just before it falls flat. This motion is more precisely described as lunar nodal precession, and it is most certainly not a new discovery. Astronomers have observed this phenomenon for millennia by documenting gradual changes to the moon’s position in the night sky.

Precession of the moon’s orbit is not merely an astronomical phenomenon—it also affects ocean tides, which is how this esoteric “wobble” is connected to coastal flooding and made it into the headlines. The effect of precession on tides is not the same everywhere: To get an idea of the size of the effect, consider St. Petersburg, Florida, where the height of the highest tides changes over the lunar precession cycle by a little less than two inches. That may not seem like much, but keep in mind that the total amount of global average sea-level rise over the last decade is also a little less than two inches. That means that the “wobble” has roughly the same impact on the height of high tides as the most recent decade of global sea-level rise.

These seemingly small changes can have big consequences because high-tide flooding is a game of inches, where benign high water levels suddenly become impactful as the edge of a storm drain or sea wall is breached. Not to mention that the extent and frequency of such events increases rapidly with every incremental increase in the height of high tides. In St. Petersburg, for example, increasing the height of high tides by four inches (similar to the influence of the “wobble” plus a decade of sea-level rise) can produce an increase from 10 high-tide floods per year to 45 floods per year. That same four inches in Honolulu, Hawaii can produce an increase from 10 to almost 70 high-tide floods per year. Inches matter.

Of course, this is not the sort of extreme flooding that makes good fodder for a Hollywood climate-disaster film. Instead, high-tide flooding can occur on a sunny, otherwise normal day and result in impacts like minor erosion; backed up drainage and sewage systems; and/or standing water in roads, parking lots and basements.

We should be careful, though, not to confuse lack of total destruction for lack of importance. This is often a challenge in communicating the real-world, incremental impacts of ongoing climate change. High-tide flooding may not produce the next Atlantis, but it will cause an insidious accumulation of seemingly minor economic and infrastructural consequences. The impact will become acute as more and more events occur over increasingly narrow windows of time.

Planning for any aspect of climate change requires acknowledging and understanding the interplay between natural cycles and human-induced climate trends. Both exist, and the existence of one does not preclude the other. A decade-long global warming “pause,” for example, does not mean that a century-long warming trend is not happening.

Similarly, my research team has shown that precession of the moon’s orbit will at times act to slow (and perhaps even pause) increasing frequency of high-tide flooding due to sea-level rise. But we also know that the opposite will occur, and many U.S. coastal communities will experience periods of rapid increase in high-tide flooding when the cyclical “wobble” acts to enhance the effects of sea-level rise.

Our work specifically points to the mid-2030s as the onset of one such period of rapid change. Under the NOAA Intermediate scenario for sea-level rise, we project that a majority of coastal locations in the Gulf of Mexico, California and Hawaiʻi will experience at least a quadrupling and as much as a ten-fold increase in the frequency of high-tide floods over a 10-year period beginning in the 2030s. These communities will join the many places along the U.S. East Coast that already experience recurrent flooding at high tide, transforming a regional problem into a national issue.

To make matters worse, the onset of this rapid change will come on the heels of a period during which the cyclical “wobble” will suppress increases in high-tide flooding due to sea-level rise. It is essential that affected communities are not complacent during the period of slow change in order to avoid being caught off guard by the rapid change to follow. Fortunately, we can point to a specific natural cycle to predict and explain what is happening, but continued reminders will be necessary.

In Hawaiʻi, where I live, there is a proverb: I Kahiki ka ua, ako ʻē ka hale, which means “while the rain is far away, thatch the house.” The mid-2030s are not all that far away, and the infrastructure projects needed to mitigate the impacts of increased high-tide flooding will take time and resources.

Now is the time to acknowledge the changes we are observing, to be realistic about what’s to come, and to get to work ensuring that our coastal communities are resilient and thrive in the coming decades.

—Philip R. Thompson, is an assistant professor in the Department of Oceanography at University of Hawaiʻi at Mānoa and director of the UH Sea Level Center. He is the lead author of a recent study that generated headlines by showing how a natural cycle in the moon’s orbit affects future coastal flooding due to sea-level rise.

Adblock test (Why?)

728x90x4

Source link

Continue Reading

News

Here’s how Helene and other storms dumped a whopping 40 trillion gallons of rain on the South

Published

 on

 

More than 40 trillion gallons of rain drenched the Southeast United States in the last week from Hurricane Helene and a run-of-the-mill rainstorm that sloshed in ahead of it — an unheard of amount of water that has stunned experts.

That’s enough to fill the Dallas Cowboys’ stadium 51,000 times, or Lake Tahoe just once. If it was concentrated just on the state of North Carolina that much water would be 3.5 feet deep (more than 1 meter). It’s enough to fill more than 60 million Olympic-size swimming pools.

“That’s an astronomical amount of precipitation,” said Ed Clark, head of the National Oceanic and Atmospheric Administration’s National Water Center in Tuscaloosa, Alabama. “I have not seen something in my 25 years of working at the weather service that is this geographically large of an extent and the sheer volume of water that fell from the sky.”

The flood damage from the rain is apocalyptic, meteorologists said. More than 100 people are dead, according to officials.

Private meteorologist Ryan Maue, a former NOAA chief scientist, calculated the amount of rain, using precipitation measurements made in 2.5-mile-by-2.5 mile grids as measured by satellites and ground observations. He came up with 40 trillion gallons through Sunday for the eastern United States, with 20 trillion gallons of that hitting just Georgia, Tennessee, the Carolinas and Florida from Hurricane Helene.

Clark did the calculations independently and said the 40 trillion gallon figure (151 trillion liters) is about right and, if anything, conservative. Maue said maybe 1 to 2 trillion more gallons of rain had fallen, much if it in Virginia, since his calculations.

Clark, who spends much of his work on issues of shrinking western water supplies, said to put the amount of rain in perspective, it’s more than twice the combined amount of water stored by two key Colorado River basin reservoirs: Lake Powell and Lake Mead.

Several meteorologists said this was a combination of two, maybe three storm systems. Before Helene struck, rain had fallen heavily for days because a low pressure system had “cut off” from the jet stream — which moves weather systems along west to east — and stalled over the Southeast. That funneled plenty of warm water from the Gulf of Mexico. And a storm that fell just short of named status parked along North Carolina’s Atlantic coast, dumping as much as 20 inches of rain, said North Carolina state climatologist Kathie Dello.

Then add Helene, one of the largest storms in the last couple decades and one that held plenty of rain because it was young and moved fast before it hit the Appalachians, said University of Albany hurricane expert Kristen Corbosiero.

“It was not just a perfect storm, but it was a combination of multiple storms that that led to the enormous amount of rain,” Maue said. “That collected at high elevation, we’re talking 3,000 to 6000 feet. And when you drop trillions of gallons on a mountain, that has to go down.”

The fact that these storms hit the mountains made everything worse, and not just because of runoff. The interaction between the mountains and the storm systems wrings more moisture out of the air, Clark, Maue and Corbosiero said.

North Carolina weather officials said their top measurement total was 31.33 inches in the tiny town of Busick. Mount Mitchell also got more than 2 feet of rainfall.

Before 2017’s Hurricane Harvey, “I said to our colleagues, you know, I never thought in my career that we would measure rainfall in feet,” Clark said. “And after Harvey, Florence, the more isolated events in eastern Kentucky, portions of South Dakota. We’re seeing events year in and year out where we are measuring rainfall in feet.”

Storms are getting wetter as the climate change s, said Corbosiero and Dello. A basic law of physics says the air holds nearly 4% more moisture for every degree Fahrenheit warmer (7% for every degree Celsius) and the world has warmed more than 2 degrees (1.2 degrees Celsius) since pre-industrial times.

Corbosiero said meteorologists are vigorously debating how much of Helene is due to worsening climate change and how much is random.

For Dello, the “fingerprints of climate change” were clear.

“We’ve seen tropical storm impacts in western North Carolina. But these storms are wetter and these storms are warmer. And there would have been a time when a tropical storm would have been heading toward North Carolina and would have caused some rain and some damage, but not apocalyptic destruction. ”

___

Follow AP’s climate coverage at https://apnews.com/hub/climate

___

Follow Seth Borenstein on Twitter at @borenbears

___

Associated Press climate and environmental coverage receives support from several private foundations. See more about AP’s climate initiative here. The AP is solely responsible for all content.

Source link

Continue Reading

Science

‘Big Sam’: Paleontologists unearth giant skull of Pachyrhinosaurus in Alberta

Published

 on

 

It’s a dinosaur that roamed Alberta’s badlands more than 70 million years ago, sporting a big, bumpy, bony head the size of a baby elephant.

On Wednesday, paleontologists near Grande Prairie pulled its 272-kilogram skull from the ground.

They call it “Big Sam.”

The adult Pachyrhinosaurus is the second plant-eating dinosaur to be unearthed from a dense bonebed belonging to a herd that died together on the edge of a valley that now sits 450 kilometres northwest of Edmonton.

It didn’t die alone.

“We have hundreds of juvenile bones in the bonebed, so we know that there are many babies and some adults among all of the big adults,” Emily Bamforth, a paleontologist with the nearby Philip J. Currie Dinosaur Museum, said in an interview on the way to the dig site.

She described the horned Pachyrhinosaurus as “the smaller, older cousin of the triceratops.”

“This species of dinosaur is endemic to the Grand Prairie area, so it’s found here and nowhere else in the world. They are … kind of about the size of an Indian elephant and a rhino,” she added.

The head alone, she said, is about the size of a baby elephant.

The discovery was a long time coming.

The bonebed was first discovered by a high school teacher out for a walk about 50 years ago. It took the teacher a decade to get anyone from southern Alberta to come to take a look.

“At the time, sort of in the ’70s and ’80s, paleontology in northern Alberta was virtually unknown,” said Bamforth.

When paleontogists eventually got to the site, Bamforth said, they learned “it’s actually one of the densest dinosaur bonebeds in North America.”

“It contains about 100 to 300 bones per square metre,” she said.

Paleontologists have been at the site sporadically ever since, combing through bones belonging to turtles, dinosaurs and lizards. Sixteen years ago, they discovered a large skull of an approximately 30-year-old Pachyrhinosaurus, which is now at the museum.

About a year ago, they found the second adult: Big Sam.

Bamforth said both dinosaurs are believed to have been the elders in the herd.

“Their distinguishing feature is that, instead of having a horn on their nose like a triceratops, they had this big, bony bump called a boss. And they have big, bony bumps over their eyes as well,” she said.

“It makes them look a little strange. It’s the one dinosaur that if you find it, it’s the only possible thing it can be.”

The genders of the two adults are unknown.

Bamforth said the extraction was difficult because Big Sam was intertwined in a cluster of about 300 other bones.

The skull was found upside down, “as if the animal was lying on its back,” but was well preserved, she said.

She said the excavation process involved putting plaster on the skull and wooden planks around if for stability. From there, it was lifted out — very carefully — with a crane, and was to be shipped on a trolley to the museum for study.

“I have extracted skulls in the past. This is probably the biggest one I’ve ever done though,” said Bamforth.

“It’s pretty exciting.”

This report by The Canadian Press was first published Sept. 25, 2024.

The Canadian Press. All rights reserved.

Source link

Continue Reading

News

The ancient jar smashed by a 4-year-old is back on display at an Israeli museum after repair

Published

 on

 

TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.

Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.

Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.

The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.

The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.

It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.

Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.

Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.

Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.

Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.

Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.

The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”

The Canadian Press. All rights reserved.

Source link

Continue Reading

Trending