adplus-dvertising
Connect with us

Science

New research provides unprecedented look at what influences sea ice motion in the Arctic

Published

 on

Local tidal currents strongly affect the movement of sea ice in the Arctic ocean and the makeup of the seafloor causes some of the most abrupt changes. Credit: Daniel Watkins.

A new study led by researchers at Brown University offers fresh insights into the forces above and beneath the ocean surface that influence how sea ice moves and disperses in the Arctic Ocean, which is warming at over twice the rate of the global average.

The in-depth analysis reveals how local tidal currents strongly affect the movement of the ice along its journey and provides an unprecedented look at how the makeup of the sea floor is causing some of the most abrupt changes.

Data from the study can be applied to improve complex computer simulations used for forecasting Arctic sea ice conditions, and in the long-term, the results may help clarify how is altering the Arctic and inform future climate predictions.

“The ice is clearly feeling the influence of the bottom of the ocean,” said Daniel Watkins, a postdoctoral researcher at Brown and lead author of the new study published in Geophysical Research Letters. “The landscape at the , like canyons and , affects tides and other ocean currents. And as it drifts, the sea ice passes over many different undersea features. We see sharp changes in the dynamics of the sea ice as soon as it gets to those undersea features.”

Using data from the largest ever drifting sea-ice buoy array, along with 20 years of satellite images, the researchers examined sea ice motion as it drifted from the Arctic Ocean through a deep-water passage called the Fram Strait and eventually into the Greenland Sea. The analysis revealed the sea floor’s impact on some of the most abrupt changes affecting the sea ice, like dramatic gains in speed or motions that force the ice to pack in close together or even break apart.

“What we see with this data set is a transition from the central Arctic, where the ice is mostly moving as a whole and following wind patterns, to areas where we’re seeing much stronger impacts of ocean currents,” Watkins said.

The Arctic is the fastest warming part of the globe and it has long been understood that sea ice in the region plays an important role in the planet’s climate. For instance, the ice acts like a reflective surface deflecting how much sunlight is absorbed by Earth. As it disappears, more sunlight is absorbed, leading to a warmer planet. Many scientists also expect that as Arctic ice vanishes, weather across the Northern Hemisphere will be impacted, producing periods of bitter cold, punishing heat waves and disastrous floods.

With the study, the researchers wanted to delve deeper into the changes happening in this critically important part of Earth. Much of the data for the study was gathered during the largest polar expedition in history—the Multidisciplinary drifting Observatory for the Study of Arctic Climate.

Comprehensive research reveals sudden increases in ice speed

During the expedition, teams of researchers took turns spending a year drifting with the sea ice aboard a massive German icebreaker in the Arctic Ocean. Watkins was there for two weeks in October 2019 to help install a network of autonomous sensors around the base camp. While there, Watkins coordinated helicopter flights to remote patches of sea ice, worked with analysts to find suitable sites for instruments and buoys, and deployed them on the ice.

Throughout the year-long expedition, 214 buoys were deployed, including 51 during Watkins’ tenure on the expedition. The study is based on GPS data transmitted from a set of 108 of the buoys that drifted from the central Arctic through the Fram Strait and into the Greenland Sea.

The was on what are known as marginal ice zones in the Greenland Sea and Fram Strait, which is the transition zone between the open, ice-free ocean and the pack ice of the central Arctic.

As part of their analysis, the group also analyzed satellite measurements taken from 2003 to 2020 to put the data the buoys gathered over the year adrift into historical context. The satellite data helped confirm sharp changes in ice velocity and ice motion that could only be explained by the sea floor’s influence on the sea ice.

For instance, looking at the data from an area northeast of Svalbard, Norway, the researchers noticed the speed of the ice suddenly increased even though the wind hadn’t changed. That meant the ice was getting pushed by the ocean currents, so the team delved deeper to find where this happens and how.

They found that the sea ice speeds up where the Transpolar Drift Stream, one of the Arctic’s Ocean major currents, ends and the fast-moving East Greenland Current, which forms due to a combination of Earth’s rotation and the edge of the continental shelf on the sea floor, begins. The analysis shows how the sea ice responds to different and that the sea floor plays a role.

“In the beginning of this journey, there was almost no difference in the drift speed across the whole set of buoys,” Watkins said. “Then there’s essentially one day where the wind died down and the ice ran into that boundary current and it just took off. It was like a one-day-to-the-next change in what was pushing the ice.”

As next steps, the researchers plan to work with model developers to help implement the data from the study into forecasts of how the ice will move and where it will end up. They also plan to further develop an ice floe tracking tool to track the motion of individual pieces of ice. The tool would help researchers see details of ice motion that are invisible to standard approaches.

“We’re hoping to understand the changing ice physics in a warming Arctic and use it to help make our models of those physics better,” Watkins said.

Along with Watkins, other researchers involved with the study included Monica Martinez Wilhelmus, an assistant professor of engineering and a senior author on the study, as well as Angela C. Bliss from NASA’s Goddard Space Flight Center and Jennifer K. Hutchings from Oregon State University.

More information:
Daniel M. Watkins et al, Evidence of Abrupt Transitions Between Sea Ice Dynamical Regimes in the East Greenland Marginal Ice Zone, Geophysical Research Letters (2023). DOI: 10.1029/2023GL103558

Provided by
Brown University

 

Citation:
New research provides unprecedented look at what influences sea ice motion in the Arctic (2023, August 16)
retrieved 17 August 2023
from https://phys.org/news/2023-08-unprecedented-sea-ice-motion-arctic.html

This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no
part may be reproduced without the written permission. The content is provided for information purposes only.

 

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