PRESS-NEWS.org - Press Release Distribution
FREE PRESS RELEASES DISTRIBUTION

Warm US West, cold East: A 4,000-year pattern

Global warming may bring more curvy jet streams during winter

Warm US West, cold East: A 4,000-year pattern
2014-04-16
(Press-News.org) SALT LAKE CITY, April 16, 2014 – Last winter's curvy jet stream pattern brought mild temperatures to western North America and harsh cold to the East. A University of Utah-led study shows that pattern became more pronounced 4,000 years ago, and suggests it may worsen as Earth's climate warms.

"If this trend continues, it could contribute to more extreme winter weather events in North America, as experienced this year with warm conditions in California and Alaska and intrusion of cold Arctic air across the eastern USA," says geochemist Gabe Bowen, senior author of the study.

The study was published online April 16 by the journal Nature Communications.

"A sinuous or curvy winter jet stream means unusual warmth in the West, drought conditions in part of the West, and abnormally cold winters in the East and Southeast," adds Bowen, an associate professor of geology and geophysics at the University of Utah. "We saw a good example of extreme wintertime climate that largely fit that pattern this past winter," although in the typical pattern California often is wetter.

It is not new for scientists to forecast that the current warming of Earth's climate due to carbon dioxide, methane and other "greenhouse" gases already has led to increased weather extremes and will continue to do so.

The new study shows the jet stream pattern that brings North American wintertime weather extremes is millennia old – "a longstanding and persistent pattern of climate variability," Bowen says. Yet it also suggests global warming may enhance the pattern so there will be more frequent or more severe winter weather extremes or both.

"This is one more reason why we may have more winter extremes in North America, as well as something of a model for what those extremes may look like," Bowen says. Human-caused climate change is reducing equator-to-pole temperature differences; the atmosphere is warming more at the poles than at the equator. Based on what happened in past millennia, that could make a curvy jet stream even more frequent and-or intense than it is now, he says.

Bowen and his co-authors analyzed previously published data on oxygen isotope ratios in lake sediment cores and cave deposits from sites in the eastern and western United States and Canada. Those isotopes were deposited in ancient rainfall and incorporated into calcium carbonate. They reveal jet stream directions during the past 8,000 years, a geological time known as middle and late stages of the Holocene Epoch.

Next, the researchers did computer modeling or simulations of jet stream patterns – both curvy and more direct west to east – to show how changes in those patterns can explain changes in the isotope ratios left by rainfall in the old lake and cave deposits.

They found that the jet stream pattern – known technically as the Pacific North American teleconnection – shifted to a generally more "positive phase" – meaning a curvy jet stream – over a 500-year period starting about 4,000 years ago. In addition to this millennial-scale change in jet stream patterns, they also noted a cycle in which increases in the sun's intensity every 200 years make the jet stream flatter.

Bowen conducted the study with Zhongfang Liu of Tianjin Normal University in China, Kei Yoshimura of the University of Tokyo, Nikolaus Buenning of the University of Southern California, Camille Risi of the French National Center for Scientific Research, Jeffrey Welker of the University of Alaska at Anchorage, and Fasong Yuan of Cleveland State University.

The study was funded by the National Science Foundation, National Natural Science Foundation of China, Japan Society for the Promotion of Science and a joint program by the society and Japan's Ministry of Education, Culture, Sports, Science and Technology: the Program for Risk Information on Climate Change.

Sinuous Jet Stream Brings Winter Weather Extremes

The Pacific North American teleconnection, or PNA, "is a pattern of climate variability" with positive and negative phases, Bowen says.

"In periods of positive PNA, the jet stream is very sinuous. As it comes in from Hawaii and the Pacific, it tends to rocket up past British Columbia to the Yukon and Alaska, and then it plunges down over the Canadian plains and into the eastern United States. The main effect in terms of weather is that we tend to have cold winter weather throughout most of the eastern U.S. You have a freight car of arctic air that pushes down there."

Bowen says that when the jet stream is curvy, "the West tends to have mild, relatively warm winters, and Pacific storms tend to occur farther north. So in Northern California, the Pacific Northwest and parts of western interior, it tends to be relatively dry, but tends to be quite wet and unusually warm in northwest Canada and Alaska."

This past winter, there were times of a strongly curving jet stream, and times when the Pacific North American teleconnection was in its negative phase, which means "the jet stream is flat, mostly west-to-east oriented," and sometimes split, Bowen says. In years when the jet stream pattern is more flat than curvy, "we tend to have strong storms in Northern California and Oregon. That moisture makes it into the western interior. The eastern U.S. is not affected by arctic air, so it tends to have milder winter temperatures."

The jet stream pattern – whether curvy or flat – has its greatest effects in winter and less impact on summer weather, Bowen says. The curvy pattern is enhanced by another climate phenomenon, the El Nino-Southern Oscillation, which sends a pool of warm water eastward to the eastern Pacific and affects climate worldwide.

Traces of Ancient Rains Reveal Which Way the Wind Blew

Over the millennia, oxygen in ancient rain water was incorporated into calcium carbonate deposited in cave and lake sediments. The ratio of rare, heavy oxygen-18 to the common isotope oxygen-16 in the calcium carbonate tells geochemists whether clouds that carried the rain were moving generally north or south during a given time.

Previous research determined the dates and oxygen isotope ratios for sediments in the new study, allowing Bowen and colleagues to use the ratios to tell if the jet stream was curvy or flat at various times during the past 8,000 years.

Bowen says air flowing over the Pacific picks up water from the ocean. As a curvy jet stream carries clouds north toward Alaska, the air cools and some of the water falls out as rain, with greater proportions of heavier oxygen-18 falling, thus raising the oxygen-18-to-16 ratio in rain and certain sediments in western North America. Then the jet stream curves south over the middle of the continent, and the water vapor, already depleted in oxygen-18, falls in the East as rain with lower oxygen-18-to-16 ratios.

When the jet stream is flat and moving east-to-west, oxygen-18 in rain is still elevated in the West and depleted in the East, but the difference is much less than when the jet stream is curvy.

By examining oxygen isotope ratios in lake and cave sediments in the West and East, Bowen and colleagues showed that a flatter jet stream pattern prevailed from about 8,000 to 4,000 years ago in North America, but then, over only 500 years, the pattern shifted so that curvy jet streams became more frequent or severe or both. The method can't distinguish frequency from severity.

The new study is based mainly on isotope ratios at Buckeye Creek Cave, W. Va.; Lake Grinell, N.J.; Oregon Caves National Monument; and Lake Jellybean, Yukon.

Additional data supporting increasing curviness of the jet stream over recent millennia came from seven other sites: Crawford Lake, Ontario; Castor Lake, Wash.; Little Salt Spring, Fla.; Estancia Lake, N.M.; Crevice Lake, Mont.; and Dog and Felker lakes, British Columbia. Some sites provided oxygen isotope data; others showed changes in weather patterns based on tree ring growth or spring deposits.

Simulating the Jet Stream

As a test of what the cave and lake sediments revealed, Bowen's team did computer simulations of climate using software that takes isotopes into account.

Simulations of climate and oxygen isotope changes in the Middle Holocene and today resemble, respectively, today's flat and curvy jet stream patterns, supporting the switch toward increasing jet stream sinuosity 4,000 years ago.

Why did the trend start then?

"It was a when seasonality becomes weaker," Bowen says. The Northern Hemisphere was closer to the sun during the summer 8,000 years ago than it was 4,000 years ago or is now due to a 20,000-year cycle in Earth's orbit. He envisions a tipping point 4,000 years ago when weakening summer sunlight reduced the equator-to-pole temperature difference and, along with an intensifying El Nino climate pattern, pushed the jet stream toward greater curviness.

INFORMATION:

University of Utah Communications
75 Fort Douglas Boulevard, Salt Lake City, UT 84113
801-581-6773 fax: 801-585-3350
http://www.unews.utah.edu

[Attachments] See images for this press release:
Warm US West, cold East: A 4,000-year pattern Warm US West, cold East: A 4,000-year pattern 2

ELSE PRESS RELEASES FROM THIS DATE:

Scientists achieve first direct observations of excitons in motion

2014-04-16
A quasiparticle called an exciton — responsible for the transfer of energy within devices such as solar cells, LEDs, and semiconductor circuits — has been understood theoretically for decades. But exciton movement within materials has never been directly observed. Now scientists at MIT and the City College of New York have achieved that feat, imaging excitons' motions directly. This could enable research leading to significant advances in electronics, they say, as well as a better understanding of natural energy-transfer processes, such as photosynthesis. The research ...

Wind Over Water Jewelry Project Launch on Indiegogo: Fashion-forward, Baby-friendly and Socially Minded Jewelry Designs For Moms

2014-04-16
Wind Over Water Jewelry designs are exclusively through the Indiegogo Campaign. Providing fashion-forward, baby-friendly and socially-minded jewelry options to mothers. FASHION FORWARD - an upgrade to any outfit plus unique asymmetrical designs always allow mom to remember on what side she last nursed BABY FRIENDLY - materials that are non-toxic plus something that perks baby's interest SOCIALLY MINDED - a partnership that helps impoverished women now plus creates a new future through access to education. That's a lot for a necklace! Fashion-Forward Jewelry Our ...

Richmond Family Dentistry Wins Consecutive Talk of the Town Awards

2014-04-16
For the third straight year, Richmond Family Dentistry has received the prestigious Talk of the Town Customer Satisfaction Award in the Health & Medical -- Dentists. Cheryl Billingsley, DDS, MAGD, ND, and the team at Richmond Family Dentistry were honored with the award after earning the highest possible customer satisfaction rating of 5 stars. The Talk of the Town Awards, presented by Talk of the Town News, honor companies and professionals that provide excellent customer service as reported by their customers through no-cost, user-review websites, blogs, social ...

Florida Matchmaker "Raises the Bar" to help Singles Find Love

2014-04-16
Kelly Leary isn't "your grandmother's matchmaker." In fact, she's brought this ancient talent that goes back thousands of years into the 21st century with her new company, Revolution Dating. "Since the advent of the internet, dating has gotten way more complicated than it ever was," said Leary, who has been a fixture on the matchmaking scene in South Florida and the Treasure Coast for 23 years. "While on the one hand there are more choices than ever, on the other hand you have no idea who you're meeting. Plus, most people don't have the kind of time to waste that internet ...

UNIFOSA Debuts latest 12Gb/s SAS JBOD

2014-04-16
UNIFOSA CORP. launched the 2U 24Bays 12Gb/s SAS JBOD, EP-2246J/JD-SCSC, which offers high density storage, hardware redundancy and easily integrates into versatile applications that request high performance and high scalability. The EP-2246J/JD-SCSC accommodates the latest SAS 3.0 12Gb/s interface which boost up the throughput up to 4,800MB/s per host. Based on this powerful performance, EP-2246J/JD-SCSC can efficiently meet demands for intensive data access applications, virtualization and Windows Server 2012 installation, and video edition related applications. The ...

The Brookeside Group Named 'Customer Service Consulting Practice of the Year' at 2013 Stevie Awards

2014-04-16
The Brookeside Group, a consulting, training and technology firm specializing in client relationship management, took home the Gold Stevie Awards medal for 'Customer Service Consulting Practice of the Year' at the awards ceremony on Feb. 25, 2013 in Las Vegas. The Bostonbased firm was also awarded a Bronze medal for 'Customer Service Training Practice of the Year.' "Winning 'Customer Service Consulting Practice of the Year' is a testament to our commitment to our clients and our continued success helping them create and maintain strong business relationships," said Tom ...

Grand Opening of GreenBliss Lifestyle & Wellness Center

2014-04-16
Bliss Cureton, owner and founder of GreenBliss will open GreenBliss Lifestyle & Wellness store on April 17, 2014. The new retail location is in the Avenue of Fashion District in Detroit and will be one of the many new locally sought after shops. The store will carry an array of non-toxic cleaning supplies, eco-friendly home goods and offer concrete transformation services. The retail store is located in the University District, one of Detroit's most distinguished areas and aims to attract locals who want to live an eco-friendly lifestyle without breaking the bank. ...

Marie Oh Huber Attended 6th Annual DirectWomen Board Institute In New York

2014-04-16
Marie Oh Huber, Senior Vice President, General Counsel and Secretary for Agilent Technologies, Inc., attended the DirectWomen Board Institute from January 22-24 in New York City. DirectWomen, an organization formed to position women lawyers to serve on boards of public companies, selects a group of qualified women lawyers from a competitive pool of applicants across the country to participate in the three-day program. At the DirectWomen Board Institute Huber attended informational sessions on key issues facing current and future corporate directors and had the opportunity ...

Royal Dynamite Launches New Limited Edition Freetown Collection

2014-04-16
Royal Dynamite, a collaborative and unique t-shirt company that combines popular culture and community, is launching the Freetown collection of limited edition t-shirts and hats in time to commemorate Sierra Leone's 53rd Independence Day. Freetown, the capital city of Sierra Leone, was founded in 1792 as a colony for freed slaves by African-Americans, Africans and West Indians. Since its inception in 1792, a lot of historical events have taken place including its independence in 1961 and a 10 year civil war. Today, however, with a new era and powerful generation full ...

Bob Faw's "Energize" Message Reaches Worldwide Audience

2014-04-16
Bob Faw's message of simple yet effective positive change is resonating with people worldwide, driving his book, "Energize: Ignite Passion and Performance With User-Friendly Brain Tools" to No. 1 in two Amazon categories. Eventually ending up as #3 overall in Amazon Kindle Free with more than 34,500 e-book copies downloaded since April 1. "I'm blown away by the response to the book," said Bob. "I love to help people transform their lives in a positive way. It's the most deeply satisfying thing in my life. I wrote 'Energize' because I want to reach more people than I ...

LAST 30 PRESS RELEASES:

Scientists model 'true prevalence' of COVID-19 throughout pandemic

New breakthrough to help immune systems in the fight against cancer

Through the thin-film glass, researchers spot a new liquid phase

Administering opioids to pregnant mice alters behavior and gene expression in offspring

Brain's 'memory center' needed to recognize image sequences but not single sights

Safety of second dose of mRNA COVID-19 vaccines after first-dose allergic reactions

Changes in disparities in access to care, health after Medicare eligibility

Use of high-risk medications among lonely older adults

65+ and lonely? Don't talk to your doctor about another prescription

Exosome formulation developed to deliver antibodies for choroidal neovascularization therapy

Second COVID-19 mRNA vaccine dose found safe following allergic reactions to first dose

Plant root-associated bacteria preferentially colonize their native host-plant roots

Rare inherited variants in previously unsuspected genes may confer significant risk for autism

International experts call for a unified public health response to NAFLD and NASH epidemic

International collaboration of scientists rewrite the rulebook of flowering plant genetics

Improving air quality reduces dementia risk, multiple studies suggest

Misplaced trust: When trust in science fosters pseudoscience

Two types of blood pressure meds prevent heart events equally, but side effects differ

New statement provides path to include ethnicity, ancestry, race in genomic research

Among effective antihypertensive drugs, less popular choice is slightly safer

Juicy past of favorite Okinawan fruit revealed

Anticipate a resurgence of respiratory viruses in young children

Anxiety, depression, burnout rising as college students prepare to return to campus

Goal-setting and positive parent-child relationships reduce risk of youth vaping

New research identifies cancer types with little survival improvements in adolescents and young adul

Oncotarget: Replication-stress sensitivity in breast cancer cells

Oncotarget: TERT and its binding protein: overexpression of GABPA/B in gliomas

Development of a novel technology to check body temperature with smartphone camera

The mechanics of puncture finally explained

Extreme heat, dry summers main cause of tree death in Colorado's subalpine forests

[Press-News.org] Warm US West, cold East: A 4,000-year pattern
Global warming may bring more curvy jet streams during winter