How Arctic Warming Can Cause Cold Waves in North America – New Research Builds Relationships – WKRG News 5

February 2021 Rapidly warming global temperatureA very severe cold wave struck much of North America, from Canada to northern Mexico. It did not empower 10 million people.The impact is Especially tough in Texas, That alone resulted in more than 125 deaths associated with the event.

in America, The coldest February in over 30 years..Cold waves in the country The most expensive winter storm on record..

Sub-zero temperatures were associated with a southward decline. Jet streamA band of strong winds about eight miles above the surface of the Earth, associated with the boundary between cold and warm air.

Jet streams flow from west to east, but that’s not the only direction atmospheric waves can move. Atmospheric waves can also travel long distances up and down, linking the weather and climate of a region, such as the Arctic Circle, as follows: Other regions like Texas.

Surface temperature in Texas at 6 am on February 15, 2021. The black line shows the jet stream and the white line shows the degree of freezing temperature. Matthew Barlow / University of Massachusetts Lowell, CC BY-ND

you Throw a rock into the pondYou can see that the ripples – waves – expand away from the initial disturbance. Pond ripples are a different type of wave than a jet stream dip, but both types of waves can transmit the effects of disturbances to distant areas.

The water undulates in response to the disturbance. Forance / Shutterstock.

In this case, atmospheric waves transmitted the effects of Arctic climate change to North America and parts of Asia.

so Study published on September 2, 2021, In the journal ChemistryShows how it happened, and, contrary to expectations, events like the cold weather in February could actually be more likely to happen due to global warming.

What happened in the Arctic doesn’t stop there

The Arctic is warming faster than any other region More than twice the world average..

This has caused major changes in the region’s climate, including melting sea ice and increased snow cover in Siberia in late autumn.

Because ice and snow provide an insulating layer and are highly reflective, their changes significantly change the amount of energy and moisture that travels between the Earth’s surface and the atmosphere. Because the atmosphere is sensitive to changes in energy and humidity, significant changes provide a “kick” to the atmosphere, resulting in upward-moving waves waving from that area.

These waves move upwards into the stratosphere, disrupting the stratosphere Stratospheric polar vortexAnother strong wind zone that orbits around the poles of the middle stratosphere, about 18 miles above. Correspondingly, the vortex weakens and stretches.

Two circulation patterns of stratospheric polar vortex: strong (left) and elongated (right). The blue curve shows the approximate edge of the vortex. It is displayed approximately 9.3 miles (15 kilometers) above the surface of the earth.University of Massachusetts Lowell Matthew Barlow

Vortices can change the behavior of waves because not only are vortices in the stratosphere changed by the waves, but they are also affected by the wind and temperature fields through which the waves pass, and the vortices help determine those winds and temperatures. I can do it. The difference between a vortex extension event and a larger vortex collapse is that upward-moving waves can reflect back to the surface and affect low-altitude weather patterns.

The schematic shows the wave activity reflected by the stretched stratospheric polar vortex.University of Massachusetts Lowell Matthew Barlow

When these downward-moving waves gather at low altitudes in North America, the jet stream has a southward slope, bringing colder air to the south than usual. Therefore, long-distance up-and-down movements of atmospheric waves, like ripples moving across ponds, can link the Arctic Circle to other regions.

Cause and effect testing

We have taken two different approaches to identify and investigate these relationships.

First, I used machine learning. This is a method in which a computer basically trains and groups similar events from historical data. Next, we analyzed the stretched vortex events and showed that in these cases there was a typical sequence of events. First the surface temperature of the Arctic changed, then the polar vortex of the stratosphere changed, and then cold waves occurred in North America and Asia. Waves moving vertically provide connectivity over a span of months. The changes in surface temperature observed in the Arctic are similar to those associated with melting sea ice and increased snow cover in Siberia due to Arctic climate change.

We then used a computer model of the atmosphere to evaluate the causes and effects and directly test how the atmosphere reacts to these changes in the Arctic Circle. It turns out that the model reproduces the series of events observed.

Machine learning analysis of observations and computer modeling experiments provide two independent pieces of evidence that support the path of influence. From surface Arctic climate change to stratospheric wind changes, and finally back to the cold waves of North America and parts of it. Asian.

The three globes show a timeline of change throughout the year.
The timeline shows the path from Arctic climate change to low temperatures in North America. The red and blue in the third panel show the difference from the average condition. Matthew Barlow / University of Massachusetts Lowell, CC BY-ND

Meaning of these results

Our research reinforces two important lessons of climate change. One is that climate change doesn’t have to happen in the backyard to have a big impact on you. Second, unexpected results can be very serious.

In this case, major changes in the Arctic will have widespread implications not only for regional concerns, but also for North America and parts of Asia. And those effects are not always what people expect. This result has another reason why we need to develop better strategies to manage both hot and cold extreme weather events while rapidly reducing greenhouse gas emissions that are causing global warming. It is embossed.

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