Climate change makes summer weather stormier yet more stagnant

Climate
Credit: CC0 Public Domain

Climate change is shifting the energy in the atmosphere that fuels summertime weather, which may lead to stronger thunderstorms and more stagnant conditions for midlatitude regions of the Northern Hemisphere, including North America, Europe, and Asia, a new MIT study finds.

Scientists report that rising , particularly in the Arctic, are redistributing the energy in the atmosphere: More energy is available to fuel thunderstorms and other local, convective processes, while less energy is going toward summertime extratropical cyclones—larger, milder weather systems that circulate across thousands of kilometers. These systems are normally associated with winds and fronts that generate rain.

"Extratropical cyclones ventilate air and air pollution, so with weaker extratropical cyclones in the summer, you're looking at the potential for more poor air-quality days in urban areas," says study author Charles Gertler, a graduate student in MIT's Department of Earth, Atmospheric and Planetary Sciences (EAPS). "Moving beyond air quality in cities, you have the potential for more destructive thunderstorms and more stagnant days with perhaps longer-lasting heat waves."

Gertler and his co-author, Associate Professor Paul O'Gorman of EAPS, are publishing their results in the Proceedings of the National Academy of Sciences.

A shrinking gradient

In contrast to more violent tropical cyclones such as hurricanes, extratropical cyclones are large weather systems that occur poleward of the Earth's tropical zone. These storm systems generate rapid changes in temperature and humidity along fronts that sweep across large swaths of the United States. In the winter, extratropical cyclones can whip up into Nor'easters; in the summer, they can bring everything from general cloudiness and light showers to heavy gusts and thunderstorms.

Extratropical cyclones feed off the atmosphere's horizontal temperature gradient—the difference in between northern and southern latitudes. This temperature gradient and the moisture in the atmosphere produces a certain amount of energy in the atmosphere that can fuel weather events. The greater the gradient between, say, the Arctic and the equator, the stronger an extratropical is likely to be.

In recent decades, the Arctic has warmed faster than the rest of the Earth, in effect shrinking the atmosphere's horizontal temperature gradient. Gertler and O'Gorman wondered whether and how this has affected the energy available in the atmosphere for extratropical cyclones and other summertime weather phenomena.

They began by looking at a global reanalysis of recorded climate observations, known as the ERA-Interim Reanalysis, a project that has been collecting available satellite and weather balloon measurements of temperature and humidity around the world since the 1970s. From these measurements, the project produces a fine-grained global grid of estimated temperature and humidity, at various altitudes in the atmosphere.

From this grid of estimates, the team focused on the Northern Hemisphere, and regions between 20 and 80 degrees latitude. They took the average summertime temperature and humidity in these regions, between June, July, and August for each year from 1979 to 2017. They then fed each yearly summertime average of temperature and humidity into an algorithm, developed at MIT, that estimates the amount of energy that would be available in the atmosphere, given the corresponding temperature and humidity conditions.

"We can see how this energy goes up and down over the years, and we can also separate how much energy is available for convection, which would manifest itself as thunderstorms for example, versus larger-scale circulations like extratropical cyclones," O'Gorman says.

Seeing changes now

Since 1979, they found the energy available for large-scale extratropical cyclones has decreased by 6 percent, whereas the energy that could fuel smaller, more local thunderstorms has gone up by 13 percent.

Their results mirror some recent evidence in the Northern Hemisphere, suggesting that summer winds associated with have decreased with global warming. Observations from Europe and Asia have also shown a strengthening of convective rainfall, such as from thunderstorms.

"Researchers are finding these trends in winds and rainfall that are probably related to climate change," Gertler says. "But this is the first time anyone has robustly connected the average change in the atmosphere, to these subdaily timescale events. So we're presenting a unified framework that connects climate change to this changing weather that we're seeing."

The researchers' results estimate the average impact of global warming on summertime energy of the atmosphere over the Northern Hemisphere. Going forward, they hope to be able to resolve this further, to see how may affect weather in more specific regions of the world.

"We'd like to work out what's happening to the available energy in the atmosphere, and put the trends on a map to see if it's, say, going up in North America, versus Asia and oceanic regions," O'Gorman says. "That's something that needs to be studied more."


Explore further

NASA catches Tropical Cyclone Gelena's post-tropical transition

More information: Charles G. Gertler el al., "Changing available energy for extratropical cyclones and associated convection in Northern Hemisphere summer," PNAS (2019). www.pnas.org/cgi/doi/10.1073/pnas.1812312116
Citation: Climate change makes summer weather stormier yet more stagnant (2019, February 18) retrieved 19 July 2019 from https://phys.org/news/2019-02-climate-summer-weather-stormier-stagnant.html
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User comments

Feb 18, 2019
Powerful recurrent rainstorms occurring in low-lying areas anywhere in the world with accompanying flooding, drownings, downed power lines and trees, possible tornados, broken glass store-fronts, stalled vehicles, and snakes in the water - can be quite worrisome.
Are these something new?
Whatever did ancient humans DO when flooding, drownings, possible tornados, and snakes in the water happen even occasionally? Did they call their Congressmen or MP or local tribal leader to come over to assess the problem and offer up some prayers and sacrifice a few he-goats to get someone to fix the problem(s)?

No. They gathered up their food, animal skins, their babies and headed for their favorite cave in the hills. If they found a bear inside - they killed it and ate it. They built campfires, cooked their food and told stories and sang songs - then they went to sleep with the storms raging outside.
A hardy lot they were. And their descendants have turned into ChickenLittles. (Sigh)

Feb 18, 2019
isn't this mixing weather and climate ?

Feb 18, 2019
"Whatever did ancient humans DO when flooding, drownings, possible tornados, and snakes in the water happen even occasionally?

They gathered up their food, animal skins, their babies and headed for their favorite cave in the hills" - Egg

Feel free to run to your cave in the hills ignorant Egg Boy.


Feb 19, 2019
There has been no warming since 1998.

Feb 19, 2019
The world is warming. This is a blessing. Earth was headed for snowball earth prior to human intervention of increasing carbon dioxide.

Feb 19, 2019
Thorium Boy
There has been no warming since 1998

grandpa
The world is warming. This is a blessing
This comment is an experiment. Bart thinks deniers will engage in polite debate.

Thorium Boy, grandpa - you are both wrong. The earth is warming - https://en.wikipe...ASA).svg and it is not a blessing. - https://climate.n...effects/

Any one up for some polite debate about the facts I was willing to support with actual links?

Feb 19, 2019
"Whatever did ancient humans DO when flooding, drownings, possible tornados, and snakes in the water happen even occ...?

They gathered up their food, animal skins, their babies and headed for their favorite cave in the hills" - Egg

Feel free to run to your cave in the hills ignorant Egg Boy.

says Vendicar aka Scott Nudds

Do you know of a cave that I could use in the event of an emergency? Most likely, I would find you in there already. LOL
You miss the whole point of what I said. Modern humans are too soft in the head to prepare for such eventualities where their homes and/or cities could be damaged or destroyed by natural incidents/causes. And so they look to their politicians/tribal leaders to take care of them instead of having taken care themselves to plan ahead so that they won't be taken by surprise.
In the old days, caves in the hills were good as a shelter from the rain for hunters, even temporary. Now, the only shelters are government recommended

Feb 19, 2019
Thorium Boy
There has been no warming since 1998

grandpa
The world is warming. This is a blessing
This comment is an experiment. Bart thinks deniers will engage in polite debate.

Thorium Boy, grandpa - you are both wrong. The earth is warming - https://en.wikipe...ASA).svg

Any one up for some polite debate about the facts I was willing to support with actual links?

says green o

No matter how many links you put up, the fact still remains that AGW is the primary Blame Game that will eventually enable the Elites of the Globalisation of Earth to come into absolute power over all nations and individuals. AGW is but one of the methods used to entice the gullible such as yourself to take down civilisation as it is now, for the purpose of removing the powerful economic/commerce/industrial blocks from the control of the USA and other western nations.

Feb 19, 2019
Eggo - I said polite debate about the FACTS. You made a massive allegation -
AGW is but one of the methods used to entice the gullible such as yourself to take down civilisation as it is now, for the purpose of removing the powerful economic/commerce/industrial blocks from the control of the USA and other western nations
But did not provide one bit of support. Alleging a massive conspiracy to take over the world - is not debating the facts - surely you understand that.

Feb 19, 2019
green, you have to realize...
seu is an active denierbot agitpropping for the Global Fascist Axis .
seu is a quisling for the russians & a copperhead for the saudis.

In the delusion that any of seu's worshiped puppetmasters would allow such vermin to sully the pristine corridors of their bunkers. What a gullible little lickspittle sycophant he/she/it is for tyranny.

Feb 19, 2019
yes summer weather is getting stormy !!

in Tasmania the first snow ! , welcome to global cooling

https://www.abc.n...cszqrGCg


Feb 19, 2019
We've had quite warm above average temperatures and not very much rainfall, but it's not that unusual for Tasmania to receive a significant cold front at any time of the year that can bring snow


Troll on snoose - I am sure you think you are engaging in very polite and sophisticated dialogue about the finer points of science.

Feb 19, 2019
tasmania 2017 HOT HOT HOT

https://www.exami...-summer/

Feb 19, 2019
From troll snoose' own article (the first one.)
We've had quite warm above average temperatures and not very much rainfall, but it's not that unusual for Tasmania to receive a significant cold front at any time of the year that can bring snow

Feb 19, 2019
but its the hottest ever ! , snow is a thing of the past they said

Feb 20, 2019
From troll snoose' own article (the first one.)
We've had quite warm above average temperatures and not very much rainfall, but it's not that unusual for Tasmania to receive a significant cold front at any time of the year that can bring snow


"Tasmania starts summer with 'heavy" snow falls"

Feb 20, 2019
Tasmania starts summer with 'heavy" snow falls
Which is normal (according to Snoose' article) - so you have no point.

Feb 20, 2019
Uhh, did I miss something?
Was there a calendar reform of which I wasn't inform?
I thought South Hemisphere experience Winter during the same months of the North Hemisphere's Summer?
Hawaii Snow, Heavy snow on the mountains.
Whhaaat!?!
Last I heard, it was unprecedented in recorded history.

That is a consequence of Anthropospecific Augmentation to Climate Change.

The denierbots bleat their dismay but they were not programmed with info about how a refrigerator works.
or "Why" the "How" of heat exchange.

Climate Change means the weather you will, if not already experiencing?
Will violently veer from whatever clime you are use too.
In the very worst way, at the very worst time, for you.

Speaking of calendar reform?
I wold encourage a switch back to thirteen Zodiacal months. Putting Ophiuchus back on the map, so to speak.
13 months, each of 4 weeks/28 days.

Think of the laughs pissing off astrologers & other stuporstitions! The jeebus cult will shit a brick,

Feb 20, 2019
Science_Evasion_Unit is back to the global conspiracy pablum again.

Feb 20, 2019
Science_Evasion_Unit is back to the global conspiracy pablum again.


Yep. The old Socialist conspiracy that ultimately leads to communism theory.
Well heck, it happened in Russia in 1917 - and it can happen here in the States - with so many millennial whooping and hollering for it. They think it's swell.
The young are always ALWAYS in the forefront for Collectivism. Just look at rrwillisj - just hankering for a collectivist Socialist society where everything will be free FREE FREE.
Ain't that right, williejoe?

Feb 20, 2019
When the nukes go off over New York, San Francisco, LA, Moscow, St Petersburg, London, Paris, Berlin, Bonn, Munich, and Rome, you will reap what you have sown. Luckily, I will be dead by then so it's your world, and denial isn't going to be a very popular stance. We found out about it in the 1970s. You denied and lied about it until the nukes went off.

WTF do you think they're gonna do? Just die? They got nuclear weapons. This is duhhh umm.

Now who's stupid?

Feb 20, 2019
but its the hottest ever ! , snow is a thing of the past they said
says snooiebaum

Don't you understand yet that the weather and climates are changing because WE are DENIERS of AGW and climate change. It's all because of US, and that is why all these AGW aficionados like green onions, Howhot3, troll bane, rrwillisj, and de rest of all dem bamboozled swallowers want to get us and string us up on the highest tree, cuz WE are doing it. WE are causing the snow to fall in Tasmania while WE drive our cars full of fossil fuels.
And Senator Ocasio-Cortez wants to get rid of farting cows. Well, the Democrats do an AWFUL LOT of farting too. Maybe she should get rid of them first. Aye?
ROFLOL

Feb 20, 2019
Coal is the problem, and China, Pakistan, and India are building more coal plants. And they all have nuclear weapons.

I should have added Christchurch and Adelaide to the list.

Feb 20, 2019
Eggo - I said polite debate about the FACTS. You made a massive allegation -
AGW is but one of the methods used to entice the gullible such as yourself to take down civilisation as it is now, for the purpose of removing the powerful economic/commerce/industrial blocks from the control of the USA and other western nations
But did not provide one bit of support. Alleging a massive conspiracy to take over the world - is not debating the facts - surely you understand that.
says green onions

Um let's see - provide one bit of support he says -
OK, how about Democrat Party Senator Bernie Sanders, Socialist Extraordinaire - who is now a possible candidate for President of the USA in the 2020 election.
Senator Alexandria Ocasio-Cortez, Dem Party Socialist from New York - who wants to get rid air travel, the US military, cow farts, and has recently lost 27 BILLION USD that would have been paid to workers in New York City by Amazon, because the Socialist dummy thought

Feb 20, 2019
that the State of New York was going to pay Amazon 5 Billion USD to set up their business in Long Island City, NY, She misunderstood in her ignorance what the governor had said, and so, Amazon isn't building in NY now, and all of those thousands of unemployed that would have been paid that 27 BILLION in wages now have nothing. ROFLOL

Feb 20, 2019
You're blathering about Western politics while India, Iran, Pakistan, Afghanistan, Russia, North Korea, China, and others are developing strategic ballistic nuclear weapons delivery platforms?

Are you stoned or stupid?

Feb 20, 2019
Umm George Soros is a Globalist
Angela Merkel seems to be a Globalist
All those who want "open borders" are Globalists

Feb 20, 2019
You're blathering about Western politics while India, Iran, Pakistan, Afghanistan, Russia, North Korea, China, and others are developing strategic ballistic nuclear weapons delivery platforms?

Are you stoned or stupid?
says Da Schithead

So why don't YOU get your arse over to those countries and tell them how you feel about what they're doing. Why complain in this phorum? What do you think WE can do about it, eh?
And don't worry, you won't feel a thing when they drop their nuclear bombs on your house.

Feb 21, 2019
OK, how about Democrat Party Senator Bernie Sanders, Socialist Extraordinaire
So Bernie is a democratic socialist (his own words) - who wants to run for President. That proves a global conspiracy to take down civilization? Maybe you should go back and consult with your friend Xenu. Get some lessons in critical thinking.

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