Reliable tropical weather pattern to change in a warming climate

December 28, 2018 by Anne Manning, Colorado State University
Current climate is represented in (a), and a warmer climate in (b). As the climate warms, the mean vertical gradient in water vapor (blue) increases. Tropospheric temperature (orange shading) will also increase more than the lower atmosphere. Credit: Eric Maloney/Colorado State University

Every month or two, a massive pulse of clouds, rainfall and wind moves eastward around the Earth near the equator, providing the tropics their famous thunderstorms.

This band of recurring weather, first described by scientists in 1971, is called the Madden-Julian Oscillation. It has profound effects on weather in distant places, including the United States. Atmospheric scientists have long studied how the Madden-Julian Oscillation modulates extreme weather events across the globe, from hurricanes to floods to droughts.

As human activities cause the Earth's temperature to increase, reliable, well-studied weather patterns like the Madden-Julian Oscillation will change too, say researchers at Colorado State University.

Eric Maloney, professor in the Department of Atmospheric Science, has led a new study published in Nature Climate Change that attributes future changes in the behavior of the Madden-Julian Oscillation to . Maloney and co-authors used data from six existing climate models to synthesize current views of such changes projected for the years 2080-2100.

Separating precipitation, wind

Their analysis reveals that while the Madden-Julian Oscillation's precipitation variations are likely to increase in intensity under a , wind variations are likely to increase at a slower rate, or even decrease. That's in contrast to the conventional wisdom of a warming climate producing a more intense Madden-Julian Oscillation, and thus an across-the-board increase in extreme weather.

"In just looking at precipitation changes, the Madden-Julian Oscillation is supposed to increase in strength in a future climate," Maloney said. "But one of the interesting things from our study is that we don't think this can be generalized to wind as well."

Atmospheric science relies on weather patterns like the Madden-Julian Oscillation to inform weather prediction in other areas of Earth. For example, atmospheric rivers, which are plumes of high atmospheric water vapor that can cause severe flooding on the U.S. west coast, are strongly modulated by certain phases of the Madden-Julian Oscillation.

According to Maloney's work, the Madden-Julian Oscillation's impact on remote areas may gradually decrease. Degradation in the 's wind signal may thus diminish meteorologists' ability to predict . In particular, preferential warming of the upper troposphere in a future, warmer climate is expected to reduce the strength of the Madden-Julian Oscillation circulation.

Next steps

Maloney and colleagues hope to continue studying the Madden-Julian Oscillation using a broader set of to be used in the next Intergovernmental Panel on Climate Change assessment.

Co-authors of the Nature Climate Change study are Ángel Adames of the University of Michigan and Hien Bui, a CSU postdoctoral researcher.

Explore further: Researchers rise to challenge of predicting hail, tornadoes three weeks in advance

More information: Eric D. Maloney et al, Madden–Julian oscillation changes under anthropogenic warming, Nature Climate Change (2018). DOI: 10.1038/s41558-018-0331-6

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10 comments

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Shootist
1 / 5 (9) Dec 28, 2018
Warmer weather is better than cooler weather for humans and other growing things. See Holocene Climate Optimum, Roman Climate Optimum and the Medieval Climate Optimum.

hint: There's a reason they're called "optimums".
Da Schneib
4.4 / 5 (7) Dec 28, 2018
The PETM isn't called an "optimum."

Maybe you forgot.
mabrams
1.7 / 5 (6) Dec 28, 2018
How did the six climate models used in this study do in actually predicting anything, like temperature or anything else. If any of the models were accurate and had predicted anything correctly why bother with the other five? So take 6 inaccurate models and use them to predict a new horrible outcome unless political power and wealth are ceded to one world scare mongering politicians. But garbage in then garbage out, especially when the garbage is processed by credentialed garbage men in white lab coats pretending to be scientists.
Bert_Halls
3.9 / 5 (7) Dec 28, 2018
@shootist

Cut your wrists so your blood pressure will stay at a nice, low "optimal."
philstacy9
1.7 / 5 (6) Dec 29, 2018
Climate warming is fake data and models which are only useful in determining who is honest.
https://www.washi...te-disa/
antigoracle
2.3 / 5 (3) Dec 29, 2018
The PETM isn't called an "optimum."

Maybe you forgot.

Da Snot, the "meat" loving, knob gobbling, jackass brays again. He's obviously, still angry that his boyfriend hasn't found that "sweet spot" in his rectum.
Hey jackass, instead of having your boyfriend rattle the shite between your ears, perhaps he can explain Shootist's comment to you. Those periods were OPTIMUM for humans.... How many humans were there, during the PETM?
Keep braying at the heretics, you jackass, that's how you'll save the world.
rrwillsj
5 / 5 (2) Dec 29, 2018
The denialists suffer from being too stupid to understand the concept of "measurement".
No wonder they keep flunking sixth grade!

Okay children, now pay attention."
"Sigh... Some one poke "Shotfoot" & wake him up."

"Okay, now that we are all present? These two rulers I am holding are used to measure in three dimensions. They both measure the same thing, such as this desk,"

Checking that Shotfoot & the other victims of comicnooks & videogames. Were all sitting up, even if not conscious. The teacher continues.
"These measuring tools differ, in that one measures inches & feet. The other measures in metric. The reason for learning the metric system is that for scientific uses, the metric system is considered more accurate."

Noticing that Shotfoot had his head down on his desk, the teacher approached & slammed the rulers against the front of the dunce's desk.

"For measuring temperature we us Fahrenheit & Centigrade.& Kelvin. Heat energy is not temperature."
HeloMenelo
3 / 5 (2) Dec 31, 2018
lol @ rrwillsj

(you should release them from class, to them it's prison)

They thrive up in the trees.

Antisciencegorilla and shoot the potty miss really having a racket swinging the branches, quite hilarious as usual, those branches cracking like never before as the sound of barking and chatter passes by.
rrwillsj
not rated yet Dec 31, 2018
HM, U love the accuracy of your imagery!
philstacy9
1 / 5 (1) Jan 02, 2019

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