[OANNES Foro] The Madden-Julian Oscillation (MJO) disrupts weather worldwide, report finds

[Mario Cabrejos]

Warming of Indo-Pacific waters disrupting weather worldwide, report finds

by  <https://news.mongabay.com/by/ongabay-com/> Mongabay.com 

3 December 2019 

https://news.mongabay.com/2019/12/warming-of-indo-pacific-waters-disrupting-
weather-worldwide-report-finds/?utm_source=Mongabay+Email+Alerts&utm_campaig
n=c013f89ffa-mailchimp_climate_weekly&utm_medium=email&utm_term=0_e1ea8b5f35
-c013f89ffa-76256527

An expanse of warm water in the Indo-Pacific doubled in size between 1900
and 2018, adding an area the size of California every year. The culprit?
Rising carbon dioxide emissions, according to climate scientists, who write
in a recent  <https://www.nature.com/articles/s41586-019-1764-4> paper that
the warm water system is already disrupting weather patterns across the
world, from Asia to Africa and the Americas.

As the 25th Conference of Parties (COP) of the U.N. Framework Convention on
Climate Change gets underway in Madrid, the paper published in Nature draws
attention to the impact of warming oceans on global weather patterns. In
particular, the study examines the effect of this expanding swath of warm
water on the Madden-Julian Oscillation (MJO), a system of rain-bearing
clouds, winds and pressure fronts that traverses eastward over the tropics
along the equator.



An illustration from the Nature paper capturing the expansion of the warm
water pool. Image courtesy: Nature/ Roxy Mathew Koll

The importance of the MJO can be gauged from the fact that it regulates,
among other things, cyclone formation, the monsoon system, and El Niño
cycles. The MJO contributes to severe weather events the world over, but has
disparate effects in different places, playing a role both in the dry spell
gripping California and the Arctic polar vortices that cause frosty winters
in North America.

The authors of the Nature paper compared the size of the warm pool in the
period 1900-1980 to its size in 1981-2018 and noticed the dramatic
enlargement. They found that the swelling warm water pool skews the life
cycle of the MJO. “Rapid warming over the tropical oceans during 1981-2018
has warped the MJO life cycle, with its residence time decreasing over the
Indian Ocean by 3-4 days, and increasing over the Indo-Pacific Maritime
Continent by 5-6 days.”

The MJO usually originates over the Indian Ocean and travels eastwards over
the Indo-Pacific Maritime Continent towards the Pacific Ocean, where it
dissipates in the cooler waters of the eastern Pacific. The Indo-Pacific
Maritime Continent refers to the area sandwiched between the Indian and
Pacific Oceans spanning the archipelagos of Indonesia, Borneo, New Guinea,
the Philippines and the Malay Peninsula.

The system is made of two poles of activity, one associated with more
precipitation and the other with lower rainfall. It typically takes 30 to 60
days to pass from the Indian Ocean to the Pacific. Depending on how long it
lingers over a region, its impact can be felt on weather patterns. 

 
<https://news.mongabay.com/2019/12/warming-of-indo-pacific-waters-disrupting
-weather-worldwide-report-finds/Nature/%20Roxy%20Mathew%20Koll> 

An illustration from the Nature paper showing the impacts of the changes in
the life cycle of the MJO. Image courtesy: Nature/ Roxy Mathew Koll

The longer lingering time identified by the authors led to increased rain in
northern Australia, the western Pacific, the Amazon Basin, southwest Africa
and Southeast Asia, while at the same time bringing drier conditions to the
central Pacific, along the West and East coasts of the United States, north
India, East Africa, and the Yangtze Basin in China.

“Climate model simulations indicate that continued warming of the
Indo-Pacific Ocean is highly likely, which may further intensify these
changes in global rainfall patterns in the future,” Roxy Mathew Koll, at the
Indian Institute of Tropical Meteorology and first author of the study, said
in a statement. “This means that we need to enhance our ocean observational
arrays to monitor these changes accurately, and update our climate models to
skillfully predict the challenges presented by a warming world.”

The research work was a collaboration between scientists at India’s Ministry
of Earth Sciences, the U.S. National Oceanic and Atmospheric Administration
(NOAA), the University of Washington, and the University of Tokyo.

Citation:                                                         

Roxy, M. K., Dasgupta, P., McPhaden, M. J., Suematsu, T., Zhang, C., & Kim,
D. (2019). Twofold expansion of the Indo-Pacific warm pool warps the MJO
life cycle. Nature, 575(7784), 647-651. doi:
<https://doi.org/10.1038/s41586-019-1764-4> 10.1038/s41586-019-1764-4

 

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