Reliable tropical weather pattern to change in a warming climate

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 anthropogenic global warming. Maloney and co-authors used data from six existing climate models to synthesize current views of such changes projected for the years 2080-2100.

Their analysis reveals that while the Madden-Julian Oscillation's precipitation variations are likely to increase in intensity under a warmer climate, 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 oscillation's wind signal may thus diminish meteorologists' ability to predict extreme weather events. 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.

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

Research paper

Related Links
Colorado State University
Earth Observation News - Suppiliers, Technology and Application

Tweet

Thanks for being there;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Monthly Supporter
$5+ Billed Monthly

paypal only

SpaceDaily Contributor
$5 Billed Once

credit card or paypal

Researchers rise to challenge of predicting hail, tornadoes three weeks in advance
Fort Collins CO (SPX) Dec 03, 2018
People living in Kansas, Nebraska and other states in the Plains are no strangers to tornadoes and hail storms - among the most costly and dangerous severe weather threats in the United States. Meteorologists and computer models do a good job forecasting severe thunderstorm activity up to a week in advance. Scientists can also read long-term, seasonal signals of severe weather months in advance.But there's a middle ground - a prediction lead time of about 2 to 5 weeks - that's sorely lacking in cu ... read more