Summit County Citizens Voice

A NOAA graph shows how cyclical pulses of atmospheric energy from the Indian Ocean influence the formation of the Pineapple Express weather pattern that can slam the West Coast with intense precipitation.

Pulses of energy from the Madden-Julian oscillation in the Indian Ocean thought to influence weather worldwide

By Summit Voice

SUMMIT COUNTY — A team of international researchers is heading to the Indian Ocean to learn more about the genesis of the Madden-Julian oscillation, a cyclical climate phenomenon believed to be the greatest driver of atmospheric variability in the one- to three-month time frame, linking weather and climate.

The pulses of atmospheric energy that move around the globe from the Indian Ocean are believed to be linked with the famed Pineapple Express weather events that bring tremendous amounts of precipitation to the western U.S.. They also  influence the formation of hurricanes, and even the intensity of Colorado’s summer monsoon.

Understanding the origins of the oscillation could help forecasters pinpoint when major winter storms will hit the U.S.
Using aircraft, ships, moorings, radars, numerical models and other tools the six-month mission will study how tropical weather brews in the region and then moves eastward along the equator, with reverberating effects around the globe.

The disturbance originates in the equatorial Indian Ocean about every 30 to 90 days. It’s part of the Asian and Australian monsoons and can enhance hurricane activity in the northeast Pacific and Gulf of Mexico, trigger torrential rainfall along the west coast of North America and affect the onset of El Niño.

Scientists believe that the Madden-Julian is the world’s greatest source of atmospheric variability in the one- to three-month time frame.

“The Madden-Julian Oscillation has a huge impact all over the globe,” said Chidong Zhang of the University of Miami, the research project’s chief scientist. “It connects weather and climate, and it is important to forecasting.”

The research team includes scientists from the Boulder-based National Center for Atmospheric Research.
“The MJO drives weather in both hemispheres even though it sits along the equator,” said NCAR’s Jim Moore, director of the DYNAMO project office. “Its origins have never been measured in such a systematic fashion before.”

The main observation sites will be based in the Maldives, Diego Garcia and Manus Island, as well as aboard research ships and aircraft in the Indian Ocean. The major radar array and land-based observation “Super Site” will be located on Addu Atoll.

The MJO plays a key role in driving tropical weather and climate variations during all seasons of the year. It also interacts with other atmospheric patterns, such as the El Niño/Southern Oscillation and the North Atlantic Oscillation, that can shape weather and climate patterns across much of the globe.

Scientists need to better understand the MJO, both to improve long-range weather forecasts and seasonal outlooks worldwide, and perhaps make the leap to longer-term forecasts of climate that may extend years into the future.

In winter, for example, the onset of an MJO can set off atmospheric waves that travel across the globe and, about 10 days later, influence the location and severity of major storms on the west coast of North America, some of which cause significant flooding.

“If you can find out how an MJO event starts, you may get a couple of weeks’ warning about wintertime storms in the United States,” says NCAR scientist Mitchell Moncrieff, a member of the DYNAMO Science Steering Committee.

At present, the computer models that scientists use to study global weather and climate fail to capture the oscillation very well. The information from the field campaign can lead to significant improvements in the models.

In addition to measuring the sky, the researchers also will turn their attention to the sea. The physical properties of the ocean, such as temperature and salinity, are as important to the MJO as are the properties of the atmosphere. A collection of ocean sensors, deployed from ships and moorings in the open ocean, will collect data on ocean-atmosphere interactions.

Filed under: climate and weather, El Niño, La Niña, Summit County snow and weather Tagged: | Indian Ocean, Madden–Julian oscillation, National Center for Atmospheric Research, pineapple express