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March 4, 2002 Volume 26, Issue 28 |
The cause of this winter's roller coaster Southern weather-balmy temperatures one day followed by below-freezing the next-has its origin on the other side of the world.
According to Mississippi State climatologist Michael E. Brown, a weather disturbance in the tropics of the Indian Ocean is the starting point for the cycles of unseasonably warm temperatures. Known as the Madden Julian Oscillation, the atmospheric condition first was identified in the mid-1970s.
"Only in the last seven or eight years have scientists begun to link the Madden Julian Oscillation with tropical storms," explains the associate professor of geosciences.
Occurring every 30-60 days, MJO creates a region of thunderstorms as it spreads eastward across the Pacific Ocean. A cycle of varying weather conditions results.
"It creates tremendous clouds, which shade the ocean surface and prevent heat over the oceans," Brown says.
Wind patterns in the MJO also have been linked to greater hurricane and tropical storm activity, he adds.
The phenomenon appears to be the strongest December-March before tapering off in the summer.
"This has been a very strong season for the Madden Julian Oscillation and the weather patterns will follow it," Brown observes. "We will have 30 days of cool weather and 30 days of warm weather."
Luckily, Brown said, the weather should be returning to a more normal seasonal pattern. "Our temperatures should now be in the lower 40s rather than the lower 80s that we've experienced in January."