Meteorologists closely watch Pacific Ocean temperatures as a key indicator of whether the climate phenomenon known as El Niño is coming. But to also understand how strong it might be, bursts of wind from the western Pacific could provide more answers, according to a University of Maryland study.
A lack of such winds could be the reason why the El Niño that arrived in March, after nearly a year of anticipation, is weaker than climatologists expected.
The research, published in the journal Nature Geoscience, looked at 50 years of data on Pacific water surface temperatures and on bursts of winds that come from the western Pacific. While warmer-than-normal water temperatures are the hallmark of El Niño, the researchers found that the winds were present in strong El Niños, like in 1997, and absent in weaker ones, like this spring.
"These westerly wind bursts are intraseasonal — they're not weather, they're not climate, but somewhere in between," said Raghu Murtugudde, a professor of atmospheric and oceanic science at the University of Maryland, College Park, who is a co-author on the study. "We better learn to predict them if we are going to have skillful El Niño predictions."
The researchers suggest the wind bursts have an effect on ocean dynamics, helping to warm waters and spread the warm layer.
The warm waters help shift massive storm clouds over the ocean, disrupting global weather patterns and causing extreme precipitation in some parts of the world and drought in others.
Those changed patterns have little effect in Maryland. The region's geography between mountains and ocean, with the Chesapeake Bay in the middle, prevents dramatic climate fluctuations. El Niño is, however, associated with snowier-than-average winters here.