As a potentially historic El Niño develops along the equator, scientists see opportunities to explore the unanswered questions about these events that disrupt global weather.
“It’s an opportunity to learn more about what El Niño is going to look like in a warmer climate,” said Emily Becker, research associate at the University of Miami’s Rosenstiel School of Marine, Atmospheric, and Earth Science.
A Sept. 10 update from the National Oceanic and Atmospheric Administration predicted a 75% chance that this El Niño could be "a historic event that would exceed the strength of previous El Niño events dating back to 1950."
Off Honolulu, NOAA recently launched a fleet of four autonomous Saildrone Explorers on a mission to the equatorial Pacific to study
conditions in the region. Their mission was temporarily disrupted as Hurricane Lowell bore down on the Hawaiian Islands, and the drones had to be steered out of harm’s way before continuing on their journey.
Once the Saildrones, sometimes called robot surfboards, reach the El Niño region, where NOAA data shows sea surface temperatures are hotter than they’ve ever been on record for this time of year, the drones will spend the next five months collecting measurements.
The results are expected to give scientists “a lot more information than we could see in any other way” about conditions in the El Niño region, said Meghan Cronin, a research oceanographer who leads the Ocean Climate Stations group at NOAA's Pacific Marine Environmental Laboratory.
A history of El Niño observations
Michael McPhaden, a researcher at the University of Washington, has studied El Niño for nearly 50 years. He retired as a senior scientist with NOAA in June but isn't stepping away from his work yet, given the developing El Niño.
His first big El Niño arrived in 1982. "We had no observing system, we didn't see it coming," he said. "We had no forecast models. We didn't actually realize it was happening until it was nearly at its peak."
At the time, the international science community was planning a 10-year program to study El Niño, and the surprise event was something of a "shock and embarrassment," he said.
Over a decade starting in 1984, the program built an array of ocean observing platforms and satellites. Today, Cronin said, that array has been redesigned and is providing a stream of data as this El Niño develops.
It’s exciting work, she said. “We’ll really hopefully make some big progress on being able to improve our forecast of these events that have such a big impact on water resources, energy resources, agriculture, and our lives.”
What is a Saildrone?
The 23-foot long Saildrone Explorers are uncrewed surface vehicles. Similar versions have been used for studies in the Atlantic Ocean's hurricane basin.
Each vessel is equipped with 15 different meteorological and oceanographic sensors that constantly collect data, said Cristina Castillo, senior program manager of ocean science for the company, Saildrone. The sensors measure conditions such as temperatures, salinity, carbon dioxide and ocean currents.
The project includes scientists at NOAA's Pacific Marine Environmental Laboratory and the University of Washington who collaborate through the joint Cooperative Institute for Climate, Ocean & Ecosystem Studies.
NOAA's lead investigator for the project, Dongxiao Zhang, said the uncrewed surface vehicles “open a new era of ocean observation by targeting areas where data are most needed to improve our understanding and forecasts of high-impact, rapidly developing air-sea processes like this El Niño, that will have profound effects around the world.”
The wind-propelled and solar-powered drones can be moved to locations where scientists want to collect more data, Castillo said. That's important because what's happening thousands of miles away "really controls global weather patterns and whether we face extreme storms, flooding and disruptions to fisheries."
What do scientists hope to learn?
Over the decades since McPhaden started, scientists have learned far more about large-scale atmospheric and ocean processes. That’s helped them predict when an El Niño or La Niña event will occur and dramatically improved forecasts for tropical storms and hurricanes around the world. Now they want finer details.
An El Niño climate pattern might be compared to a bonfire, with ocean heat as the dry wood, he said. Scientists are trying to learn more about the short-term weather disturbances believed to provide the spark that starts the fire. The spark doesn't always come from the same place, he said, and there are multiple reasons why the trade winds relax or shift to start the El Niño/La Niña events.
This year, for example, it appears a pair of twin cyclones on either side of the equator in the Western Pacific in April helped ignite El Niño by producing very strong winds toward the east, McPhaden said. Other factors such as waves of heat energy in warm water, known as Kelvin waves, and short-term bursts of tropical weather disturbances in a pattern called the Madden-Julien Oscillation also play a role.
Why is it important to understand El Niño?
Ben Kirtman, dean of the University of Miami’s Rosenstiel School, said we don’t yet have answers to the “really important question” of how El Niño interacts with the evolving problem of climate change.
El Niño and La Niña events are nature’s way of balancing out the global atmosphere, said Jhordanne Jones, an assistant professor in the Department of Meteorology and Atmospheric Science at Penn State.
She looks at the global system as one harmony and one melody, with all these signals within.
“With climate change, the system is hearing a different melody happening, a more irregular type of melody," she said, and scientists need to understand how the natural variability and related weather extremes might be changing.
Dinah Voyles Pulver, a national correspondent for USA TODAY, covers violent weather, climate and the environment, among other news. Reach her at dpulver@usatoday.com.
This article originally appeared on USA TODAY: An unprecedented El Niño sends scientists scrambling for answers
