NOAA said on Sept. 10 that the developing El Niño Southern Oscillation winter weather pattern has a 75% chance of becoming a historic event stronger than previous El Niño events dating back to 1950. The forecast came as four Saildrone Explorers began gathering data in the equatorial Pacific. The question now is how fast the event intensifies as those measurements fill a long-standing gap.
NOAA and Saildrone
NOAA launched the four autonomous Saildrone Explorers off Honolulu to study conditions in the equatorial Pacific. Each Saildrone Explorer is a 23-foot uncrewed surface vehicle with 15 meteorological and oceanographic sensors that measure temperatures, salinity, carbon dioxide, and ocean currents. NOAA said sea surface temperatures in the El Niño region were hotter than they had ever been on record for that time of year.
The mission is built around a simple problem: the El Niño region changes quickly, but ships and other observing systems do not always sample it where the action is happening. Dongxiao Zhang said the uncrewed surface vehicles can “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 proce”.
Michael McPhaden and 1982
The project includes scientists at the Pacific Marine Environmental Laboratory and the University of Washington, working through the Cooperative Institute for Climate, Ocean & Ecosystem Studies. Michael McPhaden, a researcher at the University of Washington, said his first big El Niño arrived in 1982. He said, “We had no observing system, we didn't see it coming,” and “We had no forecast models. We didn't actually realize it was happening until it was nearly at its peak.”
McPhaden described that episode as “shock and embarrassment” for the international science community. Over a decade starting in 1984, the science program built an array of ocean observing platforms and satellites. Today that array has been redesigned and is providing a stream of data as this El Niño develops.
Hurricane Lowell and five months
The launch was temporarily disrupted as Hurricane Lowell bore down on the Hawaiian Islands, and the drones were steered out of harm’s way before continuing on their journey. When the Saildrones reach the El Niño region, they will spend the next five months collecting measurements.
Emily Becker, a research associate at the University of Miami’s Rosenstiel School of Marine, Atmospheric, and Earth Science, said, “It’s an opportunity to learn more about what El Niño is going to look like in a warmer climate.” Meghan Cronin, who leads the Ocean Climate Stations group at NOAA’s Pacific Marine Environmental Laboratory, said the results should give scientists “a lot more information than we could see in any other way” about conditions in the El Niño region.
Cronin said scientists hope to make progress on forecasts of events that affect water resources, energy resources, agriculture, and lives. NOAA’s latest forecast gives them a moving target, and the new measurements are meant to narrow it before the event peaks.
