Bobbing in the swells of the eastern tropical Pacific Ocean sits an array of 55 moored buoys, which scientists have placed there since the mid 1980s to monitor the ocean and atmosphere for signs of El Niño and La Niña events. Such events, which are characterized by changes in water temperatures and air circulation, can wreak havoc on global weather patterns, and accurately anticipating them can save billions of dollars annually.
The Tropical Atmosphere Ocean Project, or TAO buoy array, was designed as an EKG test for the ocean — there to detect the first signs of impending trouble.
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But now the early warning system has gone silent, partially blinding scientists at the precise time that they think a new El Niño event — potentially a strong one — is stirring.

A TAO buoy seen next to a NOAA research ship, which was used for maintaining the buoy array across the Pacific Ocean.
Image: NOAA
So when scientists at the National Oceanic and Atmospheric Administration issued an El Niño Watch on Thursday morning, they did so after examining only fraction of the data they had become accustomed to using.
Due to budget cuts, bureaucratic reshuffling and bad luck, only about one-third of the buoys are now reporting on a daily basis, with the rest sending either no or partial data back to scientists. In order to predict El Niño events, scientists need data not just on conditions at the sea surface, but also in deeper waters. Since they are anchored in place, the TAO array has long been the way to get such observations, providing subsurface temperature readings throughout the upper 1,600 feet of water.
David Legler, who oversees climate observing systems for NOAA, told Mashable that forecasters are "heavily reliant" on the TAO data, although they have other things they look at, including information from other buoys that drift with ocean currents, satellite imagery and information sent back from passing ships.
According to Legler, the decline of the TAO array has its roots in NOAA’s retirement of the research ship Ka’Imimoana in 2012, after the vessel had reached the end of its design lifetime. That ship had been used for conducting annual maintenance on the TAO buoys, to the tune of about $10 million per year. In addition, the increasingly tight federal science budgets since that time have reduced NOAA’s ability to restore the buoys to their full functionality.
Michael McPhaden, a senior scientist at NOAA’s Pacific Marine Environmental Laboratory in Seattle and longtime proponent of the TAO array, told Mashable that no one knows exactly how detrimental the lost data will be for NOAA’s El Niño forecasts. “A big question on everyone’s mind is just how much of an impact this will have. We don’t know,” McPhaden said. “The presumption is the more data you have, the better off you are.”

Map showing the TAO buoys, with buoys reporting recent data colored in yellow and those without recent data in red.
Image: National Data Buoy Center
Gabriel Vecchi, a researcher at NOAA’s Geophysical Fluid Dynamics Laboratory in Princeton, N.J., said the ailing TAO array is likely to reduce El Niño forecast accuracy, and that this may create problems anticipating the impacts of an El Niño event. For example, El Niño events tend to suppress Atlantic hurricanes, and increase precipitation along the West Coast of the U.S. in wintertime, among other impacts.
“Essentially, I don't see how TAO being at 30% to 40% capacity right now can possibly help our predictions of ENSO,” Vecchi said in an email conversation, using the abbreviation for El Niño-Southern Oscillation, which is the broader climate cycle of which El Niño is one part. “Seasonal prediction is very challenging even in the best of worlds — and we don't get extra points for "degree of difficulty."
Vecchi, McPhaden, and others contacted for this article said the missing TAO data will be a setback for scientists’ overall understanding of how El Niño events unfold, and how climate change may be altering them.
Lisa Goddard, who directs the International Research Institute for Climate and Society at Columbia University, which teams up with NOAA to make El Niño and La Niña forecasts, told Mashable that TAO needs to be revived and maintained. “...We can gain a lot of insight to the forecasts by watching the development of the upper ocean below the surface,” she said.
“It is also critically important to have a long stable history from this observing system, not only to put a current event into proper context, but also to help us document and understand changes in the tropical Pacific on decadal timescales and even climate change. Moored buoys are so important to this because they do not drift away with the currents that diverge from the equator.”
“Maybe TAO needs to be refreshed or updated, but it should not be allowed to die,” Goddard said.
Fortunately, at a recent symposium at the Scripps Institution of Oceanography in La Jolla, Calif., NOAA officials pledged to work to restore TAO to its full functionality within the next year by relying on contract ships and money shifted from other accounts, McPhaden said. However, the restoration may come too late to do much good for forecasting the developing El Niño event, which is forecast to potentially take shape by later this summer, he said.