Pacific Ocean Currents Are Accelerating, and It Could Change Global Climate As We Know It

 

Pacific Ocean Currents Are Accelerating, and It Could Change Global Climate As We Know It


A crucial ocean layer essential to the dynamics of the El Niño–Southern Oscillation (ENSO).

A recent study published in the Journal of Geophysical Research: Oceans reports a marked acceleration in upper-ocean circulation within the equatorial Pacific over the last three decades.

The primary driver of this acceleration is intensified atmospheric winds, resulting in stronger and shallower ocean currents. These changes may influence regional and global climate patterns, potentially affecting the frequency and intensity of El Niño and La Niña events. The study offers a spatial perspective on these long-term trends based on observational data, extending insights by at least another decade beyond previous research.

West East Near Surface Current Trend Between 1993–2022
West-east near-surface current trend between 1993-2022. Blue colors show increased westward currents; red colors show increased eastward currents. The largest trends are observed in the central tropical Pacific Ocean (black box). Current velocity data from three equatorial moored buoys (yellow diamonds) provide a subsurface view on long-term upper-ocean current velocity trends. Credit: Graphic figure: Franz Philip Tuchen Satellite image background NOAA NESDIS

The research team, led by Franz Philip Tuchen, a postdoctoral scientist at the University of Miami Rosenstiel School’s NOAA Cooperative Institute for Marine and Atmospheric Studies (CIMAS), in collaboration with NOAA’s Atlantic Oceanographic and Meteorological Laboratory (AOML), synthesized thirty years of long-term ocean and atmosphere observations from satellites, mooring buoys, and ocean surface drifters.

By integrating the reanalysis of wind data and satellite altimetry into a high-resolution, gridded time series of near-surface ocean currents, this study presents a new and comprehensive view to date of the changes in the Pacific upper-ocean circulation.

Findings: Accelerated Currents and Potential Climate Impacts

The research findings indicate that stronger winds across the equatorial Pacific have caused a notable acceleration of westward near-surface currents by approximately 20 percent in the central equatorial Pacific. Poleward currents north and south of the equator have also accelerated, with increases of 60 percent and 20 percent, respectively.

The equatorial thermocline—a critical ocean layer for El Niño–Southern Oscillation (ENSO) dynamics—has steepened significantly,” said Tuchen. “This steepening trend could reduce ENSO amplitude in the eastern Pacific and favor more frequent central Pacific El Niño events, potentially altering regional and global climate patterns associated with ENSO.”

The researchers indicate the study offers a benchmark for climate models, which have had limited success to accurately represent Pacific circulation and sea surface temperature trends. The researchers suggest the findings could help improve the predictability of ENSO events and related weather patterns, especially for regions like the United States, which experience significant climate variability from ENSO-driven changes.

Reference: “Strengthening of the Equatorial Pacific Upper-Ocean Circulation Over the Past Three Decades” by Franz Philip Tuchen, Renellys C. Perez, Gregory R. Foltz, Michael J. McPhaden and Rick Lumpkin, 31 October 2024, Journal of Geophysical Research: Oceans.
DOI: 10.1029/2024JC021343

Funding for this study was provided by NOAA’s Global Ocean Monitoring and Observing (GOMO) programs, including the Global Tropical Moored Buoy Array (GTMBA), the Global Drifter Program (GDP), and the Tropical Atmosphere Ocean (TAO) program.

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