A recent study published on October 31, 2024, in the Journal of Geophysical Research: Oceans has shown a notable increase in the upper-ocean circulation of the equatorial Pacific over the last three decades. This boost is mainly caused by stronger atmospheric winds, resulting in ocean currents that are not only more vigorous but also shallower. These changes could affect climate patterns both regionally and globally, including how often and how intensely El Niño and La Niña events occur.The past three decades have seen a notable increase in ocean temperatures, mainly due to heightened atmospheric winds. These winds have caused stronger and shallower ocean currents, which may affect both local and global climate trends. This includes changes in the frequency and severity of El Niño and La Niña phenomena. The research offers a comprehensive view of these long-term changes based on observations, adding over ten years’ worth of data compared to earlier studies.
The study was conducted by a team led by Franz Philip Tuchen, who is a postdoctoral researcher at the University of Miami’s Rosenstiel School within the NOAA Cooperative Institute for Marine and Atmospheric Studies.IMAS, in partnership with NOAA’s Atlantic Oceanographic and Meteorological Laboratory (AOML), has compiled three decades’ worth of ocean and atmosphere data from satellites, mooring buoys, and surface drifters. By incorporating the analysis of wind data along with satellite altimetry into a detailed time series of near-surface ocean currents, this study offers an updated and thorough perspective on the changes occurring in the upper circulation of the Pacific Ocean.
The results reveal that increased wind strength over the equatorial Pacific has led to a significant speed-up of westward near-surface currents by approximately
Current observations show that ocean currents in the central equatorial Pacific have increased by nearly 20 percent. Additionally, poleward currents both north and south of the equator have experienced notable acceleration, with increases recorded at 60 percent and 20 percent, respectively.
“The equatorial thermocline, which plays a crucial role in the dynamics of the El Niño-Southern Oscillation (ENSO), has become significantly steeper,” Tuchen expressed. “This trend towards steepening may diminish the amplitude of ENSO in the eastern Pacific while promoting more frequent central Pacific El Niño occurrences, potentially changing associated regional and global climate patterns.”
The researchers suggest that this study serves as a reference point for future climate modeling efforts.
The study indicates that previous models have struggled to accurately depict the circulation patterns and sea surface temperature variations in the Pacific. The researchers believe that their findings may enhance the ability to forecast ENSO events and associated weather changes, particularly in areas like the United States, where there is considerable climate fluctuation driven by ENSO-related factors.
Support for this research was provided by NOAA’s Global Ocean Monitoring and Observing (GOMO) initiatives, which include programs such as the Global Tropical Moored Buoy Array (GTMBA), Global Drifter Program (GDP), and Tropical Atmosphere Ocean (TAO) program.
