Written by Dongmin Kim, lead author of the study and CIMAS scientist
The Atlantic Niño/Niña, characterized by warmer- or cooler-than-normal sea surface temperatures in the eastern equatorial Atlantic, was traditionally perceived to only affect environmental conditions (specifically rainfall) in and around West African countries through the Atlantic intertropical convergence zone (ITCZ) rainband. However, a recent study led by scientists at NOAA AOML and the University of Miami Cooperative Institute for Marine and Atmospheric Studies (CIMAS) found that Atlantic Niña/Niño can significantly influence Atlantic hurricane activity.
A new study led by AOML and CIMAS scientists further shows that the impacts of Atlantic Niño/Niña on tropical cyclones are not limited to the Atlantic basin (i.e., hurricanes), but also extend to the western North Pacific basin (i.e., typhoons) through inter-basin teleconnections.
The El Niño-Southern Oscillation (ENSO) has been well recognized as a major factor influencing tropical cyclone activity in the western North Pacific. However, during the early tropical cyclone season (June-August), ENSO is typically in its onset and developing phase, resulting in a relatively weaker amplitude than in the late tropical cyclone season (September-November). Thus, it is still not entirely clear what drives interannual variability of early tropical cyclone season activity.
This new study addressed this gap, showing that Atlantic Niño/Niña, the leading mode of tropical Atlantic sea surface temperature variability in June-August, plays a significant role in the early-season tropical cyclone activity in the North Pacific.
More specifically, Atlantic Niño produces anomalous upper-level convergence in the tropical western North Pacific, resulting in a decrease in low-level relative vorticity and mid-level relative humidity in the tropical western North Pacific, and an increase in low-level relative vorticity in the subtropical western North Pacific. These changes in the background atmospheric conditions lead to an increase in tropical cyclone activity over the subtropical western North Pacific and a decrease over the tropical western North Pacific.
This northward shift in tropical cyclone genesis and track density during Atlantic Niño leads to an increased risk of landfalling tropical cyclones in far eastern Asia, particularly Korea and Japan, and a decreased risk of landfalling tropical cyclones in countries surrounding the South China Sea, including Vietnam and the Philippines.
“Recent studies have demonstrated that Atlantic Niño/Niña has an important role in modulating extreme weather events globally. Thus, research on the onset/development mechanism of Atlantic Niño/Niña, along with associated ocean observations, is gaining extensive importance” said Dongmin Kim, the lead author of the study and CIMAS scientist.
These findings suggest that Atlantic Niño/Niña may serve as a key predictor for seasonal typhoon activity, especially during ENSO-neutral conditions.
References:
Kim, D., Lee, SK., Lopez, H. West, R. Foltz, GR., Hong, JS & Yeh, SW. (2025). Atlantic Niño increases early-season tropical cyclone landfall risk in Korea and Japan. npj Climate and Atmospheric Science, 8, 240. https://doi.org/10.1038/s41612-025-01112-x
Kim, D., Lee, SK., Lopez, H. Foltz, GR., Wen, C., West, R. & Dunion, J. (2023). Increase in Cape Verde hurricanes during Atlantic Niño. Nature Communications, 14, 3704. https://doi.org/10.1038/s41467-023-39467-5