第八届全国中尺度气象学研讨会

A recent study distinguishes two variants of the Atlantic Niño, characterized by warming concentrated in the central (CA) and eastern (EA) equatorial Atlantic, respectively. Through an analysis of observational and reanalysis data, we investigated how these two types of Atlantic Niño affect tropical cyclone activity in the Atlantic and the western North Pacific (WNP) . The findings reveal that the CA Niño enhances hurricane frequency south of 20°N, while the CA Niña promotes hurricanes north of 20°N. The CA Niño exerts a more significant influence on hurricanes than the EA Niño, primarily by affecting wind shear, relative vorticity, and vertical velocity. In contrast, the EA Niño mainly impacts relative humidity and African Easterly Waves. Concurrently, analysis of WNP reveals that CA events drive a meridional dipole in TC formation, while EA impacts are weaker and less organized. These differential effects stem from the contrasting modulation of large-scale environmental conditions—including vertical wind shear, vorticity, vertical motion, and mid-level humidity. Collectively, these findings offer critical mechanistic insights that could substantially enhance the accuracy of seasonal hurricane and TC forecasts.

Atlantic Niño,tropical cyclone,Western North Pacific

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