Multidecadal Intensification of Atlantic Tropical Instability Waves

Tropical Instability Waves (TIWs) are the dominant source of intraseasonal variability in central equatorial Atlantic and play an important role redistribution heat upper ocean. Here we use multidecadal records sea surface temperature, level anomaly, salinity, near-surface currents constructed from situ satellite observations to reveal a long-term intensification these variables due increase TIW activity. Enhanced barotropic energy conversion increased covariance horizontal current fluctuations, rather than low-frequency changes mean zonal currents, drives intensification. As consequence, boreal summer cooling tropical North waters through eddy temperature advection by 0.03°C month-1 decade-1 during 1993-2021, change 74 ± 53% relative mean. The presented trends strongly modulated interannual variations like 2021 Niño.