LAUSR

Satellite altimetry data and high‐resolution model output are used to investigate the mechanism of interannual variations of the solitary meander in the Agulhas Current, called the Natal Pulse. It is shown that most of the Natal Pulses are triggered by anticyclonic eddies originating from the Southeast Madagascar Current (SEMC) and anticyclonic eddies of the Mozambique Channel are the secondary source. In addition to the barotropic conversion suggested by previous studies, the advection of eddy kinetic energy (EKE) plays a statistically significant role in the growth of the Natal Pulse. The number of anticyclonic eddies arriving at the Natal Bight largely explains the interannual variations in the Natal Pulse. The barotropic conversion from the SEMC, whose interannual variations are likely related to the remote wind forcing, is the main EKE source and corresponds well with the interannual variations of anticyclonic eddies generated off the southern coast of Madagascar. It is also shown that the interannual variations of the Natal Pulse are linked to large‐scale wind variability in the southern Indian Ocean. Plain Language Summary Natal Pulse is the large meander of the Agulhas Current originating in the Natal Bight and it affects both the local marine environment and global ocean circulation. Previous observational studies suggested that the occurrence of the Natal Pulse varies from year‐to‐year. Since oceanic eddies tend to trigger the Natal Pulse, we investigate the relationship between the Natal Pulse and incoming eddies in this study. We show that variations of the Natal Pulse are mainly explained by variations of eddies propagating from the south of Madagascar and the Mozambique Channel. We also show that variations in the Natal Pulse are linked to the large‐scale wind variability over the southern Indian Ocean. This study is the first to show the mechanism of the year‐to‐year variations in the Natal Pulse.