Impact of Indian Ocean Dipole on intraseasonal zonal currents at 90°E on the equator as revealed by self‐organizing map

A neural network pattern recognition approach called self-organizing map (SOM) has been used to examine the impact of the Indian Ocean Dipole (IOD) on intraseasonal zonal currents in the eastern equatorial Indian Ocean. This study shows that during negative IOD events the intraseasonal zonal currents are mostly dominated by the first two modes. On the other hand, contributions from the higher modes to the intraseasonal zonal current significantly increase during positive IOD events. This is attributed to the change in the background stratification associated with the IOD events; the sharp pycnocline in the eastern basin during the positive IOD events causes the wind forcing to project more onto the higher modes.

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