[A-CG30] Multi-scale ocean-atmosphere interaction in the tropics

[ACG30-12] Investigation of interannual variability in the tropical Indian Ocean based on the transfer routes of wave energy

*Zimeng Li¹, Hidenori AIKI² (1.Graduate school of environmental studies, Nagoya university, 2.Institute for Space-Earth Environmental Research)

Keywords:Indian Ocean, interannual variability, wave energy, Kelvin wave, Rossby wave

We have performed a set of 61-year hindcast experiments of Indian Ocean using monthly wind forcing and provide a new perspective for the interannual variability in the tropical Indian Ocean based on the transfer routes of wave energy using a new diagnostic scheme. There are two sets of Rossby waves along the equator during 1994 IOD positive event. One is the same phase speed with theoretical phase speed of equatorial Rossby waves, the other is slightly slower than theoretical phase speed of equatorial Rossby waves. First set is the boundary-reflected equatorial Rossby waves at eastern boundary from the equatorial Kelvin waves. Second set is the off-equatorial Rossby waves generated by southeasterly winds from the southeastern Indian Ocean, which may account for the appearance of slightly slower phase speed of Rossby wave along the equator.