Seasonal Prediction

Vinaychandran et al., (1999) investigated the role of the equatorial jets on the evolution of Indian Ocean Dipole. They studied the response of the ocean using an ocean general circulation model forced with inerannual winds. Model results showed that the eastward equatorial jets in the Indian Ocean were weak during 1994. Consequently, the sea level in the eastern Indian was unusually low, the thermocline and the mixed layer were shallow, and the subsurface flow remained eastward throughout the year. Anomalies of sea surface temperature (SST) and sea level in the eastern Indian Ocean were enhanced by upwelling favorable winds along the coast of Indonesia. The model results agree with observations and TOPEX/POSEIDON data. They suggested that the dynamical response of the ocean to wind anomalies played a role in generating the SST anomalies during 1994 Indian Ocean Dipole event and enhanced the large-scale air-sea interaction, independent of the El Nino Southern Oscillation.

Zonal currents in the equatorial Indian Ocean during 1993/94

Zonal currents in the equatorial Indian Ocean during 1993/94

Reference: P. N. Vinayachandran, N. H. Saji and Toshio Yamagata, Response of the equatorial Indian Ocean to an unusual wind event during 1994. Geophysical Research Letters, vol. 26, no 11, pages 1613-1616, 1999. (abstract, html, pdf)