Volume Transports of the Wyrtki Jets

Abstract:

The equatorial Indian Ocean is characterized by strong eastward surface flows in boreal spring and fall referred to as the Wyrtki jets. These jets are driven by westerly winds during the transition seasons between the Southwest and Northeast Monsoons and represent a major conduit for mass, heat, and salt transfer between the eastern and western sides of the basin. Since their discovery over 40 years ago, there have been very few estimates from direct observations of the volume transports associated with these currents. In this presentation we will describe seasonal to interannual time scale variations in volume transport based on four years of unique measurements from a meridional array of acoustic Doppler current profilers along 80°5E in the center of the basin. The relation of these transports to zonal wind stress forcing, sea surface height variations and sea surface temperature variations in association with the Indian Ocean Dipole will be highlighted. We will also illustrate the role of wind-forced equatorial waves in affecting transport variations.