Roughan Moninya (University of NSW, Australia)

Frontal eddies are sub-mesoscale cyclonic features that are especially prone to form on the landward side of western boundary currents. In June 2015, a team of scientists lead by Iain Suthers of UNSW used Australia's new research vessel RV Investigator to intensively sample a 30km-diameter frontal eddy that formed near Sydney, inshore of the East Australian current. The formation of the eddy (first detected in SST imagery) during the voyage was very fortuitous. Even more fortuitous was the perfect coincidence of the in-situ sampling and the overflight of Altika, which determined the central anomaly of sea level to be -15cm, in close agreement with the central anomaly of dynamic height. Geostrophic estimates of cross-track velocity of ~1m/s agree well with the vessel's ADCP and the velocity of buoys released into the eddy.