Interannual variability of the Shelfbreak Jet on the New Jersey Shelf as inferred from CMV Oleander observations

Repeat measurements of velocity and temperature profiles from the CMV Oleander provide an unprecedented look into the variability on the New Jersey Shelf and upper continental slope. Here 1362 velocity sections collected between 1994-2018 and 545 temperature sections from 1977-2018 are analyzed to characterize seasonal to decadal changes in the Shelfbreak Jet and to examine how Shelfbreak Jet variability relates to the temperature variability on the shelf. The Shelfbreak Jet can be identified in approximately 60% of the ADCP sections. Mean Eulerian Shelfbreak Jet velocities reach a maximum of 12 cm/s while mean velocities calculated in a steam-coordinate frame aligned by the jet’s velocity maximum reach 25 cm/s. The structure and velocity of the streamwise jet reflect calculations from climatological hydrography better than the Eulerian jet. The Shelfbreak Jet is strongest in the spring and weakest during the summer months. During time periods when the shelf and slope are relatively cooler, the Shelfbreak Jet can be identified over 80% of the time, and is relatively faster. The cross-correlations between velocity and temperature are significant at a broad range of lags centered around a 2-month lag, with velocity leading temperature. Both the Shelfbreak Jet velocity and the shelf temperature have significant variability at 2-5 year long periods. The coherence between these two signals is currently being studied as is variability in the neighboring Slope Jet, which is also well sampled by the Oleander sections.