Observations of internal waves and thermohaline structure on a drifting mooring in the Arctic Ocean during summer 2013.

In April 2013, a 600 m long bottom-mounted array consisting of receive hydrophones, thermistors and salinity sensors was deployed near the North Pole. Shortly after deployment, the array broke loose, floated to the surface where it attached to the ice sheet, and proceeded to drift south towards the Fram Strait, roughly 500 km over 5 months. Examined here are temperature and salinity variations measured on this drifting mooring over this duration with a focus on two processes - random linear internal waves and thermohaline fluctuations (spice). Internal wave spectral levels are found to be consistently lower than those predicted by the canonical Garrett-Munk (GM) spectrum, with a spectral slope closer to $\omega^{-1}$ than a typical $\omega^{-2}$ GM slope. Thermohaline variability is dominated by salinity variations with temperature fluctuations relatively insufficient to fully compensate for density along isopycnals.