Internal tide in the Kara Gates Strait

Abstract

We observed strong internal tidal waves in the Kara Gates Strait. Internal tides are superimposed over a system of mean currents from the Barents to the Kara Sea. Field studies of internal tides in the Kara Gates were performed in 1997, 2007, and 2015. In 2015, we analyzed data from towed CTD measurements, numerical model calculations, and satellite images in the region. An internal tidal wave with a period of 12.4 h is generated due to the interaction between the currents of the barotropic tide and the bottom relief on the slopes of a ridge that crosses the strait from Novaya Zemlya to the continent. The depths of the ridge crest are 30–40 m. A constant current of relatively warm water flows from the Barents to the Kara Sea. An internal wave propagates in both directions from the ridge. In the Barents Sea, internal waves are intensified by the current from the Barents to the Kara Sea. Internal bores followed by a packet of short-period internal waves are found in both directions from the strait. Satellite images show that short-period internal waves are generated after the internal bore. A hydraulic jump was found on the eastern side of the strait. Numerical modeling agrees with the experimental results.