ИСТИНА

Internal Tidal Wave Propagation under the Landfast Sea Ice in the Southeast Hudson Bay. Hudson Bay (HB) is the second-largest saltwater bay in the world. It is relatively shallow with an average depth of 100m and high tidal amplitudes (up to about 4m). Several major rivers are discharging into HB currently being regulated due to hydro dam development causing freshwater discharge to increase in winter months. All these factors make HB a unique oceanographic system for study atmospheric-oceanographic coupling and freshwater impact. During January-March 2014 the CTD survey was conducted around Belcher islands in the southeastern HB. An ice-tethered mooring consisting of 9 conductivity and temperature (CT) sensors and acoustic Doppler current profiler (ADCP) was deployed in a narrow channel between Broomfield and O’Leary islands located in the southeast tip of Belcher islands group in HB as a part of an oceanographic monitoring program in that region. The CTD profiles show the surface freshened layer caused by cyclonic circulation of river runoff water in Hudson Bay. In the bottom layer, warm and saline water was recorded increasing meridionally towards the south. Such layer preserved in the south due to presence of salinity/density vertical stratification that prevents vertical mixing. The mooring recorded semidiurnal oscillations of temperature and salinity through the whole water column. Our objective was to examine the origin of this temperature and salinity variability. The tidal analysis was performed for M2 as the main tidal constitutes. The tidal ellipses were computed for the horizontal velocity at various depths with an overlay of corresponding salinity and temperature values. From the mooring time series, the M2 temperature and salinity amplitudes were calculated for each depth. These plots as well as the tidal ellipses showed a pattern typical for internal waves. Based on velocity, temperature and salinity data and tidal analysis we came to the conclusion that our mooring recorded internal tidal waves produced from the interaction of tides with bathymetry of the narrow channel between Broomfield and O’Leary islands