High-Resolution Modeling of Semidiurnal Internal Tidal Waves in the Laptev Sea in the Ice-Free Period: Their Dynamics and Energetics

Abstract

The QUODDY-4 three-dimensional finite-element hydrostatic model has been used to reproduce the spatial distributions of dynamic and energetic characteristics of the internal tidal waves (ITWs) of the Laptev Sea in the ice-free period. It has been shown that one distinctive feature of ITW amplitudes at the pycnocline depth is that the area with relatively high ITW amplitudes is limited. The peak amplitudes reaching at least 5 m have been detected only in the central part of the sea near the continental slope, but the ITW amplitudes in the western and eastern parts of the sea do not exceed 0.2 and 0.1 m, respectively. Like ITW amplitudes, the baroclinic tidal velocities are expressed mainly in the central part of the sea and almost vanish in its western and eastern parts. The presence of a zone of high baroclinic velocities near the northern open border of the sea and an increase in velocities with approaching the coast of the continent at the mouth of the Lena River is noted. The fields of components of the averaged (over a tidal cycle) baroclinic tidal energy budget (integrated by depth) are discussed. The averaged (over the sea area) values of the density of baroclinic tidal energy, as well as the tidal energy conversion and dissipation rates, are $$1.2\,\, \times \,\,{{10}^{3}}$$ J/m2, $$ - 0.3\,\, \times \,\,{{10}^{{ - 3}}}$$ W/m2, and $$7.3\,\, \times \,\,{{10}^{{ - 3}}}$$ W/m2, respectively. The ITW lifetime in the Laptev Sea, defined as the ratio of the average density of baroclinic tidal energy to the dissipation rate, is around 50 h; i.e., the ITW lifetime in the sea is 4 times higher than the tidal cycle length for the M2 tidal harmonic.