Numerical Modelling
The calculated normalized density perturbation fields (ρ − ρ 0 (z))/ρ̃ 0 and “baroclinic” u − u bt horizontal velocity values are shown in Fig. 4 for various tidal
phases. Linear barotropic tidal velocity is given by relations: u bt = V T sin(ω M 2 t)
H(x 0 )/H(x). Vlasenko et al. [19] mentioned that full periodicity of the process is
formed after 2–3 tidal periods T M 2 ; therefore, the snapshots for t ∈ [3 T M 2 ; 4 T M 2 ]
are shown.
Time moment 3T M 2 corresponds to the end of the ebb phase and the beginning of
the flood phase. The velocity of the tide at 3T M 2 is zero and there are large perturbations of density (and corresponding displacements of isopycnals) over the left
(western) side of the largest hill. Intense IWs are generated over the slopes of the
highest central hill (located between 200 and 300 km, while the crest is at 230 km).
Their amplitudes decrease when they propagate out of this zone. After a quarter of
the tidal period, at t = 3.25 T M 2 , the tidal flood phase starts; the velocities reach the
maxima, and the wave generation intensifies at the right lee slope of the central hill.
At time moment t = 3.5 T M 2 , the phase of the flood finishes, and the barotropic tidal
velocities vanish; the IWs are developed well on the right side of the central hill.
When the ebb phase is maximal (at t = 3.75 T M 2 ), the zone of generation is also
shifted to the other (left) lee side of the hill, and the waves gain the largest
amplitude at t = 4 T M 2 when the velocity of the barotropic tide vanishes again.
The density perturbation shown in the left column in Fig. 4 perfectly illustrates
the phenomena of upwelling and dowelling caused by the interaction of the barotropic tidal flow with the bottom topography. The difference between densities of
Fig. 3 Typical vertical mean profile of the potential density anomaly (1026–1028 kg/m
3
)
ρ 0 (z) (a); Brunt–Väisälä frequency (b) in the study site taken from the GDEM climatology for July
Numerical Modeling of Internal Wave Generation at High Latitudes
573
The calculated normalized density perturbation fields (ρ − ρ 0 (z))/ρ̃ 0 and “baroclinic” u − u bt horizontal velocity values are shown in Fig. 4 for various tidal
phases. Linear barotropic tidal velocity is given by relations: u bt = V T sin(ω M 2 t)
H(x 0 )/H(x). Vlasenko et al. [19] mentioned that full periodicity of the process is
formed after 2–3 tidal periods T M 2 ; therefore, the snapshots for t ∈ [3 T M 2 ; 4 T M 2 ]
are shown.
Time moment 3T M 2 corresponds to the end of the ebb phase and the beginning of
the flood phase. The velocity of the tide at 3T M 2 is zero and there are large perturbations of density (and corresponding displacements of isopycnals) over the left
(western) side of the largest hill. Intense IWs are generated over the slopes of the
highest central hill (located between 200 and 300 km, while the crest is at 230 km).
Their amplitudes decrease when they propagate out of this zone. After a quarter of
the tidal period, at t = 3.25 T M 2 , the tidal flood phase starts; the velocities reach the
maxima, and the wave generation intensifies at the right lee slope of the central hill.
At time moment t = 3.5 T M 2 , the phase of the flood finishes, and the barotropic tidal
velocities vanish; the IWs are developed well on the right side of the central hill.
When the ebb phase is maximal (at t = 3.75 T M 2 ), the zone of generation is also
shifted to the other (left) lee side of the hill, and the waves gain the largest
amplitude at t = 4 T M 2 when the velocity of the barotropic tide vanishes again.
The density perturbation shown in the left column in Fig. 4 perfectly illustrates
the phenomena of upwelling and dowelling caused by the interaction of the barotropic tidal flow with the bottom topography. The difference between densities of
Fig. 3 Typical vertical mean profile of the potential density anomaly (1026–1028 kg/m
3
)
ρ 0 (z) (a); Brunt–Väisälä frequency (b) in the study site taken from the GDEM climatology for July
Numerical Modeling of Internal Wave Generation at High Latitudes
573