Abstract: The interaction of mode-1 internal tides with a geostrophic current (Ocean Sciences Meeting 2020)

The interaction of mode-1 internal tides with a geostrophic current

Yangxin He, University of Waterloo, Department of Applied Math, Waterloo, ON, Canada and Kevin G Lamb, Univ Waterloo, Waterloo, ON, Canada

Abstract:

We examine the reflection and transmission of mode-1 internal
tides (ITs) propagating across a geostrophic current, such as the Gulf
Stream, in a two dimensional setting. The current is modeled as an idealized Gaussian function with width

x_{r}

and length

z_{r}

. Depending on the current parameters and the Coriolis parameter

f

, the effective frequency

σ_{e f f}

can be smaller or larger than the IT frequency

σ

, resulting in weak or strong reflections from the ITs impinging
on the current. Our analysis is mainly focused on 1) the reflection coefficient

R

of the ITs
from the current and 2) the energy in the linear modes

P_{n}

, where

n

is the modal
number, produced after the waves propagate through the
current. There exists a region of

x_{r}

and

z_{r}

, that
maximizes

R

and

P_{n}

, respectively. The values of

R

and

P_{n}

slowly decrease as

x_{r}

and

z_{r}

move away from the region. A linear theory of

R

from internal waves normally incident on a linear barotropic current is presented.

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