Effects of different stratification changes on both sides of the typhoon
track on near-inertial energy propagation
Abstract
Near-inertial waves (NIWs) originate in the ocean upper mixed layer.
When they have a large horizontal scale which is characteristic of an
atmospheric storm, they are difficult to propagate vertically below the
mixed layer. The β-effect and the mesoscale vorticity are considered as
two important mechanisms for guiding the downward propagation of
near-inertial energy (NIE). In this paper, the effects of “heat
pumping” and “cold suction” of typhoons on the ocean stratification
are analyzed. It is found that changes in stratification enhance the
vertical propagation of NIWs from the mixed layer into the ocean
interior on the left side of the typhoon track. To illustrate the impact
of stratification changes on both sides of typhoon tracks, the Regional
Ocean Modelling System (ROMS) is used to simulate the NIWs generated by
Typhoon Kalmaegi in 2014. The results show that, although the wind
energy input on the right side of the typhoon track is higher than that
on the left side, the NIE injection to the deep ocean from the left side
is stronger due to the different dissipation and stratification
responses. Our work improves the understanding of the generation,
propagation, and dissipation mechanisms of NIWs during typhoons.