Characteristics of thermohaline staircases in the Southeast Caribbean sea revealed by seismic reflection data

Abstract

Seismic oceanography, characterized by its high horizontal resolution and large imaging coverage, can be used to directly measure the horizontal extension of the thermohaline staircase. This study presents an investigation into the seismic reflection imaging of thermohaline staircases located in the Southeast Caribbean Sea. The findings indicate clear interactions between the staircases and various structures, such as eddies and internal waves. The pre-stack migration method based on common offset gathers is applied to analyze the changes of the thermohaline staircase over different times along line L3. The distributions of dissipation rates within 900 m depth are obtained. The findings indicate the internal wave activity and turbulence in the vicinity of the staircase are locally low. This restraint may support the continuous and enduring presence of the staircase in this region. However, the staircase region away from the eddy has a limited restraining effect on the internal wave, and its intense activity causes intense turbulence, which destroys staircase structure. Our results indicate that the reflection coefficients of the thermohaline staircase and intrusions on the seismic section exhibit opposite polarities. There exists certain intrusion structure within the staircase at the flank of eddy.