← Back to Sessions

Ocean Bottom Turbulence Evolution Observed by Arrayed Obs, Dpg, and a Temperature String

Description: 

Turbulent mixing in the deep sea is not well understood due to lack of long-term in-situ observation. The breaking of internal waves on sloped seafloor topography can generate turbulence that is difficult to measure comprehensively due to its multi-scale processes, in addition to the flow-flow, and flow-topography interactions. Here we deploy a high-resolution spatiotemporal array of four ocean bottom seismometers (OBS) and a 200-m vertical temperature string at 3000-meter water depth in a footprint of 1 X 1 km, in order to characterize turbulence induced by internal waves. Each OBS is also equipped with a differential pressure gauge (DPG). We found that the OBS has recorded signals induced by near-seafloor turbulence, particularly during typhoon periods. We propose that large-scale inertial breaking has occurred with upslope transport speeds of 0.2 to 0.5 m s^-1. We also found evidence of small-scale bathymetry causing localized wave breaking. Data from the DPG and the temperature string also document internal waves and turbulent motions, with a frequency of 0.002 to 0.1 mHz. Applying beamforming-frequency-wavenumber analysis and linear regress to the arrayed Temperature sensor and DPG, we estimated a transport speed similar to that derived from the OBS. Arrayed OBS can provide complementary observations to characterize deep-sea turbulence.

Session: Marine Seismoacoustics - I

Type: Oral

Date: 5/1/2024

Presentation Time: 05:15 PM (local time)

Presenting Author: Wu-Cheng

Student Presenter: No

Invited Presentation: 

Authors