Enhanced generation of internal tides under global warming

Area of Science:

• Oceanography
• Climate Science
• Geophysics

Background:

• Deep-ocean mixing is primarily driven by the breaking of internal tides.
• Internal tides are generated by the interaction of barotropic tides with seafloor topography.
• Understanding the impact of global warming on this energy conversion is crucial for climate projections.

Purpose of the Study:

• To investigate how global warming affects the energy conversion from barotropic to internal tides.
• To quantify the projected changes in internal tide energy conversion under a high carbon emission scenario.

Main Methods:

• Utilized a linear model of internal tide generation.
• Applied the model to coupled global climate model simulations.
• Simulated a high carbon emission scenario through the end of the 21st century.

Main Results:

• Projected an approximate 8% rise in energy conversion to high-mode internal tides by 2100.
• Observed minimal change in energy conversion to low-mode internal tides.
• Found that intensified near-bottom stratification boosts conversion to both low and high-mode internal tides.
• Noted that intensified depth-averaged stratification shifts energy towards high-mode internal tides.

Conclusions:

• Global warming is expected to intensify deep-ocean mixing over rough topography.
• These changes necessitate improved parameterization in climate models for accurate future climate change projections.