Speaker: Yuchen Ma, Departments of Earth, Atmosphere and Planetary Sciences, Massachusetts Institute of Technology

Time: 14:00-15:30 p.m., Dec 19, 2024, GMT+8

Venue: Room 210, Building #1, College of Engineering, PKU

Abstract: 

Thermohaline staircases, characterized by stepped vertical profiles of temperature and salinity, are common in the Arctic Ocean, yet their formation mechanism remains debated. While staircases in low-latitude regions are well understood to arise from small-scale salt-fingering instabilities, the widely held view that Arctic staircases result from double-diffusive processes lacks clarity. Our research reveals a novel mechanism, showing that stratified turbulence, rather than double-diffusive instability, may drive the formation of Arctic staircases. This mechanism aligns with observations and is supported by direct numerical simulations, which also elucidate the small-scale turbulent processes that stabilize these structures. These findings challenge conventional theories and emphasize turbulence's role in shaping thermohaline staircases and control the heat transport through these staircase structures.

Source: College of Engineering, PKU