Special Seminar: Dr. Glenn Liu* – “Two model hierarchies for understanding the role of re-emergence and local vertical ocean dynamics in North Atlantic climate”

Subpolar north Atlantic sea surface temperatures (SSTs) are among the most persistent in the global oceans and exhibit pronounced multi-decadal variability. Despite intense focus on the region for ocean circulation and decadal climate studies, the relative importance of atmospheric versus oceanic dynamics remains a major point of contention. In this talk, I use two different model hierarchies, i.e., a stochastic climate model hierarchy and the Community Earth System Model 2 (CESM2) with hierarchy of ocean models, to demonstrate how one-dimensional ocean mixed-layer dynamics can capture key characteristics of SST variability and persistence. The hierarchy of stochastic models suggests a leading role for winter-to-winter re-emergence in SST behavior. The CESM2 with ocean model hierarchy reveals frequency-dependent contributions of horizontal versus vertical ocean dynamics by successively disabling each category of ocean processes. Finally, I apply the stochastic model hierarchy to simulating sea surface salinity variability to investigate the role of one-dimensional ocean dynamics in the broader North Atlantic region.

*The speaker has applied for research affiliate status in the Department of Oceanography

Monday, March 23, 2026, 2:00p.m., POST 414