Work

Satellite Observations Reveal Complex Zonal Shifts of Western Boundary Currents Over the Past Three Decades

Year: 2026

Type: article

Abstract: Subtropical western boundary currents (WBCs) are major conduits of ocean heat and momentum, playing a fundamental role in Earth's climate. Satellite observations reveal complex zonal movements and a pronounced meridional asymmetry in WBC shifts, yet lack a unifying explanation. Here, using quasi‐geostrophic theory and numerical experiments, we demonstrate that wind stress curl (WSC) and stratification variations compete to control WBC position: enhanced WSC drives an eastward shift, opposing the westward shift driven by stratification. This competition explains the observed divergence in zonal trends among WBCs, while meridional variations in the background potential vorticity gradient account for the asymmetric response. Our findings provide a predictive framework for assessing WBC responses to climate change.

Source: Geophysical Research Letters

DOI: 10.1029/2025gl120895

Authors: Yihang Zhang, Shuyi Zhou, Fanghua Xu

Institution: Tsinghua University

Language: English

Topic: Oceanographic and Atmospheric Processes

Subfield: Oceanography

Field: Earth and Planetary Sciences

Domain: Physical Sciences

SDG: Climate action

Open Access status: gold

Estimated APC paid: $3,190