615 / 2024-09-18 16:32:53

Estimate the interannual variability of subtropical AMOC using sea surface height

AMOC, sea surface height, variability

Session 41 - The Atlantic Meridional Overturning Circulation Variability and its Climatic Impacts

As a key ocean mechanism in the global climate system, the Atlantic Meridional Overturning Circulation (AMOC) can redistribute heat, salt and other biochemical components throughout the ocean. However, due to the methodological and financial constraints, current AMOC observations are limited to individual latitudes and a relatively short time span. To overcome these limitations and explore the AMOC variability, finding a potential proxy may be helpful and crucial. Sea surface height is considered as a feasible choice. Using satellite and cable observations, we have reconstructed the subtropical AMOC time series on the interannual time scale since 1993. Our results indicate that sea surface height is an effective proxy for subtropical AMOC. The interannual fluctuations of subtropical AMOC range within ±2 Sv, primarily influenced by the upper mid-ocean geostrophic transport and Gulf Stream. During some special periods such as 2010, the anomalous Ekman transport also has a significant contribution. This interannual variability is more likely to be driven by local winds in the subtropical region.