Warming of the Southern Ocean: inter-annual, decadal, and long-term variability
Date
2019
Authors
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Publisher
University of Delaware
Abstract
Over the past decade, the Southern Ocean (SO) has been a subject of intense research but due to the complex dynamics it continues to be an area not well understood. Knowledge of the heat distribution and variability throughout the entire SO is critical to understanding the global climate system as a whole and its variability. In this study, a new reanalysis data product known as the ORAS5 was used to better understand the SO’s surface and subsurface warming over the past four decades. The inter-annual and decadal variability, and the long-term trends highlighted the importance of both natural and anthropogenic forcings on SO warming. Climate oscillations such as ENSO and SAM showed a large causal relationship on the SO surface temperatures on inter-annual scales, while SAM was more causal of SO OHC patterns on decadal or longer time scales. Such results suggest that the decadal variability of SO heat content is related to natural circulation and mixing patterns, while the increasing long-term trend is due to global warming. The results from the causal relationship between the global mean surface temperature and the SO heat content provide further insight on the strong influence the SO’s warming has on the global climate system. Despite changes within the overall SO, local variations between the surface and subsurface temperatures were also studied and related to atmospheric teleconnections and topographic features.
Description
Keywords
Ocean heat content, Sea-surface temperature, Southern Ocean