Project description
Quantifying the hydrographic fingerprint of the overturning water circulation
As a continuous ring of water around Antarctica, the Southern Ocean links all other oceans. The process of overturning circulation influences powerfully Earth’s climate. While numerical studies suggest there are substantial variations in the overturning circulation due to increased westerly winds, there is a lack of observational evidence that these variations have occurred or are occurring in oceanographic measurements. The EU-funded SOFIE project aims to detect and measure the hydrographic fingerprint of changes in this overturning. SOFIE proposes that changes in the overturning circulation affect noticeably the ocean interior density structure from surface to depth across the Southern Ocean. It will test this hypothesis in the state-of-the-art numerical NEMO-OPA model.
Objective
The Southern Ocean overturning circulation exerts a powerful influence on Earth’s climate, and SOFIE is the first project seeking to detect and objectively measure the hydrographic fingerprint of changes in this overturning.The deep waters upwelling in the Southern Ocean account for up to half of the annual oceanic uptake of anthropogenic carbon from the atmosphere, dominate the global oceanic heat uptake with up to three quarters of the additional heat influx to the ocean occurring south of 30°S, and are a rich source of the nutrients that fertilise the majority of global ocean biological productivity north of 30°S.According to numerical studies, there is consensus that in response to increased westerly winds such as those occurring within contemporary climate change, variations in the overturning circulation are likely to be substantial.However there is no established approach to provide observational evidence that these variations have occurred or are occurring in oceanographic measurements;and the lack of such an approach stems from the uncertain fingerprint of Southern Ocean overturning circulation changes on measurable oceanographic variables.Based on preliminary results supported by recent studies, SOFIE proposes that changes in the overturning circulation affect discernibly the ocean interior density structure from surface to depth across the Southern Ocean.We will rigorously test this hypothesis in the state-of-the-art numerical NEMO-OPA model, and assess in-situ evidence of overturning changes from the pan–Antarctic Argo network.To do this, SOFIE will combine model diagnostics of the Southern Ocean overturning circulation with the application to the model and in-situ fields of a novel algorithm characterising the vertical structure of the ocean.Given the ocean overturning’s sensitivity to changes in atmospheric forcing,SOFIE results will be a major step to constrain the changing ability of the Southern Ocean to slow down the rate of global climate change.
Fields of science
Programme(s)
Funding Scheme
MSCA-IF - Marie Skłodowska-Curie Individual Fellowships (IF)Coordinator
SO17 1BJ Southampton
United Kingdom