Late quaternary changes in the westerly winds over the Southern Ocean – a progress report

Hodgson, DA; Roberts, S; Perren, B; Saunders, KM; Verleyen, E; van Nieuwenhuyze, W; Vyverman, W; Sime, L

Late quaternary changes in the westerly winds over the Southern Ocean – a progress report

Date

2016-01-18

Authors

Publisher

VII Southern Connection Congress 2016

Abstract

The Southern Hemisphere westerly winds (SHW) are the strongest time-averaged oceanic winds. They drive the circulation of the Southern Ocean and changes in their strength and position are thought to modify the upwelling of carbon rich deep water, exerting significant control on the ocean-atmosphere balance of CO2. Thus changes in the SHW, such as the recently observed intensification, could influence whether the Southern Ocean acts as a net source or sink of atmospheric CO2, with major implications for global climate. At present the relationships between wind strength, CO2 and climate are poorly understood and there are very few studies within the core belt of the SHW in the sub-Antarctic zone c.46 to 60 deg South. We have been attempting to address this by producing centennial to decadal reconstructions of changes in SHW strength at sub-Antarctic islands in each of the major sectors of the Southern Ocean. In this talk we will show how lake sediments and peat deposits on the west coasts of these islands can yield proxy-based reconstructions of past changes in the SHW. We will review the statistical performance of our inference models, their application down selected sediment cores, and compare them with complimentary proxies of changes in wind strength based on precipitation and minerogenic inputs. The next phase of the project will use GCM simulations to help understand the patterns seen in the observational data and identify the drivers of past changes in the SHW.

Keywords

Wind, Seas, Water, Climates, Data, Carbon dioxide injection

Citation

Hodgson, P., Roberts, S., Perren, B., Saunders, K., Verleyen, E., van Nieuwenhuyze, W., Vyverman, W., & Sime, L. (2016). Late quaternary changes in the westerly winds over the Southern Ocean – a progress report. Paper presented at the VII Southern Connection Congress 2016, Punta Arenas, Chile, 18-23 January, 2016.