New ice core proxy for reconstructing past wind variability in the Atlantic sector of the Southern Hemisphere Westerly Wind belt

The Southern Hemisphere Westerly Winds play a critical role in the global climate system by modulating the upwelling and the transfer of heat and carbon between the atmosphere and the ocean. Since observations started, the core of the westerly wind belt has increased in strength and has contracted towards Antarctica. It has been proposed that these deviations are among the main drivers of the observed widespread warming in West Antarctica. However, the lack of long-term wind records in the Southern Hemisphere mid-latitudes hinders our ability to assess the wider context of the recently observed changes.

Here, we present the diatom record preserved in an ice core retrieved from the Ellsworth Land region, West Antarctica. The diatom abundances and species assemblages from this ice core represent the regional variability in wind strength and atmospheric circulation patterns over the Atlantic sector of the Southern Ocean. We use this novel proxy to produce an annual reconstruction of winds in the Atlantic sector of the Southern Hemisphere Westerly Wind belt over the last 300 years. This wind reconstruction allows tracking changes in the strength and position of the westerly winds during the late Little Ice age and exploring the link between the recent increase in wind strength, greenhouse gases and ozone depletion in the atmosphere.