1. Year-round observations of the Weddell Sea from Argo floats Ethan Campbell intern Department of Geosciences Princeton University Princeton, NJ Prof. Stephen Riser mentor School of Oceanography University of Washington Seattle, WA

2. The Antarctic Circumpolar Current (ACC) and Weddell Sea Weddell Sea Stevens & Chiswell (2013) / Te Ara

3. Past observations of the Weddell Sea Extremely sparse (only 3000 ship-borne profiles since 1912) Almost all during austral summer Robertson et al. (2002) for scale, New Jersey:

4. Argo float observations National Oceanography Centre, Southampton, UK

5. Argo floats in the Weddell Sea

6. A rare occurrence during mid-winter

8. Maud Rise Massive seamount – 100 km in diameter (width of New Jersey) – Extends from 5000 m to 1600 m depth Impinging flow splits – “Halo” of circulation around column – Warm water forced to upwell Persistent low sea ice concentration Holland (2001)

9. A small polynya west of Maud Rise

10. Warm pool west of Maud Rise

11. Heat and salt budgets of the Weddell Sea mixed layer + sea ice thickness Wong & Riser (2011), from Martinson (1990) change in mixed layer depth change in mixed layer salinity inferred thermodynamic ice thickness

12. Acknowledgements Princeton Environmental Institute for funding UW School of Oceanography: – Special thanks to Prof. Stephen Riser – Annie Wong – Robert Drucker – Dana Swift – Rick Rupan & the Argo lab Princeton Atmospheric & Oceanic Sciences: – Prof. Jorge Sarmiento – Hannah Zanowski