Eddy-fying Research: Understanding Properties of Southern Ocean Eddies Intern: Bridget Zakrzewski Mentor: Ivy Frenger How can we combine surface and sub-surface data to observe mesoscale eddies?

What Is An Eddy? Whirlpools Part of ocean turbulence Importance: - Mixing and water-mass transport - Tracer distribution & ocean dynamics (Southern Hemisphere) Drake Passage Eddy, NASA

How Can We Observe Eddies? Altimetry (AVISO – 1992) (spatio-temporal coverage, no sub-surface data) In-Situ Data (Argo – early 2000s) (Vertical structure, less spatio-temporal coverage) Both (get the benefits of each!)

ACC Eddies Antarctic Circumpolar Current (ACC) surrounds Antarctica ACC is largest current in the world Southern Ocean dynamics South ACC North ACC North ACC North ACC Eddy anomalies shown above. Note: North of ACC = outside of ACC, South of ACC = inside of ACC

Eddies near South Western Australia (or “Weird” Eddies) Cyclones with positive anomaly Maximum life span of 72+ weeks (Courtesy of Ivy Frenger)

“Weird” Eddy Anomalies (3+ months) (Sorted by eddy lifespan) Bin1: <22wks Bin5: 52-61wks Bin2: 22-31wks Bin6: 62-71wks Bin3: 32-41wks Bin7: 72-81wks Bin4: 42-51wks Bin8: >82wks

Possible Origins of “Weird” Eddies Warm surface boundary currents Eddy-rich currents

Potential Future Research Take a closer look at salinity anomaly crossing Observe eddies near other boundary currents Use absolute values, not anomalies Understand differences in slopes for anticyclones vs. cyclones

Acknowledgements For the continuous support throughout my summer experience, I would like to thank: Ivy Frenger, Mentor Professor Jorge Sarmiento, Host AOS/GFDL community, Support Princeton Environment Institute (PEI)