Reconstructing the decadal ocean/climate variability from transient tracer observations

The penetration of anthropogenic transient tracers, such as chlorofluorocarbons (CFCs) and sulfur-hexafluoride (SF6), into the oceans represents an opportunity to trace intermediate-to-abyssal water masses as they leave the surface mixed layer and estimate the ventilation rate of the global ocean since 1940. I will present analyses based on four decades of CFCs and SF6 observations to reconstruct global tracer budgets and infer decadal variability of deep ocean circulation and tracer ventilation rates. I will also provide an overview of my research, describing how data-driven and computational methods can enhance extraction of information from invaluable yet sparse observations and inform our understanding of the large-scale ocean dynamics and their regulatory roles in the climate system. Examples include the control of Southern Ocean turbulent mixing on global ocean biochemistry and the carbon cycle, the impact of deep turbulence in the Atlantic Ocean on heat uptake and pole-to-pole transfer of anthropogenic heat, and an AI-based reconstruction of water masses and circulation in the Atlantic Ocean.  I will finish with an overview of the current state and prospects of tracer observations in the context of studying climate variability.