Use of SF5CF3 for ocean tracer release experiments

SF6 tracer release experiments (TREs) have provided fundamental insights in many areas of Oceanography. Recently, SF6 has emerged as a powerful transient tracer, generating a need for an alternative tracer for large-scale ocean TREs. SF5CF3 has the potential to replace SF6 in TREs, due to similarities in their properties and behavior, as well as techniques for injection, sampling, and analysis. The suitability of SF5CF3 for TREs was examined in Santa Monica Basin, off the coast of Southern California. In January 2005, a mixture of ca. 10 mol of both SF6 and SF5CF3 was injected on an isopycnal surface near 800 m depth. Over the next 23 months, concentrations of the two tracers mirrored each other very closely, indicating that SF5CF3 is a viable replacement for SF6 in ocean TREs. The mixing parameters inferred from the experiment confirmed the results from an earlier SF6 TRE in the Santa Monica Basin.