Use of SF₅CF₃ for ocean tracer release experiments

SF 6 tracer release experiments (TREs) have provided fundamental insights in many areas of Oceanography. Recently, SF 6 has emerged as a powerful transient tracer, generating a need for an alternative tracer for large‐scale ocean TREs. SF 5 CF 3 has the potential to replace SF 6 in TREs, due to similarities in their properties and behavior, as well as techniques for injection, sampling, and analysis. The suitability of SF 5 CF 3 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 SF 6 and SF 5 CF 3 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 SF 5 CF 3 is a viable replacement for SF 6 in ocean TREs. The mixing parameters inferred from the experiment confirmed the results from an earlier SF 6 TRE in the Santa Monica Basin.