CFC Tracer

A CFC tracer is the use of dissolved chlorofluorocarbons, mainly CFC-11 and CFC-12, as transient tracers of ocean ventilation. These gases are purely anthropogenic, with an atmospheric history that rose from the 1930s, peaked around the 1990s, then declined under the Montreal Protocol. Because surface water equilibrates with this known time-varying atmosphere, the CFC content of a deep water parcel dates when it was last at the surface and traces the spreading of recently ventilated water masses. CFC ages and the CFC-11/CFC-12 ratio map ventilation rates and the penetration of anthropogenic carbon, work extended by SF6 as CFC levels fall.