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Hydrographic-Tracer Relationships:

On the Calculation of Total Heat, Salt and Tracer Fluxes from Ocean Hydrothermal Events (Abstract)

Problem Description:
Estimates of heat released during event plume formation usually are based on volume integrals of the resulting temperature anomalies measured in the water column. Anomaly distributions, however, depend on anomaly definition. The most commonly used definition of anomaly, defined as the difference between plume and ambient values for points of equal density, leads to volume integrals that do not represent the actual total heat flux released during an event. Why is that and what must be done with that estimate to get the correct value? This study establishes a factor, f_theta shown here, for rescaling apparent heat flux to actual heat flux. The analysis also leads to a relationship between the ratio of tracer to heat anomalies measured anywhere in an event plume to a similar ratio at the event source.

model images, click for large size

The variable f_theta rescales the total apparent heat, based on the volume integral of density-density temperature anomalies, to the total actual heat discharged during a megaplume event. Site differences in hydrography:

a) Juan de Fuca Ridge
b) East Pacific Rise
c) Mid-Atlantic Ridge

The magnitude of f_theta depends on event plume source temperature and salinity.

click for larger view


Related Papers:

Lavelle, J.W., E.T. Baker, and G.J. Massoth (1998): On the calculation of total heat, salt and tracer fluxes from ocean hydrothermal events. Deep-Sea Res. II, 45(12), 2619-2636.


  Modeling focuses: Chronic focused-source | Event Plumes | Axial Valley transport | Ridge Flow | Geochemical Transport | Hydrographic-Tracer Relationships