Constraints on mantle ³He fluxes and deep-sea circulation from an oceanic general circulation model

The steady-state distribution of helium in the deep sea has been simulated to investigate the magnitude and spatial and temporal variability of mantle degassing and to characterize deep-sea circulation and ventilation. The simulation was produced by linking a simple source function for helium injected at mid-ocean ridges with an oceanic general circulation model (GCM). While the results generally support the GCM's abyssal circulation, the simulation reveals regions of overly-intense lateral diffusion and upwelling in the model, particularly in the equatorial Pacific. Similarly, there appears to be insufficient production of He-ventilated bottom waters in the model Antarctic. These observations suggest that further refinement of the GCM abyssal circulation is required. -from Authors