He plumes in the ocean

Most of the evaluation of the He plumes in the ocean has been qualitative or semi-quantitative in nature. However, there are increasing attempts to incorporate He into Ocean General Circulation Models (OGCMs) in order to understand how such models ventilate the mid-depth and deep-water masses. An early attempt of He simulations in an OGCM has been documented by Farley et al. (1995). The results of the model simulations indicate that the model can roughly close the helium balance and reproduces most of the major observed features of the He field in the ocean. At the same time, the simulations show many shortcomings of the model and future work will contribute to 

Based on the observed He excess and turnover time of the Pacific Ocean Craig et al. (1975) estimated the oceanic He flux to be 3 lxl0 atoms cm if referred to the area of the entire oceanic crust. This estimate includes both the hydrothermal He flux emanating from mid-ocean ridges as well as the crustal He flux by degassing of fhe oceanic crust. The oceanic He flux is small compared to the total He flux of ca. 1.3x10 afoms cm s (normalized fo fhe entire earth surface). 

There are specific regions in the ocean where strong He signals can be observed. For example, He excesses in the Black Sea (Top and Clarke 1983) and the Eastern Mediterranean (Roether et al. 1998) were converted into He fluxes and yielded values of 

Since these estimates of He fluxes in the mid-1970s, little work has been done that would have resulted in significant refinements of these fluxes. Simulations of the mantle helium distribution using a global general ocean circulation model (Farley et al. 1995) used a simple parameterization of the He flux from mid-ocean ridges and determined the 

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