Different life spans of sunspots suggest their origin at different depths, and by measuring magnetic fluxes from their first observation on the surface, one can estimate the strength of magnetic flux at different anchoring depths. From SOHO MDI magnetograms, we infer the strength of magnetic flux and rate of emergence of magnetic flux at different anchoring depths in the solar convective envelope by measuring initial magnetic fluxes of the well-developed sunspots on the surface. Important findings are: (1) the majority of the spot groups that have first observation on the surface are bipolar; (2) irrespective of their sizes, the bipolar spots with different life spans have average magnetic field strengths of ~500 G during their first observation; (3) the average field strength at the site of anchoring depths of the sunspots is estimated to be ~106 G near the base of the convective envelope and ~104 G near the surface; (4) the dynamo—a source of sunspot activity—is distributed throughout the convective envelope; and (5) the rate of emergence of initial magnetic flux of such a distributed dynamo near the base of the convection zone is ~6 × 1019 Mx day-1 and is 40% higher than the rate of emergence of initial magnetic flux near the surface.
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