Signatures of the rise of Cycle 23

During the rise of Cycle 23, we have found a sizable, systematic evolution of the Solar and Heliospheric Observatory/Michelson Doppler Imager solar os cillation frequencies implying significant changes in the spherically symme tric structure of the Sun's outer layers as well as in its asphericity up t o a P-18 Legendre distortion. We conducted a search for corresponding asymm etries in Ca II K data from Big Bear Solar Observatory. Ne found tight temp oral and angular correlations of the respective asphericities up through P- 10. This result emphasizes the role of the magnetic held in producing the f requency changes. Ne carried out inversions of the frequency differences an d the splitting coefficients assuming that the source of the evolving chang es is a varying stochastic magnetic held. With respect to the most recent a ctivity minimum, we detected a significant perturbation in the spherical pa rt at a depth of 25-100 Mm, which may be interpreted as being a result of a magnetic perturbation, "B-2", of about (60KG)(2) and/or a relative tempera ture perturbation of about 1.2 x 10(-4). Larger, although less statisticall y significant, perturbations of the interior structure were found in the as pherical distortion.