2000. The American Astronomical Society. All rights reserved. Printed in U.S.A.( SIGNATURES OF THE RISE OF CYCLE 23

During the rise of Cycle 23, we have found a sizable, systematic evolution of the Solar and Helio-spheric Observatory/Michelson Doppler Imager solar oscillation frequencies implying signiÐcant changes in the spherically symmetric structure of the SunÏs outer layers as well as in its asphericity up to a P18Legendre distortion. We conducted a search for corresponding asymmetries in Ca II K data from Big Bear Solar Observatory. We found tight temporal and angular correlations of the respective asphericities up through This result emphasizes the role of the magnetic Ðeld in producing the frequencyP10.changes. We carried out inversions of the frequency dierences and the splitting coefficients assuming that the source of the evolving changes is a varying stochastic magnetic Ðeld. With respect to the most recent activity minimum, we detected a signiÐcant perturbation in the spherical part at a depth of 25È100 Mm, which may be interpreted as being a result of a magnetic perturbation, SB2T, of about (60KG)2 and/or a relative temperature perturbation of about 1.2] 10~4. Larger, although less sta-tistically signiÐcant, perturbations of the interior structure were found in the aspherical distortion. Subject headings: Sun: interior È Sun: oscillations 1