AAS Meeting #194 - Chicago, Illinois, May/June 1999
Session 56. New Views of the Solar Interior
Solar, Display, Tuesday, June 1, 1999, 10:00am-7:00pm, Southeast Exhibit Hall

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[56.02] Solar Internal Rotation as Measured by the SOHO SOI/MDI Full-Disk Program

E.J. Rhodes,Jr. (USC AND JPL), J. Reiter (Tech. Univ. Munich), A.G. Kosovichev, J. Schou, P.H. Scherrer (Stanford U.)

We present estimates of the solar internal angular velocity obtained from p-mode frequency splittings computed from observations of the SOHO SOI/MDI Experiment's Full-Disk Program. Specifically, a time series of full-disk Dopplergrams which was obtained during the 61-day long 1996 Dynamics Run of the SOI/MDI Experiment were converted into time series of spherical harmonic coeffificients for degrees ranging up to 1000. These time series of spherical harmonic coefficients were then converted into 1001 sets of zonal, sectoral, and tesseral power spectra. Estimates of the rotationally-induced p-mode frequency splittings for every degree between 1 and 1000 were then obtained from these sets of power spectra through a cross-correlation of the 2\ell+1 spectra within each set. Because this cross-correlation was carried out between the frequency limits of 1800 to 4800 \muHz for each set of spectra, the resulting splitting coefficients were effectively averaged over the radial order, n, at each degree.

Due to the blending of individual p-mode spectral peaks for degrees above 200, the raw frequency splitting coefficients for all degrees between 200 and 1000 had to be corrected before an inversion could be performed. We will describe the method we adopted for correcting the raw splittings and we will present both the raw and corrected splitting coefficients. We will also present a two-dimensional inversion of the corrected coefficients. Finally, we will also demonstrate how the inclusion of the high-degree splittings allows us to obtain better estimates of the solar internal angular velocity in the shallow sub-photospheric part of the solar convection zone than have been possible in past studies which included only the splittings of the low- and intermediate-degree p-modes.

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