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Temporal changes in the frequencies of the solar p-mode oscillations during solar cycle 23

Published online by Cambridge University Press:  26 August 2011

E J Rhodes Jr ,
J Reiter ,
J Schou ,
T Larson ,
P Scherrer ,
J Brooks ,
P McFaddin ,
B Miller ,
J Rodriguez  and
J Yoo
E J Rhodes Jr
Affiliation:
Department of Physics & Astronomy, University of Southern California, Los Angeles, CA 90089-1342, U.S.A. Space Physics Research Element, Jet Propulsion Laboratory, Pasadena, CA 91101, U.S.A.
J Reiter
Affiliation:
Zentrum Mathematik, Technische Universität München, D-80333 Munich, Germany
J Schou
Affiliation:
HEPL 4085, Department of Physics, Stanford University, Stanford, CA 94305-4085, U.S.A.
T Larson
Affiliation:
HEPL 4085, Department of Physics, Stanford University, Stanford, CA 94305-4085, U.S.A.
P Scherrer
Affiliation:
HEPL 4085, Department of Physics, Stanford University, Stanford, CA 94305-4085, U.S.A.
J Brooks
Affiliation:
Department of Physics & Astronomy, University of Southern California, Los Angeles, CA 90089-1342, U.S.A.
P McFaddin
Affiliation:
Department of Physics & Astronomy, University of Southern California, Los Angeles, CA 90089-1342, U.S.A.
B Miller
Affiliation:
Department of Physics & Astronomy, University of Southern California, Los Angeles, CA 90089-1342, U.S.A.
J Rodriguez
Affiliation:
Department of Physics & Astronomy, University of Southern California, Los Angeles, CA 90089-1342, U.S.A.
J Yoo
Affiliation:
Department of Physics & Astronomy, University of Southern California, Los Angeles, CA 90089-1342, U.S.A.
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Abstract

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We present a study of the temporal changes in the sensitivities of the frequencies of the solar p-mode oscillations to corresponding changes in the levels of solar activity during Solar Cycle 23. From MDI and GONG++ full-disk Dopplergram three-day time series obtained between 1996 and 2008 we have computed a total of 221 sets of m-averaged power spectra for spherical harmonic degrees ranging up to 1000. We have then fit these 284 sets of m-averaged power spectra using our WMLTP fitting code and both symmetric Lorentzian profiles for the peaks as well as the asymmetric profile of Nigam and Kosovichev to obtain 568 tables of p-mode parameters. We then inter-compared these 568 tables, and we performed linear regression analyses of the differences in p-mode frequencies, widths, amplitudes, and asymmetries as functions of the differences in as many as ten different solar activity indices. From the linear regression analyses that we performed on the frequency difference data sets, we have discovered a new signature of the frequency shifts of the p-modes. Specifically, we have discovered that the temporal shifts of the solar oscillation frequencies are positively correlated with the changes in solar activity below a limiting frequency. They then become anti-correlated with the changes in activity for a range of frequencies before once again becoming positively-correlated with the activity changes at very high frequencies. We have also discovered that the two frequencies where the sensitivities of the temporal frequency shifts change sign also change in phase with the average level of solar activity.

Keywords

Sun: P-modesun: magnetic fieldsun: solar activity
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 6 , Symposium S273: The Physics of Sun and Star Spots , August 2010 , pp. 389 - 393
Copyright
Copyright © International Astronomical Union 2011

References

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