Gong p-mode frequency changes with solar activity

Citation
A. Bhatnagar et al., Gong p-mode frequency changes with solar activity, ASTROPHYS J, 521(2), 1999, pp. 885-888
Citations number
16
Categorie Soggetti
Space Sciences
Journal title
ASTROPHYSICAL JOURNAL
ISSN journal
0004637X → ACNP
Volume
521
Issue
2
Year of publication
1999
Part
1
Pages
885 - 888
Database
ISI
SICI code
0004-637X(19990820)521:2<885:GPFCWS>2.0.ZU;2-F
Abstract
We present a correlation analysis of GONG p-mode frequencies with nine sola r activity indices for the period from 1995 August to 1997 August. This stu dy includes spherical harmonic degrees in the range 2-150 and the frequency range of 1500-3500 mu HZ. Using three statistical tests, the measured mean frequency shifts show strong to good correlation with activity indices. A decrease of 0.06 mu HZ in frequency during the descending phase of solar cy cle 22 and an increase of 0.04 mu Hz in the ascending phase of solar cycle 23 are observed. These results provide the first evidence for change in p-m ode frequencies around the declining phase of cycle 22 and the beginning of new cycle 23. This analysis further confirms that the temporal behavior of the solar frequency shifts closely follow the phase of the solar activity cycle.