Temporal evolution of f-mode frequencies and radius

We have analysed temporal evolution in centroid frequencies and splitting coefficients of solar f-modes obtained from MDI/SOHO. The data were divided into 20 sets covering a period from May 1, 1996 to August 31, 2000. The variation in frequencies is estimated to be 68 nHz over the period of four years which includes the rapidly rising phase of the solar cycle 23. This change is much smaller than that observed for p-mode frequencies. It is also noticed that the f-mode frequencies appear to be weakly correlated with solar activity indices as compared to the p-mode frequencies. We have also inferred the relative change in the solar radii and notice a 1 year periodicity which may be associated with the solar cycle variation.