Solar oscillation parameters, such as the frequency, are usually estimated by fitting the mode profile in the velocity (V) power spectrum. In this paper, the solar oscillation parameters are derived by simultaneously fitting four observational spectra: V and I(intensity) power, I―V phase difference, and I―V coherence using the model of Severino et al. that contains several background components. We show that this model reproduces the observed spectra for l = 15-50 using Global Oscillation Network Group (GONG) data. A study of the model parameters as a function of frequency shows the well-known behavior of the mode amplitude and width. Comparing the oscillation parameters using the multispectral fitting and the V power spectrum alone with an asymmetric profile shows that the oscillation frequency differs by at most 0.2 μHz below 3 mHz but that the background components are needed to adequately describe the spectrum at higher frequencies. The background amplitudes and phases provide information about the solar oscillation excitation mechanism. For example, the coherent correlated background might be associated with the darkening observed in the intergranular lane at the beginning of the seismic event, while the coherent uncorrelated component might be related to seismic events unable to excite the 5 minute oscillations.
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