Decorrelation Time of Fourier modes in the Spectrum of Solar Background Velocity Fields

We calculate the power-energy spectrum of time series of SOHO/MDI line-of sight high resolution Doppler images near disk center. While the spatial spectrum presents velocity features at characteristic scales and not a cascade in wavenumber space, we investigate the extent to which it is still possible to describe in terms of a scaling exponent the properties of the decorrelation time for each Fourier mode as a function of wavelength. We explore the sensitivity of the result to different methods for removing the contribution of the p-modes to the spectrum.