The spatiotemporal dynamics of the solar photosphere is studied by performing a proper orthogonal decomposition (POD) of line of sight velocity fields computed from high resolution data coming from the MDI/SOHO instrument. Using this technique, we are able to identify and characterize the different dynamical regimes acting in the system. Low-frequency oscillations, with frequencies in the range $20–130\mu \mathrm{Hz}$, dominate the most energetic POD modes (excluding solar rotation), and are characterized by spatial patterns with typical scales of about 3 Mm. Patterns with larger typical scales of $\simeq 10\mathrm{Mm}$, are associated to $p$-modes oscillations at frequencies of about $3000\mu \mathrm{Hz}$.

• Received 24 March 2005

DOI:https://doi.org/10.1103/PhysRevLett.95.061102