Series of high resolution spectrograms taken simultaneously in three spectral regions were recorded with a lambda meter and subjected to a statistical analysis of the fluctuations of Doppler shift and brightness.
(1) The 5-rain oscillations are cenfu'med to be 'evanescent' waves. Their horizontal wavelengths range from 9" to 15" and probably still larger values.
(2) Horizontal sound waves (Lamb waves) are only of minor importance in the photospheric velocity field.
(3) Vertically propagating sound waves are observed and are used to establish a geometrical height scale. The horizontal wave numbers of these sound waves cover a wide range including the scales of both the 5 rain oscillations and the granular convection.
(4) The inversion of the granular brightness pattern at higher photospheric levels is confirmed for wavenumbers smaller than 8 Mm 1. At k ~, 10 Mm 1, however, the correlation of brightness and blue shift observed in the photosphere holds also in lines originating as high as Na I(DI). This statistical result is related to structures directly visible in spectrograms. * Mitteilung aus dem Fraunhofer Iustitut Nr. 131.