We present an analysis of the spectral characteristics of the vertical motion field observed with the European incoherent scatter VHF radar near the summer mesopause. The data were collected in a mode permitting very precise measurements of vertical velocities with very high spatial and temporal resolution. High measurement accuracies resulted in broad spectral sensitivity extending well into acoustic wave frequencies. High spatial resolution in addition provided sensitivity to more than a decade of vertical wavenumbers. Mean frequency spectra exhibit a rapid decrease in amplitude near the buoyancy frequency, suggesting weak Doppler shifting conditions. Frequency spectra also display high vertical coherence and variable noise levels, implying coherent motions at large scales and geophysical modulation of velocity estimates at smaller spatial and larger temporal scales. Vertical wavenumber spectra reveal a sharp contrast between ducted and vertically propagating motion fields. Spectra of propagating motions exhibit a steep slope consistent with vertical wavenumber spectra of horizontal motions. A separable model spectrum is seen to be consistent with the observed vertical velocity characteristics and spectra. ¿ American Geophysical Union 1995