I am trying to calculate co and quad spectra for meteorological variables in order to spectrally examine momentum and energy fluxes. I noticed that the spec.pgram function returns power curves for both individual variables as well as coherence and phase information, but nothing about the co/quad spectrum. Does anyone have any experience with this and know of a way to back the cross-spectra out of this information or know of another package? Thanks Bryan -- Bryan Woods Dept. of Geology & Geophysics Yale University, KGL 234 210 Whitney Ave New Haven, CT 06511 978.726.3462 (cell) 203.432.3134 (fax) 203.404.3365 (home)