Transmission of waves as function of wave period; a) with infinite spectral resolution for IGR (dotted) and after applying the convolution with spectrometer function and filtering; solid: for GR, dashed: for IGR; thin: for waves with amplitudes independent of height, thick: for waves with exponentially increasing amplitude; b) comparison of transmission for waves with exponentially increasing amplitude and with adopted inclination θ of 0°, 30°, and 45°; solid: GR, dashed: IGR.