Imaginary part of the component of surface pressure variations as a function of the normalized forcing frequency in the reference case (a = a_Venus and p_s = 10 bar). Top left panel: spectrum over the high-frequency range (− 300 < ω < 300) in linear scales. Top right panel: spectrum over the low-frequency range (− 30 < ω < 30) in linear scales. Bottom left panel: spectrum in logarithmic scales (for ω > 0). Numerical results obtained with GCM simulations are plotted (grey points), as well as the interpolating function f_GCM (grey solid line), the odd and even functions of σ defined by Eqs. (6) and (8) (black and purple solid line, respectively), the function derived from the abinitio analytical model and given by Eqs. (12) and (13) (orange dashed line), its Maxwell-like approximation given by Eq. (17) (red dotted line), and the parametrized function given by Eq. (26) (blue dashed line).