Tidal torque applied to the atmosphere of Earth (left panel) and Venus (right panel) by the thermal semidiurnal tide and its components as functions of the reduced frequency χ = (Ω−n_orb) /n_orb (horizontal axis). The forcings consist of academic quadrupolar perturbations expressed as and with U₂ = −0.985 m² s^-2 and J₂ = 1.0 × 10^-2 m² s^-3 for the Earth and U₂ = −2.349 m² s^-2 and J₂ = 1.0 × 10^-4 m² s^-3 for Venus. Labels T, H, and V refer to the total response and its horizontal and vertical components, respectively (we note that ). The label CL01 refers to the model by Correia & Laskar (2001), given by Eq. (175).