Simulation Study on Passive Microwave Remote Sensing of the Venusian Lower Atmosphere

 The existing measurements of the lower atmosphere provided little information about the spatiotemporal distributions and variations of temperature and sulfur compounds profiles. An improved understanding of temperature and sulfur compounds in the Venusian lower atmosphere is required to investigate the mechanisms which maintain the atmospheric super-rotation, the surface-atmosphere interactions, and the origin and evolution of the Venusian atmosphere and climate. In the present study, we demonstrate that a passive microwave sounder placed in low Venus orbit could provide the required high-precision, high-resolution and vertically-resolved observations of temperature, sulfur dioxide (SO₂) and gaseous sulfuric acid (H₂SO₄(g)). By model simulations, the frequency channel selection and performance simulation for the sounder are completed. The simulation results show that temperature can be measured from the Venus surface to ~61 km with a precision of 1-3.5 K and a vertical resolution of 6-15 km. Precision of 10-35% is expected for SO₂ in the ~12-64 km altitude range and with a vertical resolution of 8-19 km. H₂SO₄(g) can be measured in the altitude range ~36-54 km with a precision of 10-30% and a vertical resolution of 6-13 km.