[PCG22-P04] Investigation of Venusian upper troposphere using millimeter-wave continuum emission
Keywords:Venus, atmosphere, ALMA
A new approach to the upper troposphere of Venus is proposed by using millimeter-wave (microwave) observations. At the microwave region, the main opacity source in the Venusian atmosphere is the collision induced absorption (CIA) of CO2, whereas the cloud opacity becomes almost negligible due to relatively long wavelength of observations compared to the sizes of cloud particles (~order of several microns). The CO2 CIA reduces its absorption intensity with increasing the wavelength at millimeter-wave domain (and becomes almost transparent at radio frequencies). The radiative transfer calculation of the CO2 CIA opacity indicates that the thermal emission originated from the altitudes of ~40–60 km can be observed at millimeter-wave of λ = 3 - 4 mm (frequency of ~60 – 100 GHz) — which is the operation wavelength of the currently under development ALMA Band-2 receiver.
This study reviews potential scientific topics that can be investigated with the millimeter-wave continuum emission from Venus atmosphere, and presents feasibility study of the application of ALMA – Band 2 receiver in future Venus observations.