The Venus Emissivity Mapper - Investigating the Atmospheric Structure and Dynamics of Venus' Polar Region

Abstract

The Venus Emissivity Mapper (VEM) is the first flight instrument specially designed to map the surface of Venus using the narrow atmospheric windows around 1 micron. VEM is proposed for the European Space Agency's M5/EnVision proposal in combination with a high-resolution radar mapper (see Abstract #1937). Mapping of Venus with VEx/VIRTIS using the 1.02 micron thermal emission band can be viewed as a proof-of-concept for an orbital remote sensing approach to surface composition and weathering studies for Venus. Thermal brightness on Venus' night side is mainly modulated by the lower clouds, imaged at 2.3 micron by the Akatsuki IR2 camera. Thanks to the circular polar orbit geometry of M5/EnVision, VEM has the unique capability to (1) better constrain the microphysics of the lower cloud particles in three spectral bands at 1.195, 1.310 and 1.510 micron at a spatial resolution of ~10 km, and (2) investigate short-timescale cloud dynamics and thus local wind speeds by tracking cloud features in both polar regions.