Geologic Analysis of the Surface Thermal Emission Images taken by the VMC Camera, Venus Express

Abstract

Introduction. The Venus Monitoring Camera (VMC) onboard Venus Express takes images in 4 channels, one of which is centered at 1.01 μm. When the camera looks at the night side of Venus, this channel registers thermal emission from the planet surface from mid-southern to mid-northern latitudes [1]. Due to scattering of the emitted radiation in the atmosphere and the cloud layer, the effective spatial resolution in the surface images is ~50 km. Thus, modeling the atmospheric blurring is essential for this work. Here we report results of preliminary analysis of some VMC 1-μm images. Intensity of the surface thermal emission at 1 μm depends strongly on its temperature and thus on surface elevation as well as on surface emissivity and cloud opacity. But emissivity of the surface material depends also on surface texture and mineralogy so the image analysis can provide an information on these parameters. Also, if there is an ongoing volcanic eruption in the camera field of view, it might be noticed on the images.