Surface brightness variations seen by VIRTIS on Venus Express and implications for the evolution of the Lada Terra region, Venus

Venus Express is since April 11, 2006 in orbit around Venus. VIRTIS (Visible and Infrared Thermal Imaging Spectrometer) has started only hours after orbit insertion to collect an immense and unique data set. Of special interest is the wavelength range from 1–1.5 microns which includes the ‘‘atmospheric windows’’. By averaging several hundred multi-spectral images obtained during the mission we have been able to map the surface temperatures for almost the whole southern hemisphere of Venus. Blurring in the clouds limits the spatial resolution to approximately 100 km globally. The most exciting and at the same time the most complex task is to retrieve compositional information for the surface of Venus from the hyperspectral data obtained by VIRTIS. We report here about indication for variations in the surface composition in the Lada Terra region based on brightness variations mapped fromVIRTISmeasurements and present some tentative links to the evolution of this region.