Vientos, Turbulencia y Ondas en las Nubes de Venus

Résumé : This PhD thesis consists on a study of the atmospheric dynamics of the planet Venus with data from two space missions separated in time: the Galileo mission and Venus Express. Concretely, images obtained with different wavelengths have been used to study the motions of the clouds at different vertical levels of the atmosphere, enabling to track the global atmospheric dynamics of the planet. In this thesis simultaneous measurements of the 3-dimensional structure of the winds are presented for the first time, finding and analyzing different sources of temporal variability such as the thermal waves produced by the solar insolation, global oscillations of the wind speeds and variability for periods covering from months to years. Furthermore, a study of the spatial scales of the Venusian clouds and the atmospheric turbulence have been undertaken. Frequent periodic patterns can be also seen on the lower clouds of Venus in high spatial resolution images from the instrument VIRTIS onboard Venus Express. These correspond to a type of atmospheric waves called gravity waves, and their characteristics and role in te atmospheric dynamics of Venus are analyzed at the end of the thesis.