The winds of Venus reach their maximum precision

2008/10/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Astrofisika

The UPV Planetary Science Group has analysed the winds of the cloud layers of Venus with the new data provided by the Venus Express probe. Basque researchers have determined the general structure of the layers and have observed unexpected changes in the speed of these layers. The data collected will help to understand a mysterious phenomenon: why the atmosphere of Venus rotates much faster than the planet itself - called superrotation.

The VIRTIS spectral camera of the Venus Express probe has collected data, images taken on the day and night of Venus. Scientists at UPV-EHU have been able to measure the movements of clouds reflected in the images for a few months and have discovered new aspects of superrotation. To begin with, they have seen that between the equator of the planet and the average latitudes predominates a superrotation with stable wind. The wind blows from east to west and, in general, loses force inside the clouds as it loses height: it drops from 370 km/h to 180 km/h. From these middle latitudes, the wind loses strength until it reaches the pole and disappears. There, at the pole, a large swirl is created.

Other aspects that have been determined thanks to the observations made with the VIRTIS camera are, on the one hand, the movements from North to South are very weak, about 15 km/h, and, on the other hand, against what was previously thought, the superrotation does not seem so stable in time. In fact, the missions that studied Venus in the 1970s and 1980s considered superrotation as a stable phenomenon.

This study will explain the origin of the superrotation of the wind in Venus and, in general, advance in the knowledge of the atmospheric circulation of the planets.

All these data have been published in the journal Geophysical Research Setter. This journal, published by the American Geophysical Union (DUGU), is the most influential in this field of research.