Scientists manage to measure wind details of Venus

September 3rd, 2008 - 3:10 pm ICT by ANI  

Madrid, September 3 (ANI): A team led by scientists from University of the Basque Country in northern Spain has managed to measure wind details of the planet Venus.

At a height of between 45 km and 70 km above the surface, there are dense layers of sulphuric acid clouds totally covering Venus.

It was in the 1960s that scientists discovered, by means of telescopic observations, that the top level of cloud layers moved very rapidly, orbiting the planet in only four days, compared to the planet’’s own orbit of 224 days.

This phenomenon was baptized the superotation of Venus. The winds carrying these clouds travel at 360 km/h.

The various space missions that explored the planet in the 70s and 80s showed that the superotation was a permanent phenomenon and, moreover the probes that descended through its atmosphere indicated that, in a number of places, the winds decreased in speed to zero at Venuss surface.

New observations were carried out with the Venus Express mission of the European Space Agency, in orbit around Venus since April 2006.

These observations have enabled the team of scientists from the University of the Basque Country to determine in detail the global structure of the winds on Venus at its level of clouds while, at the same time, to observe unexpected changes in the wind speeds, and which will help to interpret this mysterious phenomenon.

Using images recorded by both day and night on Venus with the VIRTIS spectral camera on board the Venus Express, the Basque Country scientists have succeeded in measuring these clouds over several months and have discovered new aspects of the superotation.

Firstly, between the equator and the median latitudes of the planet, there dominates a superotation with constant winds blowing from East to West, within the clouds decreasing speed with height from 370 km/h to 180 km/h.

At these median latitudes, the winds decrease to a standstill at the pole, where an immense vortex forms.

Other aspects of the superrotation that observations with VIRTIS have made possible are that the meridional (North South) movements are very weak, about 15 km/h, and, secondly, unlike what was previously believed, the superotation appears to be not so constant over time.

We have detected fluctuations in its speed that we do not yet understand, stated the scientists.

Moreover, for the first time they have observed the solar thermal tide effect at high latitudes on Venus.

The relative movement of the Sun on the clouds and the intense heat deposited on them makes the superotation more intense at sunset than at sunrise, the scientists stated.

This study has enabled advances to be made in a precise explanation of the origin of superotation in Venusian winds as well as in the knowledge of the general circulation of planetary atmospheres. (ANI)

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