Temperature map of the south polar vortex

This temperature map of the south polar vortex was made with data from the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) on board ESA’s Venus Express.

The image, taken on both night and day sides, shows the colour-coded brightness temperature (in Kelvin) of the dipole and of the cold-collar region at 5.05 micrometres.

The level curves in the image are the real atmospheric temperatures retrieved from VIRTIS from the atmospheric layer at about 60-km altitude.

The warmer region corresponds to the ellipse containing the dipole where the highest temperature (250K) is observed in the centre of rotation of the dipole itself, on the left side. The coldest region of the polar collar with temperatures of about 210K is registered on the right side, at the morning
terminator.

The right graph shows the vertical atmospheric temperature profile in two different regions. The green curve corresponds to the green spot on the left image, inside the polar collar region. The red curve corresponds to the red spot inside the dipole.

At this altitude the temperature of the polar region is the highest on the whole planet. Also, the most prominent turbulence is observed here.

This image, taken at around midnight local time, at 1.7-micrometres, reveals what is present at an altitude of 45-50 km in the south polar region. It is possible to see that the cloud curtain is very thick and opaque.

The imaged area is located between 40º south (bottom of the image) and 80º south (top) image top.