Mars Express witnesses dust storm on the planet

December 12th, 2007 - 4:50 pm ICT by admin  

Paris, Dec 12 (ANI): New observations from Mars Express, a Mars exploration mission of the European Space Agency (ESA), have indicated the occurrence of a dust storm that engulfed the Red Planet recently.

This dust storm, which takes place on the planet on a regular basis, contributed to a temporary warming effect around Mars, which raised the temperature of the atmosphere by around 20-30 deg C. However, this resulted in a drop in the surface temperature of the planet.

Planetary scientists watched the latest dust storm take shape at the end of June. By mid July it had covered the Red Planet, dispersing gradually over the next few months.

The Planetary Fourier Spectrometer (PFS) instrument was able to work throughout the event and has gained new insights into the effects of the dust storms on the atmosphere of Mars.

“Once the atmosphere becomes full of dust, only 20% of the solar radiation can reach the surface of the planet,” said Vittorio Formisano, principal investigator of the PFS instrument.

The dust absorbs the solar radiation which directly heats the atmosphere, creating a strong warming effect.

This year, PFS saw the temperature of the Martian atmosphere rise by between 20-30 deg C. As the atmosphere heats up, the atmosphere inflates around the planet.

According to Formisano, this increase was probably by about 20 km and hopes that a fuller analysis of the PFS data will give a precise figure.

PFS determines the composition of the Martian atmosphere from both the wavelengths of sunlight absorbed by the various molecules in the atmosphere and from the infrared radiation they absorb and emit. It collects infrared radiation in the range of 1.245 micrometres (microns).

But, there is still a lot to understand about Martian dust storms.

They begin during summer in Mars’s southern hemisphere. Southern summer is hotter than the northern summer because Mars’s orbit is elliptical and draws the planet closer to the Sun during southern summer than during northern summer.

The Hellas Basin obviously plays a very important role as the dust storms usually begin in its vicinity. Hellas is a vast impact structure, 9 km deep and about 2300 km across. It is so large that it disrupts the circulation of the atmosphere.

“How the dust propagates into the whole atmosphere is still a complete mystery,” said Formisano. (ANI)

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