A new image from the High Resolution Stereo Camera (HRSC) aboard ESA’s Mars Express spacecraft shows a local dust storm with a towering cloud front, located close to the north polar ice cap of Mars. This small-scale storm, which started in April 2018, is just one of several local dust storms that have been observed on the planet in recent months.
This close-up color image of a small-scale dust storm on Mars was acquired by the HRSC instrument on ESA’s Mars Express in April 2018. Image credit: ESA / DLR / FU Berlin / CC BY-SA 3.0 IGO.
Martian dust storms occur regularly during the southern summer season when the planet is closer to the Sun along its elliptical orbit.
The enhanced solar illumination causes stronger temperature contrasts, with the resulting air movements more readily lifting dust particles from the surface — some of which measure up to about 0.01 mm in size.
“Local and regional dust storms are frequent events on Mars, but only a few of them develop into global phenomena that might persist for several months,” explained Mars Express scientists from the German Aerospace Center.
“These storms only occur every three to four Martian years, which is equivalent to approximately six to eight Earth years.”
“Although dust storms on Mars are very impressive, both visually and in terms of the intensity and duration of the rarer global events, the lower atmospheric pressure — less than one hundredth of Earth’s atmospheric pressure at the surface — means that they are less powerful than tropical storms on Earth and only reach around half the wind speed of a hurricane.”
The small, local dust storm pictured by the Mars Express orbiter is located north of Utopia Planitia, close to the ice cap at the Martian north pole.
Another, far larger storm emerged in Arabia Terra in May 2018, and within a few weeks it developed into a planet-encircling dust storm.
This global map of Mars shows a growing dust storm as of June 6, 2018. The map was produced by the Mars Color Imager (MARCI) camera on NASA’s Mars Reconnaissance Orbiter spacecraft. The blue dot indicates the approximate location of Opportunity. Image credit: NASA / JPL-Caltech / MSSS.
The current global storm is being monitored by five ESA and NASA orbiters.
“During the storm, very little sunlight reaches the Martian surface,” the researchers said.
“The solar panels on NASA’s Opportunity rover have become covered with dust, which further reduces the available power. The rover therefore automatically switched into power conservation mode and shut down communications in June 2018.”
“At the same time, the Curiosity rover remains able to explore the surface of Mars and observe the development of the storm because it is powered by a radioisotope thermoelectric generator rather than solar panels.”
Scientists expect the planet-encircling storm to weaken significantly by late autumn this year.
