Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Height ices Mars on top

21.03.2002


Martian atmosphere churns harder in south making north wetter.


Mars: height variations lead to a wet north pole.
© NASA/JPL


The changing face of the northern polar ice cap.
© NASA/JPL



Scientists have figured out why it’s wet up north - on Mars. A new computer simulation of the martian atmosphere suggests that the planet’s geography causes differences in atmospheric circulation within the northern and southern hemispheres. These differences dump more water on the martian north pole, where it adds to the seasonal ice-cap.

Mark Richardson of the California Institute of Technology in Pasadena and John Wilson of the Geophysical Fluid Dynamics Laboratory in Princeton, New Jersey, find that the thin martian air, which is mostly carbon dioxide, rises and falls more vigorously in the southern than in the northern hemisphere1.


This difference all but disappears when the duo remove from their simulations the height variations of the martian plains. Mars’ south pole is about six kilometres higher than its north pole. By comparison, Earth’s Tibetan plateau is on average just four kilometres above sea level.

It is this height difference that makes the atmospheric circulation dissimilar in the two hemispheres, the researchers conclude. The discrepancy creates an overall south-to-north transport of water vapour as the water ice in the polar ice-caps melts during their respective summers.

Richardson and Wilson reckon that the other potential cause of the asymmetry in atmospheric circulation - the eccentricity of Mars’ orbit around the Sun -doesn’t have a major role. The shape of the orbit determines how close Mars is to the Sun around the time of the southern summer solstice. But changing this distance in the simulations doesn’t alter the asymmetry of the circulation pattern.

Hadley cells

Atmospheric circulation on Mars happens much as it does on Earth. Gases warmed at the equator rise by convection, before passing towards the poles, where they cool, sink and flow back to the equator. This creates two great lobes of circulating gas, called Hadley cells, one in each hemisphere.

The Hadley cells carry water vapour and dust picked up from the planet’s surface. Richardson and Wilson’s simulations show that Mars’ southern Hadley cell spins more vigorously. Leaking across the equator, dust and water are then borne northwards.

The Mars Global Surveyor spacecraft showed very clearly in the late 1990s that the north and south polar ice-caps are not the same. The seasonal northern ice is rough and pitted, and looks much the same all over. The southern ice, on the other hand, is sculpted by natural erosion into strange shapes, more like a permanent ice sheet.

Some of these differences may be caused by the asymmetry in circulation - although it is not yet clear how much of either ice-cap is water ice. Most of it is frozen carbon dioxide: dry ice. The Mars Odyssey spacecraft began sending data back to Earth last month, and this information is beginning to clarify how water ice is distributed over Mars.

One clear prediction of the new results concerns the formation of polar ice features called layered deposits, which are thought to consist of alternating layers of dust and ice. They have been seen at both poles, but Richardson and Wilson calculate that their growth is likely to be more rapid in the north. We haven’t watched Mars close up for long enough yet to know if this is true.

References
  1. Richardson, M. I. Wilson, R. J. A topographically forced asymmetry in the martian circulation and climate. Nature, 416, 298 - 301, (2002).


PHILIP BALL | © Nature News Service

More articles from Physics and Astronomy:

nachricht First quantum photonic circuit with electrically driven light source
27.09.2016 | Westfälische Wilhelms-Universität Münster

nachricht Australian technology installed on world’s largest single-dish radio telescope
26.09.2016 | International Centre for Radio Astronomy Research (ICRAR)

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First quantum photonic circuit with electrically driven light source

Optical quantum computers can revolutionize computer technology. A team of researchers led by scientists from Münster University and KIT now succeeded in putting a quantum optical experimental set-up onto a chip. In doing so, they have met one of the requirements for making it possible to use photonic circuits for optical quantum computers.

Optical quantum computers are what people are pinning their hopes on for tomorrow’s computer technology – whether for tap-proof data encryption, ultrafast...

Im Focus: OLED microdisplays in data glasses for improved human-machine interaction

The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP has been developing various applications for OLED microdisplays based on organic semiconductors. By integrating the capabilities of an image sensor directly into the microdisplay, eye movements can be recorded by the smart glasses and utilized for guidance and control functions, as one example. The new design will be debuted at Augmented World Expo Europe (AWE) in Berlin at Booth B25, October 18th – 19th.

“Augmented-reality” and “wearables” have become terms we encounter almost daily. Both can make daily life a little simpler and provide valuable assistance for...

Im Focus: Artificial Intelligence Helps in the Discovery of New Materials

With the help of artificial intelligence, chemists from the University of Basel in Switzerland have computed the characteristics of about two million crystals made up of four chemical elements. The researchers were able to identify 90 previously unknown thermodynamically stable crystals that can be regarded as new materials. They report on their findings in the scientific journal Physical Review Letters.

Elpasolite is a glassy, transparent, shiny and soft mineral with a cubic crystal structure. First discovered in El Paso County (Colorado, USA), it can also be...

Im Focus: Complex hardmetal tools out of the 3D printer

For the first time, Fraunhofer IKTS shows additively manufactured hardmetal tools at WorldPM 2016 in Hamburg. Mechanical, chemical as well as a high heat resistance and extreme hardness are required from tools that are used in mechanical and automotive engineering or in plastics and building materials industry. Researchers at the Fraunhofer Institute for Ceramic Technologies and Systems IKTS in Dresden managed the production of complex hardmetal tools via 3D printing in a quality that are in no way inferior to conventionally produced high-performance tools.

Fraunhofer IKTS counts decades of proven expertise in the development of hardmetals. To date, reliable cutting, drilling, pressing and stamping tools made of...

Im Focus: Launch of New Industry Working Group for Process Control in Laser Material Processing

At AKL’16, the International Laser Technology Congress held in May this year, interest in the topic of process control was greater than expected. Appropriately, the event was also used to launch the Industry Working Group for Process Control in Laser Material Processing. The group provides a forum for representatives from industry and research to initiate pre-competitive projects and discuss issues such as standards, potential cost savings and feasibility.

In the age of industry 4.0, laser technology is firmly established within manufacturing. A wide variety of laser techniques – from USP ablation and additive...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Laser use for neurosurgery and biofabrication - LaserForum 2016 focuses on medical technology

27.09.2016 | Event News

Experts from industry and academia discuss the future mobile telecommunications standard 5G

23.09.2016 | Event News

ICPE in Graz for the seventh time

20.09.2016 | Event News

 
Latest News

‘Missing link’ found in the development of bioelectronic medicines

27.09.2016 | Life Sciences

A blue stoplight to prevent runaway photosynthesis

27.09.2016 | Life Sciences

Malaysia's unique freshwater mussels in danger

27.09.2016 | Ecology, The Environment and Conservation

VideoLinks
B2B-VideoLinks
More VideoLinks >>>