Saturday, June 03, 2006

Martian Dust Devils:



I found this animated GIF the other day while trying to locate stuff for my son about Mars.

It reminded me that I had had a conversation a few months ago with an old friend from grad school, Nilton RennĂ³, about his research work, and he told me he was busy working on the electrical properties of small eddies like these dust devils. It turns out that these things generate very intense electrical fields, and that this potential makes a large amount of dust jump off the surface, to be carried away and up into the air. His take was that these small phenomena contribute a lot more to suspended aerosols than we currently take into account.

From the NASA Phoenix mission page that has a description of his work:

Recently, Renno and his collaborators found evidence of large electric fields and non-thermal microwave emission by Martian dust devils and dust storms (Renno et al. 2003). They also showed that convective plumes and vortices play a very important role in the Earth?s aerosol budget (Renno et al. 2004, Koch and Renno 2004). Indeed, graduate student Jacquelin Koch recently showed that convective plumes and vortices are responsible for more than 20% of the terrestrial aerosol budget. In addition, Renno and his collaborators have been studying the electrification of terrestrial and Martian dust devils and storms and their effects on dust lifting and atmospheric chemistry. They have already shown that, on Mars dust electrification leads to the formation of large quantities of H2O2, a powerful oxidant. This has important implications for the chemistry of the martian soil and perhaps even to its hydrological cycle.

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