Michael Mumma and his team are confident that they have measured local methane plumes of up to 60 parts per billion over Nili Fossae and the S.E. quadrant of the nearby Syrtis Major shield volcano.

For a good look at the Nili Fossae valleys go to http://hirise.lpl.arizona.edu/PSP_006633_2010

Thanks to UMSF (via the Titan thread) I was alerted to the fact that the Division Of Planetary Sciences of the American Astronomical Society is having its annual meeting at Cornell Uni. Go there for a feast of videoed talks with PowerPoints ranging from exoplanets to Mars to Enceldaus - http://dps08.astro.cornell.edu/AAS_WebcastSchedule_2008.html (I'm just going to have to ration myself to avoid not keeping up with work and other committments!!!).

For Michael Mumma's talk go to Session 6: Mars: Atmosphere. His talk starts around 43.45.

In 2005, his team developed a new algorithm for processing spectral data that is 10 times more senstive than the old one. Past criticism of his team's work has been that the signal to noise ratio was barely sufficient to measure methane in the 10s of ppb range with the instruments used. Mumma came across very confident in his assertion that the S/N ratio was now 'good' and that instrumental and other artifacts have effectively been reduced to an insignificant level. As far as I understand him, this is the first time that data has been presented based on the use of this new alogrithm.

One of the key findings is that methane concentrations vary in location related to the season. In Southern summer they are greatest around 60 degrees South. Yet, fascinatingly, at equinox methane is barely dectable anywhere on the planet!! In fact, the results of the work done indicate that the implied life time of methane on Mars is probably less than one year! This, in turn, indicates that there are quite unexpected breakdown pathways for this gas.

Methane concentrations are highest at Nili Fossae and Syrtis Major in Northern summer. Michael Mumma pointed out that both sites are geologically very interesting. Nili Fossae has abundant clays (phyllosilicates) and was/is rich in sub surface ice as indicated by the lobate flows around craters in the region. He thinks that methane release could be related to this. Also, the SE quadrant of Syrtis Major includes an area whose surface appears to have collapsed. This could allow methane to escape from deep within the volcano to the surface.

Nili Fossae is also interesting as it is a middle rank selection in the final 6 sites to be considered for the upcoming Mars Science Laboratory mission. It has spectacular mineralogy but is somewhat of a risky landing site. Will this discovery be enough to push it back up among the top favourites? I sure hope so!! Go to Emily's blog at the Planetary society for good links to the proposed MSL landing sites http://planetary.org/blog/article/00001650/

Michael Mumma and his team should be congratulated for their brains and persistence in following up this fascinating and important area. He mentioned that this work is yet to be published in scientific journals, but I assume it is quite ok to comment on it in a completely non commercial space like UMSF and give the team a pat on the back. (If not Doug, then please remove this post).

The big find - localized methane plumes on Mars. The big question still to answer - do they come from geochemical processes, biological processes or both? I - for one - am dying to find out!!!!

How well respected is this ground based detection of CH4 on Mars method? It seems a little black magicish to me, I mean subtracting out the absolute MESS of Earth's atmosphere to detect few PPB(!) concentrations of gas on Mars is just.....well...unbelievable. Assuming it's true though, his claimed spatial correlation of CH4 with H2O vapor would also lend as much credibility to the photolytic Sabatier-ish process atmospheric production of CH4 claim (Icarus 188, p540) as it would to bio or geo sources, the former route being the most parsimonious, imo.

It would be excellent if Mars Express could aim the Planetary Fourier Spectrometer at these localized regions each time it has the opportunity. It seems like an orbiter has a much better shot at unambiguously detecting the presence of methane. Has work like this already been done by Express?

Yep: Presentation from ESA Mars conference 2007
There are some maximums indeed, but not as sharp and strong as Mumma said. In my opinion, more important result is the correlation between water vapour abundance and methane abundance (also see this )

Pretty much not at all.

Mars, methane and mysteries
http://www.esa.int/esaCP/SEMB9OE3GXF_index_0.html

Nice update! Since the emissions are localized, spurious, and concentrated, would that strongly favor a volcanic source? If it is volcanic, shouldn't other common trace gasses, such as hydrogen sulfide and water vapor be detected?

As the article says, either way it's a huge discovery. Is there any way an infrared telecope can identify hotspots near the surface (Herschel, Spitzer)? Did Odyssey's THEMIS maps hint at anything?

Thanks for the link to the ESA article Fran. I thought that the following point was v interesting .....

" “Something is removing the methane from the atmosphere 600 times faster than the models can account for,” says Lefèvre. “Consequently, the source must be 600 times more intense than originally assumed, which is considerable even by Earth’s geological standards.” "

But there's a big caveat. See http://www.newscientist.com/article/dn1756...s-for-life.html

"Sushil Atreya of the University of Michigan ........ remains unconvinced about the calculated timescale of the destruction. "Whether the lifetime of methane is really one hour or one year is debatable," Atreya told New Scientist. "The quality of the [observational] data is not good enough to nail the lifetime that accurately."

Lefevre too admits that some of his results are extreme: "It's hard to imagine that methane could be destroyed in one hour without the other gases also being affected," he says. "Our first priority should be the confirmation of the methane variation." "

I was not aware that the PFS results were in good agreement with the ground-based results anyway; as far as I know PFS, to the extent it saw evidence for localized methane, saw it in Arabia, Elysium, and Arcadia (http://www.esa.int/esaCP/SEMAK21XDYD_Life_0.html ) whereas Mumma's plumes were in Syrtis and Nili Fossae.

I'm pretty skeptical of these results at the moment.

News story with possible Martian implications:
http://www.sciencedaily.com/releases/2009/...91104123032.htm