I've taken the tabulated TAU data from the analysts notebook just to have a little play around...

http://mer.rlproject.com/mer_tau.gif

Ignore the trend lines - they're essentially useless - but - whilst they both follow the same post-dust-storm down trend ( which, by the end of the 0-90 sol data we have available isnt levelling off ) Spirit has a strange peak at around sol 50-60 (about the time it was approaching Bonneville) - Anyone know of any local phenom. that might have caused something like that. A dust devil might have chucked something up for an afternoon, maybe for a sol or so - but not a 3 or 4 sol increase followed by a 3 or 4 sol decrease.

There's other data within the released sets but I'm not too confident as to how it might be relevant to opacity per-se

http://anserver1.eprsl.wustl.edu/anteam/mera/mera.htm

CC'd to Alex's Plan.Sci. YG.

Doug