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Live Dust Devil?
azstrummer
post Mar 10 2005, 11:17 PM
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Man, this looks an awful lot like a dust devil in the distance. What do you think?

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Bill Harris
post Jun 19 2005, 03:42 PM
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Dust devil activity should increase since Mars is at or near perihelion and the southern solstice. I figure that there is a lag time between the maximum insolation and the DD activity so later this Summer ought to be interesting.

--Bill


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dvandorn
post Jun 19 2005, 07:15 PM
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Remember, we have a certain baseline of observations from the earliest part of the mission. Spirit landed in late summer/early fall, local time, correct? And the DD activity at that time was minimal -- we never saw much in the way of them until we were well into the following spring.

We also saw the begining of DD season in early spring, and it seems to have peaked and has been trending down for a week or two, now.

I guess what I'm wondering is whether higher levels of insolation will, in fact, result in the formation of even more DDs? I think it's possible that the process of DD formation might not be directly related to insolation levels.

I also find it fascinating that DD formation seems almost more related to terrestrial tornado formation than simple terrestrial dust devil formation. Have you noticed how many of the larger DDs seem to start out with two, and sometimes more, small funnels dancing around the area in which the larger funnel shortly appears? This same fundamental observation has recently been made of terrestrial tornadoes -- that small, transient "whirlpools" dance and rotate around a larger low-pressure dip, "spinning up" the main funnel.

I think there are hints that we're seeing the same basic process in the Martian DDs, too.

Finally, I'll point out that whirlpool activity in fluid gas is driven more by pressure deltas than by temperature deltas, and that the Martian atmosphere's thinness gives other factors (including topography) more impact on pressure deltas than heating effects do. And observations from Viking, Pathfinder, MGS, MO, MEX and the MERs all show that local heating of the air by ground re-emission only strongly affects the air temperature for a few feet above the ground. Thermal homogenization occurs very, very low in the atmosphere. Topography, affecting air pressure directly and controlling most of the fine detail of lower atmospheric heating, seems to be the largest factor in local weather events. (Just look at how DD tracks are mostly isolated to very small patches, usually just off-center from the centers of large craters.)

-the other Doug


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Bob Shaw
post Jun 19 2005, 09:01 PM
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I wonder whether the view from on high helps to find the Dust Devils for us - perhaps we've been seeing more because we have a good view out to the plain, and not because there were fewer of them earlier in the Martian year.


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Posts in this topic
- azstrummer   Live Dust Devil?   Mar 10 2005, 11:17 PM
- - Bill Harris   Dust devil activity should increase since Mars is ...   Jun 19 2005, 03:42 PM
|- - dvandorn   Remember, we have a certain baseline of observatio...   Jun 19 2005, 07:15 PM
|- - Bob Shaw   I wonder whether the view from on high helps to fi...   Jun 19 2005, 09:01 PM
- - ilbasso   I agree with Bob. There may be some seasonality t...   Jun 19 2005, 10:32 PM
|- - wyogold   QUOTE (ilbasso @ Jun 19 2005, 10:32 PM)I agre...   Jun 20 2005, 04:24 AM
- - Bill Harris   I'm in agreement with Bob and ilbasso; I think...   Jun 20 2005, 02:24 AM
- - edstrick   When there's a major "dump" of dust ...   Jun 20 2005, 04:37 AM
- - Phil Stooke   There is a new 'month in review' PDF file ...   Jun 21 2005, 05:44 PM
- - Tman   Daniel and/or Michael here we go!!! A...   Jun 28 2005, 10:16 AM
|- - jaredGalen   It looks like it had quite a cleaning effect on th...   Jun 28 2005, 12:57 PM
||- - Jeff7   QUOTE (jaredGalen @ Jun 28 2005, 07:57 AM)It ...   Jun 29 2005, 02:46 PM
|- - MichaelT   QUOTE (Tman @ Jun 28 2005, 10:16 AM)Daniel an...   Jun 28 2005, 02:19 PM
- - Decepticon   Where is this PDF file?   Jun 28 2005, 12:10 PM
- - Bill Harris   The "Month in Review" files are at the N...   Jun 28 2005, 12:20 PM
- - Nix   Nice one! sol 527 dust-devil Nico   Jun 28 2005, 02:48 PM
- - Tman   It seems it's a pretty long tube-like DD at th...   Jun 28 2005, 03:25 PM
- - alan   Dust devil paths clipped from HUGE pdf file   Jun 28 2005, 04:49 PM
|- - Nirgal   Wow NIX: nice colors !! this is definitel...   Jun 28 2005, 08:16 PM
- - Nix   Thanks, color to wavelength conversion in PS, leve...   Jun 28 2005, 09:33 PM
- - slinted   I've been playing around with several differen...   Jun 28 2005, 10:59 PM
|- - tfisher   QUOTE (slinted @ Jun 28 2005, 06:59 PM) Wow...   Jun 29 2005, 03:01 PM
- - CosmicRocker   That's an interesting image. I can convince m...   Jun 29 2005, 04:40 AM
- - glennwsmith   Re your newest enhancement, slinted, you've do...   Jun 29 2005, 07:49 AM
- - slinted   Sol 530 brings us another very active dust devil m...   Jun 30 2005, 11:32 PM
|- - ustrax   Mamma mia!!! http://qt.exploratorium....   Jul 1 2005, 11:59 AM
|- - dvandorn   That looks less like a dust devil and more like a ...   Jul 1 2005, 12:04 PM
|- - ustrax   QUOTE (ustrax @ Jul 1 2005, 11:59 AM)Mamma mi...   Jul 6 2005, 04:35 PM
|- - jaredGalen   Tried to enhance the sequence a bit. Looks like on...   Jul 6 2005, 05:12 PM
- - djellison   RE: Live Dust Devil?   Jul 1 2005, 12:07 PM
|- - mhoward   New Spirit images (sol 532, 533) have appeared on ...   Jul 5 2005, 11:47 PM
- - slinted   Dr. Lemmon is describing the full 21 frame movie o...   Jul 5 2005, 11:46 PM
- - alan   This one is between Spirit and West Spur http://ma...   Jul 6 2005, 03:13 AM
- - Sunspot   Has the dust cleared from the atmosphere a little?...   Jul 6 2005, 09:09 AM
|- - Tman   QUOTE (Sunspot @ Jul 6 2005, 11:09 AM)Has the...   Jul 8 2005, 10:49 AM
- - BruceMoomaw   We now have the neatest set of dust devil movies y...   Jul 11 2005, 11:16 PM
- - Bob Shaw   Interesting comments on electric dust devils... h...   Jul 16 2005, 03:20 PM
- - RNeuhaus   QUOTE (Bob Shaw @ Jul 16 2005, 10:20 AM)Inter...   Jul 18 2005, 07:33 PM
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