[X] My Assistant

[Burmese]

More *yawn* dust devils (2)

http://marsrovers.jpl.nasa.gov/gallery/all...56P0660L0M1.JPG

Spirit would be hard pressed, I think, to make it through a day of navcam/pancam shots of the plains and -not- catch a dust devil in the act.

[Burmese]

Maybe as the season advances, the DD' start to track from different directions.

[Nirgal]

... stay tuned

[djellison]

Thats JUST how I imagined them to look - nice job

Doug

[Rxke]

Nirgal, that's uber-awesome! Thanks a million!

*scrambles to New Mars forums to bring the good news to a fellow dustdevil fan*

[RNeuhaus]

The Meridian Planum has not yet spoted any dust Evil. Have anyone ever catch sight of it?

Rodolfo

[Palomar]

Nirgal, that's uber-awesome! Thanks a million!

*scrambles to New Mars forums to bring the good news to a fellow dustdevil fan*

*Hey Rik. Looks great.

--Cindy

[Bill Harris]

There are indications that Meridiani is quite windy. The first solar panel dust cleaning event, wind movement of the heatshield mylar thermal blanket, the dust being blown away from the disturbed tracks at Purgatory dune and most recently cuttings being blown back into the RAT at the Erebus Highway stop are a few events that come to mind.

My feeling is that dust devils or whirlwinds do occur at Meridiani, but the are not _as_ visible because it is less dusty than Gusev. The "desert pavement" of the blueberries shields the underlying dust from being windblown.

In addition, we didn't start seeing dust devils at Gusev until we climbed onto the Columbia Hills and were able to look down on the dust devils contrasting against the dark Gusev Plain. Quite possibly if we did a NavCam DD survey of the sky at Meridiani and enhanced the images we could spot a DD.

That's my take...

--Bill

[RNeuhaus]

What are the influences to cause a dust evil?

Now, Mars is on Late South Hemisphere Spring (267.3 degrees), The solciticio (270 degrees start the first day of Winter in the northern hemisphere and the first day of Summer in southern hemisphere). Now we are close to Summer which I think it is around August 20 since I have seen this data from a previous posting).

The Oppys' location place is 2 grades South of Equatorial, and Spirit's location place is 14.7 grades South of Equatorial.

My supposition is about why the Gusev Crater has most often Dust Devil because of :

1) The Meridian Planum is a flat zone and the wind direction is most constant. That makes more difficult to create a Dust Devil Winds.

2) The Gusev inside crater, the wind direction is not so constant as the MP and it has more windwhirls due to the mountain basin zone.

3) The Meridian Planum position is ubicated a slight closer to Equatorial line than the ones of Gusev's Crater. The zone of Gusev must be hotter than the MP zone. The hotter, the winder is.

4) (Bill's suggestion) The Spirit position is higher than the ones of Oppys. That helps to spot easier any dust devil.

5) (Bill's suggestion) The Gusev place is dustier than MP ones. The windwhirl is most visible if there is more dust.

6) (Bill's suggestion) The visual constrast on Dust Devil is greater if it is against a land or mountain. Hence the Spirit's place has the advantage.

The conclusion is that Spirit needs greater luck than Oppy to be washed by a cold wind...since Oppy takes off the dust in almost everyday and Spirit, still very dirty and hungry and begging for coming any dust devil, to be cleaned.

I still have doubts on it since I am not a meteorologist but I like to understand it...

Click here for more information about Martian Weather

Rodolfo

[Bob Shaw]

There are indications that Meridiani is quite windy.  The first solar panel dust cleaning event, wind movement of the heatshield mylar thermal blanket...

--Bill

Bill:

I must have missed that! Can anyone point to the pictures which bear this out? Or are we just talking mylar bunnies at mission start, which may have moved under a variety of influences...

Bob Shaw

[RNeuhaus]

I remember that the past time, after visiting the heatshield, the Oppy's solar power was cleared suddenly. The invisible dust devil must have blown on it or it was a some kind of burst/gust of wind?

Rodolfo

[um3k]

I have an idea for color dust devil images:
Take L2 and R1 or L7 and R2 images simultaneously. The dust devils are far enough away that the parallax is negligible. Voila, dust devils in color!

[helvick]

I remember that the past time, after visiting the heatshield, the Oppy's solar power was cleared suddenly. The invisible dust devil must have blown on it or it was a some kind of  burst/gust of wind?

Rodolfo

There were four small (5% increase in power or so) "unexplained" cleaning events prior to Sol 310 that Jim Eriksson referred to in this New Scientist article. At the time Spirit had been more or less steadily losing power generating capability in line with expectations. On sol 310 the power jump was definitely attributed to a wind cleaning event but it wasn't captured on any images AFAIK.

[Nirgal]

I have an idea for color dust devil images:
Take L2 and R1 or L7 and R2 images simultaneously. The dust devils are far enough away that the parallax is negligible. Voila, dust devils in color!

this won't work because of the parallaxe (offset angle) between Left and Right camera eye ... so we can't match L2/R1 or L7/R2 pairs pixel-per-pixel

However, I remember at least one "true" color dust devil image taken with the pancam (unfortunately I don't remember who originally posted it (Nico ?, Daniel ? ...
just correct me if I'm wrong)



This is also one of the "true color" reference images I used for my hand colorization of the sol568 movie frame above ... so I hope my colors are not
too far off ... and isn't it also an advantage of not having true color photos of those devils: to leave a little bit room for our own color imagination

[Nirgal]

forgot to mention that in the image above the actual dust devil is
only persent in one of the frames used for the multi-filter composite
(due to the dd movement) ... so actually it's more like a monochromatic dust devil against a true color background.

[Bill Harris]

I must have missed that! Can anyone point to the pictures which bear this out? Or are we just talking mylar bunnies at mission start, which may have moved under a variety of influences...

The two major discussions on the heatshield were:

http://www.unmannedspaceflight.com/index.php?showtopic=577

http://www.unmannedspaceflight.com/index.php?showtopic=561

with a lot of disccussion of the wind movement.

And Doug Ellison's own image of a piece of the heatshiled flapping in the breeze hs_wind.gif , appended below.


--Bill