Dust Storm Options

[sranderson]

Spaceweather (www.spaceweather.com) is reporting a dust storm on Mars visible in amateur telescopes. Hope we don't get too much dust-fall on the solar panels....

[Bill Harris]

This didn't quite show what I'd hoped it would, but here it is for your FWIW file...

Here is a montage of four Forward Hazcam images from Sols 627, 626, 624 and 616 that semi-shows a build-up of dust in the atmosphere, but not conclusively.

--Bill

[Ames]

The latest hazcam pictures show the shadow as being sharp - as I would expect.
BUT the shadowed zone is lighter indicating that there is more "ambient" light.

Think of the sky here on earth and compare the shadows on a cloudless day:
1) in a smoggy city (say LA)
2) in mountains.
Both have crisp edges but the contrast in the mountains is much higher.

The latest rear hazcam images definately show a reduced shadow contrast.

Nick

[tedstryk]

I imaging the stretching of the "raws" wrecks havoc on our ability to determine how much the brightness of the seen is effected.

[helvick]

I imaging the stretching of the "raws" wrecks havoc on our ability to determine how much the brightness of the seen is effected.

True but there are a couple of things to note that can give us something to work on.
Tau=5. There will be no clear shadows at all, at noon the diffuse illumination will be about 2 orders of magnitude more intense than direct beam illumination and it's even more extreme when the solar elevation is low.
Tau=2, There will be faint shadows, diffuse lighting at midday is about 5x the intensity of the direct beam, and once again that rises significantly further from noon.
Tau=1, Clear shadows are visible but shaded areas are well illuminated. Diffuse light is about 20% higher than direct at noon. Overall daily diffuse insolation is about 80% more than direct beam.
Tau=0.5, Crisp shadows and shaded areas are noticably dark. Direct beam is ~70% more than diffuse light at noon. Total daily beam insolation is abotu 20% more than direct beam.
Tau=0.1, Extremely well defined shadows. Beam lighting is ~10x the intensity of diffuse at noon.

Things get a bit fuzzy very early\late in the day when tau is above ~0.2 as direct beam falls off rapidly at low sun angles while diffuse light falls off pretty slowly.