I think you are correct Fred. This storm is not over yet. It could last a few more weeks. These peaks keep rolling into new peaks for other areas of Mars. We don't how bad this will get. It appears to becoming a global storm. Yet as far as we know, it could start to settle down tomorrow.

I'm glad that the tau at Meridiani appears to be stable; but who knows what will happen next?

On that gif the change in light diffusion in the shadow on the antenna is really obvious.

What Viking and Mariner 9 saw was that storm activity keeps popping up and regenerating as long as there are relatively clearer parts of the atmosphere.

Once circulation and recirculation of storm-dust has pretty much uniformly filled the atmosphere with some relatively uniform few tau of dust, temperature differences drop below levels needed to churn up more dust. The storm then transitions to a decay phase, with an atmospheric dust half life of something like a couple weeks. Maybe that's equivalent to one tau's drop per two weeks..

Viking had two dust storms in one year -- most unusual -- the second one started just after the decay of the first storm got dust levels down to maybe about tau=1.. the levels present before the first storm really started.

As I recall, the first storm was pre-perihelion.. late spring.. the second was in summer.

talking of popping up again...

I've added a few bits - can you tell I was bored on the train yesterday

Hi Doug
These graphs have been very helpful to get an idea of whats going on.
Thanks for finding Marks data so quickly and putting it on the site, nice new touches too but perhaps there should be more orange (dust) on the top half of the graph to match the Tau going up.

Roy

Well, according to Mark Lemmon's site tau is now 3.3 for Spirit. Same as Oppy. Maybe it will stabilize around this value then.

Everybody says Martian dust storms begin in the summer. But what time of year IS it anyway? The official MER-site and the MMB both have very nice martian clocks, but no calendar!
Is it 'June', 'July' or 'August' now? And is there a comparison somewhere on the net with the 1971 and 2001 storms? In which 'months' did those storms start and decay?

The southern summer solstice was last week.

For a Mars calendar/clock, I like Mars24:

http://www.giss.nasa.gov/tools/mars24/

--Greg

And here's a table showing some past and future Mars seasonal dates. I have always intended to add some past ones going back to Mariner days, but never got around to sitting down with Mars24 and plugging dates in to find all the solstices and equinoxes.

http://planetary.org/explore/topics/mars/calendar.html

The Mars dust storm season begins just after perihelion at around Ls = 260°, wich is 10° (that is, 1/36 of a year or 1/3 "month", whatever that means for Mars) before the summer solstice.

--Emily

Look at those drastic differences in the tracks after the new drive!

http://qt.exploratorium.edu/mars/opportuni...RZP2571L2M1.JPG

That's amazing. Does anyone know which days those tracks are from? I know the clear ones were just made.

Some updated numbers in the latest Oppy update:Also, some more details to add to the confusion about how much power Oppy needs to survive:

Before anyone worries unduly, we should remind everyone that the news updates usually lag behind. Sol 1225 was the peak tau (as far as we've been told). It's now early on sol 1234 (heh, neat), and the tau is lower than that, unless it's spiked back up in the last two sols.

Actually....from mark lemmon's site:

Sol 1233B: Opacity B1233 was 3.8 but it got above 4 during the sol.

Continues to rise for both Oppy and Spirit. Unfortunately.

D'oh. Okay, I guess it has spiked back up. How unfortunate.

Yeah, mhoward, I could have said "some updated old numbers".

Speaking of Lemmon's site, he also writes:What the heck does he mean by "lifting"? Lifting of dust as the storm subsides? It's not exactly subsiding! He says "fast dd movies" - does that mean they're looking for short time scale phenomena? Gusts of wind perhaps?? Any other ideas?

Yeah, I saw those frames come down today and wondered, "are they doing DD movies at Meridiani?" I suspect all of the frames are not down, but some looked to be fast, and others were many seconds apart. We at least seem to have parts of two movies so far.

I thought I noticed some subtle, local brightness variations in the sky among the available raw navcams. Maybe some of our "above the horizon" image magicians can find evidence of dust being lifted from the ground. That's what I think was meant by lifting.

The storm is certainly not subsiding yet. Meridiani and Gusev are experiencing new peaks. Searching for some good news, it sounds as if the rovers have plans for tau values around 5,

New record for Opportunity on B1234 of 4.2. Much kudos to Mark for keeping the figures updated despite being involved in a Phoenix ORT.

Doug

Oh my...not good. I searched in vain for the latest amateur Mars obs of this storm...anybody have any updates? This data suggests regional enrichment.

Damian Peach has put a few up at the BAA website ( www.britastro.org )

Doug

I also found this site:

http://elvis.rowan.edu/marswatch/news.php

Click on images on the left.

Some new info on the HiRise blog. From July 11th:

http://hirise.lpl.arizona.edu/HiBlog/?p=92#more-92

Some HiLights:

At this point, the storm is considered a "hemispherical event," meaning it's mainly affecting "only" half of the planet (the southern hemisphere, in this case). We have our fingers crossed that this will not expand and become a global event like the 2001 dust storm.

The CRISM instrument can measure the composition of the dust, for example, so we've helped them acquire extra images by canceling a number of our own images that would have been obstructed by the dust anyway.

While we wait to see what the dust does, our Targeting Specialists are scrambling to cancel observations and figure out where to take a chance and try imaging.

From New Scientist: http://space.newscientist.com/article/dn12...ect-rovers.html

I'm still a bit worried. As I said before it all has to fall down and it won't be any less opaque when it does. If it's 'hemispheric' as opposed to regional then there is no escape from the debris. We will need a fortuitous late gust at the end of the storm to do the cleaning.

Hopefully it will all fall in the northern hemisphere

The distant horizon is fading from view. Compare this sequence from sols 1225, 1233, and 1235, taken near the same local time:
http://marsrovers.jpl.nasa.gov/gallery/all...R9P2629L6M1.JPG
http://marsrovers.jpl.nasa.gov/gallery/all...W0P2688L6M1.JPG
http://marsrovers.jpl.nasa.gov/gallery/all...W0P2689L6M1.JPG

Still no word on tau for 1235, but tau was a bit higher on 1225 than 1233. Yet the horizon is hazier on 1233. This seems to suggest that the atmosphere was dustier at low altitudes on 1233, but a bit clearer overall. Is this due to dust settling? Or to new dust being kicked up from the surface?

Things aren't pretty right now, my sources tell me that tau is about 5 and increasing.
Let's all hope Oppy survives this...

So it is at Spirit's on sol 1255 as well...

More than 5! NIGHTMARE.



I'll have to change the scale of the Y axis on my graph!!!

It's much worse than that -- it also means I have to sit here hitting ^r on an innocent Dust Devil page when I should be looking after someone's network security...

I've been rather distracted since seeing your last Tau chart heading back upwards for the last few days.

Could anyone enlighten me as to the typical timescale (if there are such things with such a small sample set to work from) for a regional or hemispheral storm to develop into a global storm, if it decides to do so? Or even how long the Viking and 2001 global storms took to develop from this stage to their full extent?

fredk already quoted this from the last status update, but it bears repeating:



>8.

Ouch... What's the bare minimum of whrs Opportunity needs to survive and can it survive with less than that for a short period of time? 150 whrs? How about 100?

The storm encountered by Mariner 9 in 1971 began in late September and didn't fully subside until December. So it wouldn't be unreasonable to think in terms of two months. Though we have no way of knowing what portion of that storm had tau of 5 or greater. Still, it could be bad and it could be long.

Fuzy horizon, dark ground, too red skies,
I request for clearer days.

Damn, the winds must be really picking up.

This is bad...very, very bad. The worst part about it is the wait for information.

This is like having a family member in the hospital and not knowing whether they are going to make it.

http://www.unmannedspaceflight.com/index.php?showtopic=821

Funny then. Not funny in THIS situation IMHO.

These could be the last pictures Opportunity transmits:

http://qt.exploratorium.edu/mars/opportuni...W0P1569L0M1.JPG

I have a fair ammount of confidence that even with a couple of weeks of <200whrs essentially out of touch all together - the vehicle would be recoverable once the tau gets back to <3. It's summer, it's warmer at night, perhaps the MiniTES lens will go (but it hasn't with some very cold nights so far) - but I'm quietly confident.

Doug

Speaking of lenses, I wonder what all this particle movement is doing to the hazcams. It's not uncommon in the US desert Southwest regions for autmobile windshields to become buffed and pitted in sandstorms. The MI has a cover, and the pancam can be pointed downward but those hazcams just have to sit and take it.

Spirit's FHAZ's are filthy right now, that much is obvious.

Doug

Tau 5! very scary.

I remember Mariner 9....... was just out of High School and wandering the hippie havens of the University of Akron.

That 1971 dust storm actually helped dispel the notion that Mars was just a larger version of cratered Luna but with a wisp of atmosphere. I will never forget seeing the "spots" materialize out of the settling dust...
which turned out to be the summits of the Tharsis volcanoes..... the dust storm of 71 helped to highlight those features. And a revolution in our understanding of Mars.

Now, 36 years later, we are seeing the effects of one of these storms from the ground. I cannot help but find this fascinating as well as scary.

But....

Hang in there, Little Rovers....

Craig

From Lemmon's site, Oppy's at 5.0-5.2 (sol 1236), "estimate based on array energy due to a no-activity plan, and last data for a couple sols".

Hang in there, indeed.

Also from Lemmon's site


edit: used the above to produce power estimates for Oppy, not sure how accurate they are.

Click to view attachment

I'd be lying if I said I am not concerned, but I am not terribly worried at this point, either. Oppy has felt she had enough power to take some images through sol 1236, even though the images have decreased in number. Furthermore, she has transmitted tens of images, including those "dust lifting" movies taken on sols 1233-4 as recently as today (sol 1237), two sols into tau5 conditions.

They have apparently suspended imaging as of sol 1237 and are not planning activities for a while, I am guessing as a precautionary measure.

One thing that we all can feel happy about is that both rovers look to be as clean as whistles, and so are able to absorb as many photons as are able to penetrate the gloom. Being a die hard optimist, I was looking for other good news, and this is the best I could come up with. There has been a bit of a correlation between tau, as recently measured by Spirit, and that measured by Opportunity. Just look at Doug's graph. According to Dr. Lemmon's site Spirit has seen a slight decrease from it's recent peak tau, from 3.8 to 3.6. That was tosol. We might not, but then again we just might, see dust levels on this side of the planet do something similar. Let us pray that it doesn't get much worse.

Just as an example of how the current low power situation affects the rover activities, sol 1235 was initially planned to be a driving sol but only a few imaging sequences were executed, driving was cancelled. Imaging started around 10:54 local time and finished at 11:35; just 40 minutes of activities.

If we compare that with, let's say, sol 1203, the difference is significant. That sol imaging activities started at 09:41am, followed by a 60m drive lasting from 12:35 to 14:04, and finished at 16:31; that means a rover alive and kicking during almost seven hours!

Hang in there girls.



Imaging during sol 1236 have been apparently cancelled too.

yikes.

Yikes indeed

And I think it would look even worse with the figures for the previous month in, a nice flat line at first and then it would sky rocket.

It would not be a good idea to put a trend line on that curve as it would be too depressing.

Roy

Think positive, we have a clean rover and summer temperatures. Things could be much worse with dirty solar panels and during winter times.

I'm worried about the fact that the last 5.2 value is based on array energy only. Look at these images from Horton:

http://www.flickr.com/photos/hortonheardawho/831774782/

I get the impression there's more dust on the deck on sol 1235. What if the power is dropping because there's more and more dust deposition?

From this image, I tend rather torward more dust coming along with the wind than from above. Anyway we will need "back side" wind after the clouds of dust are over, I think.

Rather such dust stroms on Mars than one from Earth http://tagesschau.sf.tv/sfvideo/view/173120/1 (click "Breitband (450 kbit/s)")

Here is the development of the
Duststorm seen through the eye of Spirit.
Views taken with the L5 Pancam between
Sol 1216 and Sol 1255

jvandriel