“On December 5, ISS will image a half-phase Titan at a distance of 2.5 million kilometers (1.55 million miles). The camera will image the sub-Saturn hemisphere of the satellite, allowing researchers to continue to study the recent weather changes that have been occurring across Titan's equatorial region and that have brought methane rain to select regions of previously dry terrain”.
Seems a shame the NAC or WAC couldn’t take a few images before Dec 5th say on the second. Based on the SSS it would seem the area in S Senkyo (around 310 W and -20 ) that almost certainly had intense precipitation is better seen on the 2nd below left, and may be beyond the terminator and invisible on the 5th below on right. Also I couldn't confirm with the SSS that Titan would be as close as 2.5 Mkm on the 5th ???
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Grr, no I goofed. I had Enceladus still selected in Celestia and didn't notice that when I wrote down the distance. Let me get a corrected number.

Yep, that should be 3.42 million kilometers.

The distance has been corrected in the Looking Ahead article. Thanks for the catch, titanicrivers.

oops i need to move the post
http://www.unmannedspaceflight.com/index.p...mp;#entry167421

Here's the most likely area to scrutinize for changes related to the T72 storm (image below enhanced from ISS map). Enlargement of the dark circular areas or new roundish dark areas or widened dark channels might be seen on the Dec 5th images.
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Some Dec 5th images are in the raws but I really couldn't spot any obvious clouds nor surface features changes that suggest localized flooding. Anyone else see changes? I'll have to work more with the images as initially there seem to be an enhanced channel on one of the CL1 CB3 images.

Here's a possible surface change in the S Senkyo region (between -10 and -20 latitude and 320W and 330W) present on the Dec 20 CL1CB3 filtered images. The dark area (arrow) seems fairly prominent now compared to pre- T72 storm images of the same area. Haven't gone through all previous images and the lighting and processing of the images differs but the change is similar to S Polar ISS images following the 2004 storm.
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A closer view of the possible surface change is compared to the pre-storm ISS basemap. The projected T-72 storm cloud appears to have been directly over the region of change suggesting this may be a shallow collection of methane rain (perhaps now just a playa).
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Wow. You've made quite a convincing case there.
I would really love to hear what the professionals think about this. Have they noticed it?

I can neither confirm or deny anything you have experienced with these images. Next question please.

Agree lots more image analysis is needed before one can say if any significant changes are present in above and below images.
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at a quick glance it dose not appear that there is a change , other than rotation .

a nice bit there .

Here is another pair to ponder. The raw images are a closer match as far as distance to Titan and longitudinal center of the image. Arrow points to possible albedo difference. Images rotated so N is up and slightly enhanced.
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Now that's much more compelling evidence. Nice work.

I appreciate your comment ugordan! Hopefully the observation will hold up under closer scrutiny.

I took the two observations you mentioned - the 2009 one is available at the PDS - and made a flicker gif. CB3 stacked images divided by a MT1 frame in both cases. 50% original resolution, though not much detail is lost due to atmospheric scattering.

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I don't know how many of the other subtle albedo changes are due to haze differences (whether in MT1 or closer to the ground in CB3 frames), but the Senkyo change is indeed compelling.

Ok that's exciting! WOW!

From the Rev 143 Looking Ahead article: http://www.ciclops.org/view/6681/Rev143


I'll take that as confirmation that this surface change is considered real.

Hard to know! The word 'additional' also appears in the Rev 142 Looking Ahead article and this is before the Dec 20th images that clearly showed the S Senkyo change. Its possible those smaller Dec 5 images did show something although not in the same place as the 310-330 longitude region was beyond the terminator in the unlit portion of Titan.

Another attempt to more precisely locate the September 27, 2010, T72 'arrow storm' cloud tops
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It is interesting to compare the apparent T72 storm Senkyo changes to those noted in the S Polar region of Titan following the large 2004 polar storms (see http://photojournal.jpl.nasa.gov/catalog/PIA11147 ) The image below compares the two regions to the same scale. The new S polar lakes that appeared are indicated in the white oval. The most obvious Senkyo change (darker triangular area) is from a much lower resolution image and its composition is still uncertain at this point.
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While talking about the S Polar storm and subsequent appearance of lakes in above post I was curious what the Cassini flyby (Ta) saw in the raw images from Oct 2004. One of the best (taken Oct 25, 2004) is shown below (left image panel A) and compared with those of Schaller et al had taken two days before (Oct 23 panel 'B') with Keck adaptive optics. This polar storm was massive (see the Oct 8 Keck image) and was rapidly dissipating when Cassini flew by. Placing a celestia grid to locate the storm residual cloud puts it over the precise area where the lakes were noted in 2005 (see polar projection figure right) suggesting the October 2004 storm was the source of the new lakes.
The interesting Schaller, Brown, Roe and Bouchez paper can be found here.
http://www.gps.caltech.edu/~mbrown/papers/ps/largecloud.pdf
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I do believe we *cough* strongly suggested that in our 2009 paper.

Stayed tuned to this channel in the near-future as certainly this story isn't over...

HA! I was gonna preface my last post with 'due apologies to VP for the rehash'! I haven't read your full paper....can you give me the link. Thanks!

edit: I believe this is the paper!
http://ciclops.org/media/sp/2009/5480_12560_0.pdf

Nice work!

Thanks for the link actually. It used to be that we had so few papers that I could keep these things straight, what info is in what paper. Let's just say that this is no longer the case... We hint at the connection between the flooding of Arrakis Planitia and the October 2004 storm in the 2009 paper, but we will be making a bigger point of it soon.

New (taken Jan 21, 2011) Titan images cover the area of possible change in S Senkyo. The photo is taken from 3.437M km however and so have much less resolution than the Dec 20th 2010 or Mar 21, 2009 images that suggest a change in surface albedo (see posts #’s 13 and 16 above). The darker region near 325W and – 20 S is not very visible at least in my enhanced image. Next months (Rev 145 T74) Titan flyby hopefully will include high resolutions of the Senkyo area* as storm changes may be vanishing if liquids do not remain on the surface for very long.
*Edit: Approx WAC camera view of Senyko on Feb 18 at 22hr just past closest approach on right; courtesy the SSS.
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Here is an image that puts a constraint on the appearance of the apparent albedo change in the S Senyko region. The raw image was taken on September 13th 2010 (just 2 weeks before the T72 storm images). Although relatively low in resolution the region of possible change appears a fairly uniform bright albedo (arrow) suggesting any changes occurred after that date.
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Just for fun: N00165573 animated overlay on the ISS basemap of S. Senkyo.
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Latest Cassini (CL1 CB3) views of Senkyo show less dark albedo change than in December. Hopefully closer views later this month should show more detail and possibly residual surface changes.
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As VP has mentioned he and colleagues will be saying more about their observations on the surface effects of the T72 storm (in up coming LPSC 2011 meeting). The abstracts for the meeting are available on the meeting website http://www.lpi.usra.edu/meetings/lpsc2011/?view=abstracts including Turtle, Perry et al report on T72 arrow storm effect in the Belet area of Titan. http://www.lpi.usra.edu/meetings/lpsc2011/pdf/1459.pdf

The stuff about Arrakis Planitia and the October 2004 storm is in a paper now in press over in the journal Icarus:

Shoreline Retreat at Titan’s Ontario Lacus and Arrakis Planitia from Cassini Imaging Science Subsystem Observations
E.P. Turtle, J.E. Perry, A.G. Hayes and A.S. McEwen
http://dx.doi.org/10.1016/j.icarus.2011.02.005

Cassini raw images of Titan from March 5 show the Belet area well. This area showed amazing changes relating to the T72 arrow storm. (see A and B below, images from the Turtle, Perry et al abstract: http://www.lpi.usra.edu/meetings/lpsc2011/pdf/1459.pdf
An enhanced, cropped image from March 5, 2011 (N00168995) is shown in C below. Image C suggests the albedo darkening changes seen in B have reverted considerably back to their appearance before the deluge from the 'arrow' storm.
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It appears the Belet changes were beginning to revert a bit in the Jan 15 2011 images as well. Below is a composite of CL1 CB3 views from about 995K km.
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Titanicriver kinda let the cat out of the bag a week early, but that's okay. I'm stunned it took THAT long. Anyways...

Cassini Sees Seasonal Rains Transform Titan's Surface
http://www.ciclops.org/view/6744/

Image Releases are at:
http://www.ciclops.org/view_event/155/Meth..._Titans_Deserts

That's the press release for our paper now published in Science regarding the late September/October arrow storm and equatorial cloud breakout and subsequent surface change. We saw a substantial area along the southern boundary of Belet darken as a result of these storms in October, as well as smaller areas near the southern boundary of Senkyo (first spotted in December) and in southwestern Adiri. More recently, as the "waters" have receded (or simply dried up), patches of brighter material have been spotted. We are still trying to figure out the best explanation for this, but one likely one is that the rains have cleaned off "gunk" off portions of Titan's surface, revealing brighter material beneath the...ummm....gunk (not a scientific term I know, but it is easier to say than unidentified hydrocarbon surficial material).

For those who have access to Science you can find our paper at: http://www.sciencemag.org/content/331/6023/1414 . If you don't have access, send me a pm with your email addy and I will send a copy along to you. I just need to download the reprint myself first

In addition to publicizing findings from these last few exciting months, we are also announcing findings from our cloud monitoring campaign during the extended mission that ended, coincidentally enough with the observation of the arrow storm. These observations included what we call "caboose" observations, cloud tracking periods added on in the 2-3 days before or after a Titan flyby. These allowed us to capture movies of clouds going around the north pole of Titan as well as a set of streaks at the moon's southern mid-latitudes back in December 2009. These movies are now posted on the CICLOPS website. The original paper was published in GRL here: http://www.agu.org/pubs/crossref/2011/2010GL046266.shtml Unfortunately, I don't have institutional access to GRL, so if anyone does, and can send it to me, then I can email it to anyone who requests that one.

Note: I now the GRL paper (actually I had it all along, but I thought it was a draft version...). So if you want that one too, let me know.

I had the JSC Earth Observation Lab dig out and scan that last image, which I found
initially in a Bulletin of the American Meteorological Soc. paper.... Gemini 4 was the first
US manned mission over 1 day - as well as Ed White's famous spacewalk, there was also an
Earth imaging experiment, using the 70mm Hasselblad camera with an 80mm lens, which
caught the first good spaceborne image of sand dunes (if I am not wrong) as well as various
cloud and landscape images including this one.

An analysis in the literature shortly after the flight showed the dark streak saw about 2 inches
of rainfall, whereas the undarkened area had less than 0.25 inch.

I'd be interested if people know of examples of this effect since (seems like these dark streaks
should be observed a lot...?)

Ralph, do you mean examples from orbital imagery alone? I suspect that this phenomenon is so subtle at local scales that it is not obvious from any other perspective.

Do you want wet, or inundated? Inundated, I'd look for satellite imagery of Lençóis Maranhenses National Park. High local water table under dune fields, seasonal rains.

Or Indian monsoons:
http://earthobservatory.nasa.gov/IOTD/view.php?id=3856

Nprev - I mean orbital (well, not strictly - I'd accept images from interplanetary space! Or even sounding rocket)
Stevesliva - I mean damp/wet, NOT inundated. Plenty of remote sensing of flooding. I mean darkened by
being damp, as one often sees at the small scale on sidewalks or on the beach or on playas.

Because the Titan darkening occurs not only in depressions, it does not seem to be inundation...

Swath seems to be a good keyword, but there's not so much in the way of rain swaths. Snow swaths, hail swaths, tornado swaths, etc are much more common.

http://www.spc.noaa.gov/coolimg/coolrain/index.html
http://cimss.ssec.wisc.edu/goes/blog/wp-co...H010207_RGB.JPG
from
http://cimss.ssec.wisc.edu/goes/blog/archi.../2007/06/page/2
http://cimss.ssec.wisc.edu/goes/blog/categ...y-rain-flooding (mentions swaths of wet ground not visible in visible wavelengths)

Dig it, Ralph; merely a clarifying question. I suspect that many examples may be found, particularly in the GOES image set.

Well, yes. But I'd prefer not to have to search myself - I wondered if annotated examples exist from
GOES/Meteosat much like Steve's last example (but at shorter wavelengths)
If it doesnt exist, maybe some prof out there can set up a hunt as a student project....

Here's a link to an animated GIF that shows the flooding and evaporation of Lake Poopo, Bolivia over the course of a year. This uses GOES-E images.
http://www.flickr.com/photos/31678681@N07/5541410235/

Painting a broad view of the Arrow Storm changes including those in Belet (as just beautifully published in Science) and those in S Senkyo (brighter areas noted in the Science supplement, darker areas not). The arrow storm was presumably made up of numerous individual cells and might be better thought of as an equivalent of an intense low pressure system on earth.
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Cool, thanks, Mike. A lot going on there.

And 'Lake Poopo' - someone *HAS* to propose that to the IAU for a Titan feature......

To quote VP in post #34 above ... 'but one likely one is that the rains have cleaned off "gunk" off portions of Titan's surface, revealing brighter material beneath the...ummm....gunk' ...

The S Senkyo area may be a good example of what VP is suggesting. A S Senkyo topography map (color swaths from Zebker and Stiles et al http://www.sciencemag.org/content/324/5929/921.full), while far from complete did interestingly enough include a swath near the area of bright and dark change as seen in the Dec 20th ISS image. There's a slight bump in part of the bright outer rim suggesting its higher and making a case for a whitening of a topographic high washing darker 'gunk' downslope into a relatively lower basin. The figure below shows the basemap and then Dec 20 image and finally the SAR altimetry swaths. The arrow points at the possible higher terrain. The whole area was directly under the Arrow Storm.
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Titan imaged on June 11th displays Senkyo and Belet regions in this most recent distant view after the storm. Perhaps a hint of brightenings along the path of the Sept 2010 arrow storm remain. Kraken appears in the hazy north. Imaged rotated 60 degrees clockwise and enhanced.
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The post storm Senkyo images of Dec 20 2010 are now available in the PDS archive. The PDS versions are used for the close-up views comparing the pre 3/21/2009 and post 12/20/2010 ISS images from just under 1M km. Additional darkened areas seem visible (small yellow arrows). The larger area noted last year (larger yellow arrow) is quite evident. The dark areas may represent places of methane rain accumulation. The ISS basemap shows the area in high resolution pre-storm; small dark albedo areas (yellow circle) exist which appear to localize with some of the darks spots post storm.
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