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Titan's changing lakes
ngunn
post Jan 29 2009, 07:22 PM
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Today's big news?
http://ciclops.org/view/5471/CASSINI_FINDS...ILL_TITAN_LAKES

Changes in the south polar region were announced late last year. Is there more to this story now??

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ngunn
post Jan 29 2009, 07:45 PM
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That's brilliant, thanks VP.
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Jason W Barnes
post Jan 29 2009, 09:11 PM
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I actually much prefer that these press releases coincide with actual scientific papers; it increases the signal-to-noise. Any damned idiot can put out a press release, but without a peer-reviewed paper to back it up it's just gum-flapping. This is the first time that this discovery has been announced. You here of the cognescenti know of it from Dr. Turtle's DPS talk, but this is the first public release.

The ISS team did this one right, and by the book, so don't give them crap for it!

- VIMS Jason
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ngunn
post Jan 30 2009, 02:14 AM
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QUOTE (Jason W Barnes @ Jan 29 2009, 09:11 PM) *
The ISS team did this one right, and by the book, so don't give them crap for it!


No-one's doing that - certainly not me. I'm 100 percent delighted with what they (and all the other instrument teams) do. The images and map associated with that release are new to me. If they were posted here before, I missed them. Until now I didn't know exactly where the newly 'flooded playa' was, and I found the comments in the article most interesting.

Not so long ago there were people here (not the mission scientists) saying that Titan doesn't receive enough solar energy to empty and fill the lakes on a seasonal basis. I'm hoping 2009 brings us more, and that this is just the beginning of Cassini's record of Titan's surface changing with the seasons.

While you're on the line - can you shed any more light on the question of using the ISS polarisers to look for sky reflections in the lakes? There probably are reasons why it isn't worth trying but I can't discover them.
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Jason W Barnes
post Jan 30 2009, 05:33 PM
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QUOTE (ngunn @ Jan 29 2009, 08:14 PM) *
While you're on the line - can you shed any more light on the question of using the ISS polarisers to look for sky reflections in the lakes? There probably are reasons why it isn't worth trying but I can't discover them.


Well, since the lakes are at the poles the incidence angle is always going to be 70 degrees or higher. Therefore to see a specular reflection, you'll need to look with emission angle of 70 degrees or higher as well. As you know from processing the ISS data, the empirical atmospheric correction that they do does not produce reliable surface photometry this close to the limb. Look at Mezzoramia in the Turtle et al. paper -- the brightness looks quite different between these two flybys, when there's every reason to think that it hasn't actually changed at all.

Another reason is that you'd need a very specialized encounter geometry in order to be in position to see the specular reflection. I can't speak for ISS. But as for VIMS, we've made the decision that if we were in such a geometry, we'd rather be looking straight down at the ground with 0 emission angle, as that would mean new territory at fine resolution.

This type of observation may have been rendered moot by the T49 RADAR altimetry pass -- we'll have to wait until that's been released to find out. Hope this helps,

- VIMS Jason
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ngunn
post Jan 30 2009, 08:16 PM
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That is indeed most helpful. Although I'm still not clear why the direction of the sun should be a constraint if one is only looking for a reflection of the hazy sky, I can well appreciate how the other difficulties might mount up.

What is the RADAR turning up I wonder? Like many others I await that too with eager anticipation.

Patience is needed there I know, but the upcoming flyby will provide plenty of excitement in near-ish real time. Seatbelts fastened, a quick wave at the lake and in we go!
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Posts in this topic
- ngunn   Titan's changing lakes   Jan 29 2009, 07:22 PM
- - ngunn   Aah, there's this: http://saturn.jpl.nasa.gov/...   Jan 29 2009, 07:32 PM
- - volcanopele   Here are some the associated graphics: http://pho...   Jan 29 2009, 07:34 PM
- - volcanopele   QUOTE (ngunn @ Jan 29 2009, 12:22 PM) Cha...   Jan 29 2009, 07:35 PM
- - ngunn   That's brilliant, thanks VP.   Jan 29 2009, 07:45 PM
|- - Jason W Barnes   I actually much prefer that these press releases c...   Jan 29 2009, 09:11 PM
|- - ngunn   QUOTE (Jason W Barnes @ Jan 29 2009, 09:1...   Jan 30 2009, 02:14 AM
|- - Jason W Barnes   QUOTE (ngunn @ Jan 29 2009, 08:14 PM) Whi...   Jan 30 2009, 05:33 PM
|- - ngunn   That is indeed most helpful. Although I'm stil...   Jan 30 2009, 08:16 PM
|- - rlorenz   QUOTE (ngunn @ Jan 30 2009, 03:16 PM) Wha...   Feb 4 2009, 03:36 PM
- - Decepticon   Does anyone have a radar swath overlay-ed of the s...   Feb 2 2009, 10:57 AM
|- - titanicrivers   QUOTE (Decepticon @ Feb 2 2009, 04:57 AM)...   Feb 2 2009, 03:15 PM
- - ngunn   Excellent!!   Feb 4 2009, 09:11 PM
- - nprev   Oh, goodygoodygoody...Santa Ralph hints that a bit...   Feb 5 2009, 12:37 AM
- - Juramike   Bam! There it is! Lorenz et al. LPSC (2...   Feb 7 2009, 04:48 PM
- - ngunn   Brilliant discovery - brilliant paper title! ...   Feb 7 2009, 07:20 PM
|- - rlorenz   QUOTE (ngunn @ Feb 7 2009, 02:20 PM) Bril...   Feb 9 2009, 06:22 PM
|- - Jason W Barnes   QUOTE (rlorenz @ Feb 9 2009, 12:22 PM) Bu...   Feb 10 2009, 01:52 AM
- - ngunn   Taking this together with earlier VIMS results, ma...   Feb 8 2009, 08:37 AM
- - nprev   Hmm. Sorry to hear that, Ralph; it was indeed a gr...   Feb 9 2009, 07:57 PM
- - ngunn   Or perhaps other 'disadvantaged' topics we...   Feb 9 2009, 09:15 PM
|- - rlorenz   QUOTE (ngunn @ Feb 9 2009, 04:15 PM) Perh...   Feb 15 2009, 04:21 AM
- - ngunn   Great - another potentially variable lake property...   Feb 15 2009, 07:51 PM
|- - Jason W Barnes   VIMS Ontario Lacus paper is now out in print from ...   Apr 10 2009, 11:32 PM
- - ngunn   A huge thank you (again) for making another fascin...   Apr 11 2009, 07:26 AM
- - titanicrivers   As above. A very readable and yet compelling pape...   Apr 11 2009, 12:28 PM
- - ngunn   Is anybody going to have a go at matching the alti...   Apr 11 2009, 10:04 PM
|- - Jason W Barnes   QUOTE (ngunn @ Apr 11 2009, 03:04 PM) Is ...   Apr 12 2009, 06:25 PM
- - HughFromAlice   The variation in the height of the surface of Onta...   Aug 23 2009, 06:08 AM
|- - Gsnorgathon   Hey! I got lucky and got the whole article. (D...   Aug 23 2009, 05:29 PM
|- - rlorenz   QUOTE (HughFromAlice @ Aug 23 2009, 01:08...   Aug 23 2009, 06:26 PM
|- - djellison   QUOTE (rlorenz @ Aug 23 2009, 07:26 PM) F...   Aug 24 2009, 08:01 AM
- - nprev   It's a fascinating result, Ralph, and clearly ...   Aug 23 2009, 09:08 PM
- - AndyG   Reading this made me think of the artwork by Richa...   Aug 24 2009, 08:26 AM
- - ngunn   BIG changes observed at Ontario Lacus in the 4th a...   Sep 1 2009, 11:24 AM
|- - titanicrivers   QUOTE (ngunn @ Sep 1 2009, 05:24 AM) BIG ...   Sep 1 2009, 12:40 PM
|- - Hungry4info   QUOTE (titanicrivers @ Sep 1 2009, 06:40 ...   Sep 1 2009, 01:15 PM
- - ngunn   Strange, it works for me OK, although it does invo...   Sep 1 2009, 01:34 PM
|- - titanicrivers   QUOTE (ngunn @ Sep 1 2009, 07:34 AM) Stra...   Sep 1 2009, 05:20 PM
|- - HughFromAlice   QUOTE (titanicrivers @ Sep 2 2009, 02:50 ...   Sep 1 2009, 11:30 PM
- - belleraphon1   All.. I found I had to outside the forum and go ...   Sep 1 2009, 01:54 PM
- - belleraphon1   And, of course, I copy the wrong abstract... sorry...   Sep 1 2009, 01:57 PM
- - remcook   How well do the ISS and RADAR 'shorelines...   Sep 1 2009, 02:36 PM
- - ngunn   I have to admit I'm baffled by the numbers rig...   Sep 1 2009, 03:09 PM
- - Sunspot   So when will us common folk get to see the T57/T58...   Sep 1 2009, 03:40 PM
- - ngunn   I've edited my previous post 42 to correct a n...   Sep 1 2009, 06:18 PM
- - volcanopele   Well, hopefully they will broadcast the oral sessi...   Sep 1 2009, 11:34 PM
- - ngunn   This presentation will compare apparent shorelines...   Sep 3 2009, 11:12 AM
- - Olvegg   NASA Cassini Radar Observes Seasonal Change in Tit...   Oct 7 2009, 06:11 PM
|- - titanicrivers   QUOTE (Olvegg @ Oct 7 2009, 01:11 PM) NAS...   Oct 8 2009, 03:32 AM
- - ngunn   Spectacular changes - and so plain to see! (No...   Oct 7 2009, 08:38 PM
- - ngunn   I am trying to post the VIMS image of the bottom r...   Oct 7 2009, 09:50 PM
- - volcanopele   I think the ISS/VIMS/RADAR story is coming along n...   Oct 7 2009, 10:02 PM
|- - Webscientist   QUOTE (volcanopele @ Oct 8 2009, 12:02 AM...   Oct 8 2009, 08:54 PM
- - ngunn   Link from remcook: http://www.sciencedirect.com/s...   Oct 7 2009, 10:28 PM
- - volcanopele   I guess my comment is that I think they have it ba...   Oct 7 2009, 11:58 PM
- - Sunspot   How wide is thay channel where it appears to open ...   Oct 8 2009, 07:53 AM
- - volcanopele   The landing site might depend on the season when t...   Oct 8 2009, 09:03 PM
- - nprev   Hmm. It does seem as if the 'desert' equat...   Oct 8 2009, 09:13 PM
|- - ngunn   QUOTE (nprev @ Oct 8 2009, 10:13 PM) Huyg...   Oct 8 2009, 09:53 PM
- - volcanopele   Yeah, and storms are not unheard of at the latitud...   Oct 8 2009, 09:18 PM
- - nprev   Gotcha. I'm definitely thinking flash floods a...   Oct 8 2009, 09:36 PM
- - djellison   Some posts have been removed from this thread, as ...   Oct 9 2009, 04:33 PM
- - titanicrivers   Check out Photojournal http://photojournal.jpl.nas...   Oct 10 2009, 03:01 PM
- - ngunn   VIMS sees specular reflection from Kraken Mare: Q...   Oct 25 2009, 09:48 PM
|- - Jason W Barnes   QUOTE (ngunn @ Oct 25 2009, 02:48 PM) On ...   Oct 26 2009, 02:00 PM
- - ngunn   And there's so much more - here: (struggling ...   Oct 25 2009, 10:50 PM
- - ngunn   Personal anecdote: perhaps not many people remembe...   Oct 26 2009, 12:01 AM
|- - Jason W Barnes   QUOTE (ngunn @ Oct 25 2009, 05:01 PM) The...   Oct 26 2009, 05:32 PM
|- - rlorenz   QUOTE (Jason W Barnes @ Oct 26 2009, 01:3...   Nov 1 2009, 03:11 PM
|- - Jason W Barnes   QUOTE (rlorenz @ Nov 1 2009, 08:11 AM) As...   Nov 2 2009, 06:54 PM
|- - rlorenz   QUOTE (Jason W Barnes @ Nov 2 2009, 01:54...   Nov 6 2009, 08:58 PM
|- - volcanopele   QUOTE (rlorenz @ Nov 6 2009, 01:58 PM) Wo...   Nov 6 2009, 09:26 PM
|- - Jason W Barnes   QUOTE (rlorenz @ Nov 6 2009, 01:58 PM) Hm...   Nov 7 2009, 05:54 AM
- - ngunn   Another morsel from the conference abstracts. Any...   Oct 26 2009, 01:34 PM
- - ngunn   Catching the lakeshine: Radar 21st December ...   Oct 26 2009, 02:33 PM
|- - Jason W Barnes   QUOTE (ngunn @ Oct 26 2009, 07:33 AM) Cat...   Oct 26 2009, 02:46 PM
- - ngunn   Yeah, you caught the sun's direct reflection a...   Oct 26 2009, 03:04 PM
- - ngunn   Thanks, Jason. Congrats to the team and good luck ...   Oct 27 2009, 12:41 PM
- - ngunn   Excuse a very basic question: would that be one pi...   Nov 1 2009, 07:25 PM
|- - Juramike   QUOTE (ngunn @ Nov 1 2009, 02:25 PM) Excu...   Nov 1 2009, 08:05 PM
||- - ngunn   QUOTE (Juramike @ Nov 1 2009, 08:05 PM) a...   Nov 1 2009, 09:17 PM
|- - Jason W Barnes   QUOTE (ngunn @ Nov 1 2009, 12:25 PM) Excu...   Nov 2 2009, 06:56 PM
- - ngunn   Article on seasonal and longer term change: http:/...   Nov 30 2009, 10:53 AM
|- - volcanopele   We shall see. I still think its seasonal.   Nov 30 2009, 05:17 PM
|- - Jason W Barnes   QUOTE (volcanopele @ Nov 30 2009, 10:17 A...   Nov 30 2009, 05:37 PM
- - volcanopele   Where are the south polar dry lakes? What do you ...   Nov 30 2009, 05:53 PM
|- - Jason W Barnes   QUOTE (volcanopele @ Nov 30 2009, 10:53 A...   Nov 30 2009, 07:05 PM
|- - ngunn   QUOTE (Jason W Barnes @ Nov 30 2009, 07:0...   Nov 30 2009, 09:06 PM
||- - Juramike   QUOTE (ngunn @ Nov 30 2009, 04:06 PM) Of ...   Nov 30 2009, 09:54 PM
|- - rlorenz   QUOTE (Jason W Barnes @ Nov 30 2009, 02:0...   Dec 1 2009, 11:23 PM
|- - Jason W Barnes   QUOTE (rlorenz @ Dec 1 2009, 04:23 PM) Ti...   Dec 2 2009, 05:54 PM
- - ngunn   I don't have access to the full paper, but fro...   Nov 30 2009, 06:00 PM
- - Juramike   I really, really, like the idea of the longer term...   Nov 30 2009, 07:51 PM
- - ngunn   I've been checking authors' websites, but ...   Nov 30 2009, 08:32 PM
- - volcanopele   Very nice article! Thanks for the link. Thou...   Nov 30 2009, 08:50 PM
|- - Juramike   QUOTE (volcanopele @ Nov 30 2009, 03:50 P...   Nov 30 2009, 09:46 PM
- - ngunn   Yes. And if the lakes 'breathe' into and o...   Nov 30 2009, 10:27 PM
- - remcook   So, what is new in this paper? The speculation abo...   Dec 2 2009, 08:35 AM
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