Rev205 and T102, Southern sub-Saturn temperate lake? Options

[titanicrivers]

Rev205 (May 31 – Jul 2 ’14) has begun. http://www.ciclops.org/view/7892/Rev205 There is a Titan flyby (T102) and Cassini’s approach appears quite similar to T101. ISS will again image the southern sub-Saturn hemisphere. This will examine the interesting southern temperate zone where VIMS and ISS had imaged several temperate lakes just to the east of T102’s field of view. http://www.lpi.usra.edu/meetings/lpsc2012/pdf/2766.pdf Looking at that great ISS map one is drawn to a small dark region near 330 W and 45 S. This little place has had good VIMS http://photojournal.jpl.nasa.gov/catalog/PIA09034 and SAR (T50) coverage and I wonder if it is considered a temperate lake candidate?

[titanicrivers]

This area of T50 appears not to have been characterized as a geomorphic unit and sits between Hummocky and Plains terrains. SarTopo suggest its relatively low in elevation and there may be a draining channel or two nearby. Perhaps someone has denoised and destriped the PDS version of this area; that may help decide its morphology. (? JohnVV)!

[JohnVV]

i did not see this until today

tonight i can grab the pds image and process it

then post different levels of denoising

imported the file "BIBQI28S319_D181_T050S01_V02.IMG"
into ISIS and exported a raw normalized to 1,65535
rotated 270 Deg.
and cropped the area
1) original image
2) denoised with detail
3) denoised with less detail



a G+ album
https://plus.google.com/u/0/photos/10269590...168099862280065
to remove the horizontal seams will require some more work

[JohnVV]

my apologizes with the move from my 100% public Picasa albums to the G+ royally "bleeped"-up G+ albums
new folders are NOT being automatically made public
the above G+ link is NOW public

[titanicrivers]

Not a problem John VV; thanks for the link and images. Not sure what this structure is. ? mainly a patch of dark dunes or perhaps a shallow lake or playa bottom.? Perhaps VP might comment.

[JohnVV]

the radar data is reflectance the light areas are rough and the dark is smooth
( the same type as the venus data )
so i would expect that dark area to be a lake .Like a small lake in a marsh here on earth .


a crop of the PDE noise reduced area
if i remove TOO much noise it becomes a bit blurry

unlike the venus data this is very VERY noisy .So if i work it too much the data starts to become "artificial"( inpainted) or "flat" depending on the way i denoise

[Tom Tamlyn]

I have a question about references in this thread to the "temperate zones" of Titan.

Has Titan, like the Earth, been separated Phil Stooke and his colleagues into major zones separated by great circles of latitude, with the northern temperate zone bounded to the North by Titan's Arctic Circle at 66.5° north latitude and to the south by the northerly tropic circle (I don't suppose it's called the tropic of cancer) at 23.5° north latitude?

Or is the term "temperate zone" a more ad hoc one, referring to warmer spots where the contents of Titan's lakes are not frozen?

My Google due-diligence on the question mostly returned articles about mythology and video games . . .

Cheers,

TTT

Edited to correct a misspelling.

This post has been edited by Tom Tamlyn: Jun 13 2014, 06:49 AM

[Juramike]

Titan does seem to be latitudinally stratified. Equatorial dunes, mid-lat stuff, empty lakes, and filled lakes, in the Northern hemisphere. Sorta-kinda similar but a little bit drier in the South.

The term for the Titan's mid-latitudes is officially the "Titan's mid-latitudes", and unofficially "the Blandlands".
"Desolate plains" has also been used.

There is no solid (!) evidence that Titan's lakes are frozen. Titan is just a tad too warm, even at the poles. There is a very small difference between the equatorial temperatures (95 K) and the polar temperatures (91 K). But even that is just enough to mess (!) with the expected equilibrium ratio of nitrogen/methane/ethane/propane in the lake fluids.

If the lakes are in equilibrium with the atmosphere (which may not be the case), polar lake fluids would have a different equilibrium concentration than temperate lakes.

One estimate of these values is in Cordier et al., 2009. (freely available here, check out table 3 in the text: http://iopscience.iop.org/1538-4357/707/2/..._707_2_L128.pdf.

Local humidity can also be a driver and affect evaporation rates thus composition. At equilibrium, humidity (actual vapor pressure vs. saturation vapor pressure) is 100%. If the equatorial areas are drier, they could affect evaporation rates and the mix of lake composition.

Methane is most volatile (nitrogen dissolves into methane, so it gets affected, too.)
Ethane is not volatile (but could evaporate on a long enough time-scale. We are talking multi-year climate timescale.)
Propane is seriously not volatile (Myr timescale????)
1-Butene is not predicted to be produced by atmospheric chemistry models to any appreciable extent. But if a puddle of that material were present, it would not evaporate, even on geological timescales.

[JohnVV]

the area in question is at -45 Lat and 330 ( -30 ) Long
a map projected ( simple cylindrical ) image with some of the stripping removed
North is UP


G+ "photo" image
https://plus.google.com/u/0/photos/10269590...901291398562941

[titanicrivers]

Two nice discussions about the T102 (and previous T101) flybys are now found on the Cassini mission homepage. http://saturn.jpl.nasa.gov/news/cassinifea...eature20140617/
http://saturn.jpl.nasa.gov/mission/flybys/titan20140618/

[Ian R]

A shot of Kraken Mare from just the other day:

[Ian R]

This is a fairly rough-and-ready (some might say grotty, even) 4-frame NAC mosaic, encompassing the entirety of the northern wetlands:

[titanicrivers]

Some more T102 flyby images
RGB composite

Four of the approach images from about 250K km CB3 filter.