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Posted by: volcanopele Oct 2 2009, 01:43 AM

The latest PDS release for Cassini is now online at http://pds-imaging.jpl.nasa.gov/data/cassini/cassini_orbiter/

I've posted the RADAR swaths from T48 and T49 at http://pirlwww.lpl.arizona.edu/~perry/RADAR/ . These swaths include observations of the ISS playa, Tui Regio (yep, it does look a lot like Hotei Regio), Shikoku Facula, Belet, and the southern mid-latitudes.

One image I want to highlight is from one of the T48 swaths. It covers northern Shikoku Facula. You can see a river channel running from a playa in the center of northern Shikoku east out to the margin between the Shangri-la dune fields and Shikoku. Very cool stuff.
http://pirlwww.lpl.arizona.edu/~perry/RADAR/Northern_Shikoku_Facula.jpg

Posted by: Juramike Oct 2 2009, 02:32 AM

Very cool!

Thank you for hosting these!

Posted by: ngunn Oct 2 2009, 11:55 AM

Great stuff. What happens when the liquids meet the dunes is a crucial question with big implications - for relative timescales of active processes amongst many others. At first glance that dunefield looks to me like it's been attacked and partly erased by the liquid flow, perhaps in a sudden brief event??

In the T49 I noticed what could be a similar situation, though less well resolved. A stream seems to originate just above a possible crater remnant and flow off to the left, cutting through dunes at right angles.

Posted by: titanicrivers Oct 2 2009, 03:36 PM

"I've posted the RADAR swaths from T48 and T49 at http://pirlwww.lpl.arizona.edu/~perry/RADAR/ .


Much thanks VP for the posting! The T48 and T49 swaths (especially the latter) jump around a bit and I've included a context map of the swaths modified from Spilker's presentation http://saturn.jpl.nasa.gov/files/20090728_CHARM_5yr_Spilker.pdf as the swaths are not labeled on the Perry SAR swath site overview map.

Posted by: titanicrivers Oct 3 2009, 12:09 AM

Here's a rough guess at the location of the ISS Playa piece of the T49 swath. I've placed the darkest portion over the location where the new lakes (now playa) had appeared. (Perhaps VP has a more accurate placement to post!)

Posted by: titanicrivers Oct 3 2009, 07:48 PM

There was overlap to the T49 playa swath and the T36 southern latitudes swath. As these were over a year apart and the overlap (-75S and85W) area was relatively near the lakes that had formed between 2004 and 2005 (see PIA11147) http://photojournal.jpl.nasa.gov/catalog/PIA11147 and were in the process of drying up I thought it might be worthwhile to look for changes. Looking at the overlap area it seems some variation relates to SAR viewing direction and swath resolution but also there may be changes related to playa drying up between T36 (10/2/07) and T49 (12/2/08). What do ya think!? (I know I'm probably all 'wet' on this one)

Posted by: Olvegg Oct 3 2009, 09:34 PM

Thank you for this comparison, titanicrivers!
These calderas seems to be dry in both cases It's been too long since a rainy season...

Here's the enhanced view of playa itself. Very eroded terrain with calderas:

Posted by: titanicrivers Oct 4 2009, 04:25 PM

Absolutely! Seeing changes over several years would also help answer a crucial 'timescale' question whether channels erase dunes or dunes cover channels. Looking at Shikoku over the time period 2006-2009 (click on graphic) seems to show no definitive changes in that regard. (main changes relate to SAR look angle and resolution).

Posted by: volcanopele Oct 7 2009, 09:57 AM

I have added to the RADAR SAR page maps for the north and south poles (RADAR only). These are complete through T49:

http://pirlwww.lpl.arizona.edu/~perry/RADAR/NPoleMap_128ppd_grid.jpg

http://pirlwww.lpl.arizona.edu/~perry/RADAR/SPoleMap_128ppd_grid.jpg

Posted by: ngunn Oct 7 2009, 12:18 PM

Those are brilliant! - at least the bits I could see before my computer blanked out half way through opening them. Could you please post versions at, say, 64 resolution?

EDIT: tried it at home and got the whole thing fine.

Posted by: titanicrivers Oct 8 2009, 06:52 AM

Here's a combination of the S pole swaths VP has posted with the ISS map of the same. I've added some grid markers and swath labels. A very cool area appears at top where the T39 river and the T7 shoreline appear. As VP has mentioned in the changing lakes thread when the south pole wet season returns the Mezzoramia Basin that these 2 swaths relate to may be the big lake on Titan!

Posted by: titanicrivers Oct 10 2009, 06:16 AM

And next are the North polar SAR swaths VP has just posted. These are placed on an ISS N polar map grid. Lots of awesome lake and river topography!

Posted by: titanicrivers Oct 11 2009, 04:30 AM

From the T28 north polar swath an extensive river system is seen near 255W and 75N (see below). One SARTopo strip runs along the river and is shown in place on the map. The river runs approximately 375 km and from its upper tributaries to its lowest reaches there is a drop of around 500 m. This gives an overall gradient of 500 m/375km or 1.33 m per km or around 5 feet per mile, not much different from many terrestrial streams!

Posted by: nprev Oct 11 2009, 04:38 AM

That's almost literally fantastic! How odd to contemplate this...