Imagine it's night; you're aboard an airplane, looking downward. All you see is complete darkness.
Now, put on your IR glasses. Imagine you see this:
link
What do you think you are looking at?!?
You are flying over a volcanic region, so I think is quite normal to suppose we are looking at hot spots.

Now, move your cursor over -5.224 N, 243.17 E.
See that white stripe?
Now, switch to daytime IR view (from listbox above): you see that? The black area?

What is it?
What is cold during day and warm during night?!?

Any idea if HiIRISE images exists for this region?


Here around, exactly at -5.636 N, -118.751 E , there's also the "strange anomaly" known as "mars hole" in thse days; this is an hi-res picture. I can't find similar resolution pictures for "my" anomaly. Any help?

__________________
-- Jumpjack --

You've got multiple issues here.

The daytime observation has things like shadows etc. The angles involved will produce light and dark areas in a daytime Vis or IR image that will not be there during a Night time IR image.

Secondly - relative to the surroundings - rocks will be 'cold' during the day and 'warm' at night. Things like craters, or rocky gullies, both stand out a lot in Night IR as very bright because they retain the heat they absorbed during the day.

And during the day, because they take longer to warm up relative to things with low thermal inertia such as sand and dust, they appear IR dark.

You've not really found an anomaly of any sort - Mars is covered in rocky features that will do the same.

As for a HiRISE image - you would have to be very very very very lucky. A full HiRISE image is about 5 x 10-15km. In global terms its like a postage stamp on a football field. http://hirise.lpl.arizona.edu/anazitisi.php is the place to search for - I couldn't find one in the area you're asking about.

Ditto THEMIS - http://themis.asu.edu/mars-bin/webmap.pl - nothing in that specific area in the Vis. http://themis-data.asu.edu/img/V05847002.html is nearby and has many similar features to the area you're talking about.



Doug

Could liquid water have such a thermal behaviour?
The HIRISE image you can find between -6,-5N and 240, 242 E ("Candidate Cavern Entrance Northeast of Arsia Mons "), perhaps could be "just" a small water lake. Or not?
There's plenty of ice in Mars underground; that one is a volcanic (=maybe hot) region; couldn't some ice be melted down and create a lake? Water would evaporate, but it would be "replaced" by other melting ice, so keeping the lake alive.

Are you able to find day and night IR images at higher res for the "candidate cavern"? I'm trying with no success.

__________________
-- Jumpjack --

I found another search engine for HiRISE images:
http://pds-imaging.jpl.nasa.gov/search/index.jsp

I get 29 results for same coordinates, but I can display only one: how can I display an IMG image, or convert it to any other format??

__________________
-- Jumpjack --

This is a very interesting image:
link

How do they know elevations of this area in such a detail? Couldn't same method be applied to "mars holes", to determine if they're actually holes?

__________________
-- Jumpjack --

The elevation map of Victoria crater was generated using multiple observations from HiRISE imaging off-track by several degrees to generate ultra-long baseline stereo.

You couldn't do the same with the caves as a black hole has no features to co-register between mutiple stereo observations.

If there were areas taht were volcanically hot - we'd know. THEMIS would have gone off the scale with the sort of heat involved with a volcano.

Long lived large expanses of open water are not possible - it would be a boiling, steaming mess. A collapsed lava-tube is the simplest explanation for the multiple cave entrances that have been observed.

Doug

it's really a pity; I really hoped to see such a flyby over the "holes"!
quicktime movie
(higher res here)

__________________
-- Jumpjack --

Thanks for the link.
I also found some Mars "hot spots" but these in the area of the mid-latitude Northern plains.

One of the images lies within Cydonia:

THEMIS Image Data Page for I02834003.
CENTER_LATITUDE = 40.1813
CENTER_LONGITUDE = 349.993
MINIMUM_BRIGHTNESS_TEMPERATURE = 306.029
MAXIMUM_BRIGHTNESS_TEMPERATURE = 322.379
http://themis-data.asu.edu/img/I02834003

It contains a feature that has been claimed to appear as a "smoking
pyramid". This is an area in visible light imaging that has light colored
areas giving the appearance of gas or water vapor release. It would be
interesting to find out if the maximal temperature in the IR image
corresponds to this "smoking pyramid".
Some visible light images of the region:

MOC narrow-angle image E01-01908.
http://barsoom.msss.com/moc_gallery/.../E0101908.html

THEMIS Image Data Page for V02834004.
http://themis-data.asu.edu/img/V02834004.html


Another "hot spot":

THEMIS Image Data Page for I02026005.
CENTER_LATITUDE = 39.1376
CENTER_LONGITUDE = 251.959
MINIMUM_BRIGHTNESS_TEMPERATURE = 302.213
MAXIMUM_BRIGHTNESS_TEMPERATURE = 322.192
http://themis-data.asu.edu/img/I02026005

This happens to lie in Alba Patera, the volcanic region. This image is
much more free of noise making it more likely the measurement is an
accurate one.
Here's a visible light image:

THEMIS Image Data Page for V02026006.
http://themis-data.asu.edu/img/V02026006


The link you gave is good in that you can get an IR image of a specific region by giving the latitude and longitude. However, what I need is a way to find the sites in an IR image where the given max temperatures occur so I can try to make a comparison to geomorphogical features, such vents, fissures, etc.
Anyone know how to do this?


Bob Clark

Sorry, but I can't see any "hot spot" in images you linked: can you specify pixel position in images?

Anyway,I'm quite sure first image portraits an ancient martian archipelago!

Yes, a comparison scale would be nice, so we could know if "white" means "20°C" or "200°C".

__________________
-- Jumpjack --

Probably you can find something useful here:
http://www.mars-ice.org/software.php

http://isis.astrogeology.usgs.gov/Is...forum.php?f=45

__________________
-- Jumpjack --

I can't specify where it is locally. I can only state the information accompanying the image, that the max temperature is at 322 K, 49 C. This is quite high at this northern latitude.
What I'm trying to do is find a program, software that can locate where it is occurring in the image.
An archipelago is an interesting idea. It would suggest an ancient ocean on Mars.




Bob Clark