Martian high north latitude hot spots?

[exoscientist]

Some THEMIS IR images show surprisingly high temperatures at high northern latitudes on Mars. The data for the examples below are taken from the data labels for the images. You'll need to download and open in a program such as NASAView or programs specifically written for THEMIS the Brightness Temperature Image files of file type .IMG on each of the linked pages to read this data. <br /><br />THEMIS Image Data Page for I11896042. <br />CENTER_LATITUDE = 49.5458 <br />CENTER_LONGITUDE = 349.094 <br />MINIMUM_BRIGHTNESS_TEMPERATURE = 145.350 <br />MAXIMUM_BRIGHTNESS_TEMPERATURE = 296.671 <br />http://themis-data.asu.edu/img/I11896042 <br /><br /><br />THEMIS Image Data Page for I05548016. <br />CENTER_LATITUDE = 34.5145 <br />CENTER_LONGITUDE = 202.03 <br />MINIMUM_BRIGHTNESS_TEMPERATURE = 304.961 <br />MAXIMUM_BRIGHTNESS_TEMPERATURE = 314.052 <br />http://themis-data.asu.edu/img/I05548016 <br /><br /><br />THEMIS Image Data Page for I03396032. <br />CENTER_LATITUDE = 45.524 <br />CENTER_LONGITUDE = 164.151 <br />MINIMUM_BRIGHTNESS_TEMPERATURE = 302.723 <br />MAXIMUM_BRIGHTNESS_TEMPERATURE = 311.785 <br />http://themis-data.asu.edu/img/I03396032 <br /><br /><br />THEMIS Image Data Page for I02967002. <br />CENTER_LATITUDE = 76.7838 <br />CENTER_LONGITUDE = 128.354 <br />MINIMUM_BRIGHTNESS_TEMPERATURE = 267.048 <br />MAXIMUM_BRIGHTNESS_TEMPERATURE = 314.033 <br />http://themis-data.asu.edu/img/I02967002 <br /><br /><br />THEMIS Image Data Page for I029674002. <br />CENTER_LATITUDE = 78.274 <br />CENTER_LONGITUDE = 288.536 <br />MINIMUM_BRIGHTNESS_TEMPERATURE = 258.639 <br />MAXIMUM_BRIGHTNESS_TEMPERATURE = 296.812 <br />http://themis-data.asu.edu/img/I02974002 <br /><b></b> <div class="Discussion_UserSignature"> </div>

 

[exoscientist]

Some of these images contain noise so it needs to be determined how valid these measurements are. What might help is to locate where these maximal temperatures are occurring within the image and try to relate them to geomorphology in visible light images. <br />It would also help to find out if these high temperatures are maintained in subsequent IR imaging. <br /><br />It is interesting that one of the images lies within Cydonia:<br /><br />THEMIS Image Data Page for I02834003. <br />CENTER_LATITUDE = 40.1813 <br />CENTER_LONGITUDE = 349.993 <br />MINIMUM_BRIGHTNESS_TEMPERATURE = 306.029 <br />MAXIMUM_BRIGHTNESS_TEMPERATURE = 322.379 <br />http://themis-data.asu.edu/img/I02834003<br /><br />and contains a feature that has been claimed to appear as a "smoking pyramid". It's 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". <br />Some visible light images of the region:<br /><br />MOC narrow-angle image E01-01908. <br />http://barsoom.msss.com/moc_gallery/e01_e06/images/E01/E0101908.html<br /><br />THEMIS Image Data Page for V02834004. <br />http://themis-data.asu.edu/img/V02834004.html<br /><br /><br /> Bob Clark <br /> <div class="Discussion_UserSignature"> </div>

 

[exoscientist]

Another interesting case is:<br /><br />THEMIS Image Data Page for I02026005.<br />CENTER_LATITUDE = 39.1376<br />CENTER_LONGITUDE = 251.959<br />MINIMUM_BRIGHTNESS_TEMPERATURE = 302.213<br />MAXIMUM_BRIGHTNESS_TEMPERATURE = 322.192<br />http://themis-data.asu.edu/img/I02026005<br /><br /> 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.<br /> Here's a visible light image:<br /><br />THEMIS Image Data Page for V02026006.<br />http://themis-data.asu.edu/img/V02026006<br /><br /> Again it would be interesting to find out if the highest temperature in the IR image is reached where there is geomorphological evidence of venting in the visible light images, such as pseudocraters for example.<br /><br /><br /> Bob Clark<br /><br /><br /><br /> <div class="Discussion_UserSignature"> </div>

 

[exoscientist]

Nick Hoffman described how to read the THEMIS brightness images here:<br /><br />How to do it with NASAVIEW. <br />Posted by Nick Hoffman on 8/7/2005 6:02:09 AM <br />In Reply to: re: Martian high north latitude hot spots? posted by Robert Clark on 8/6/2005 5:06:41 AM <br />http://habitablezone.com/space/messages/390308.html<br /><br /><br />He discussed this image:<br /><br />THEMIS Image Data Page for I02026005. <br />CENTER_LATITUDE = 39.1376 <br />CENTER_LONGITUDE = 251.959 <br />MINIMUM_BRIGHTNESS_TEMPERATURE = 302.213 <br />MAXIMUM_BRIGHTNESS_TEMPERATURE = 322.192 <br />http://themis-data.asu.edu/img/I02026005 <br /><br />He observed the hottest areas were in the Sun-facing walls in the image, which argues against the maximum temperature being due to a hot spot. <br />But a key fact about this image is that even the minimum temperature is quite hot for this latitude. Do a search for instance on http://themis-data.asu.edu . Click the Advanced button, then search on the IR images in the latitude range 37 to 41. You'll get a couple of thousand images. The highest maximal temperatures you'll see will be overwhelmingly in the 250's. There are only perhaps 2 or 3 in the 300's. So this particular image even has it's minimal temperature 40 to 50 degrees hotter than most other maximum temperatures at that latitude. <br />In reading some articles about the brightness temperatures it turns out they are affected by albedo as well as surface temperature. So you might guess this is an unusually bright area. But the corresponding visual image does not give that impression:<br /><br />THEMIS Image Data Page for V02026006. <br />http://themis-data.asu.edu/img/V02026006<br /><br />It would be interesting to find out if current or pas <div class="Discussion_UserSignature"> </div>

 

[exoscientist]

The THEMIS image is actually in the caldera of Alba Patera, which you would expect for a geothermal hot spot. <br />This MGS image near the same area shows two dark streaks at the bottom: <br /><br />MOC narrow-angle image R16-00268 <br />North middle-latitude crater in Alba Patera caldera. <br />http://www.msss.com/moc_gallery/r16_r21/images/R16/R1600268.html <br /><br />They both have the feature of widening from a central origin point. I consider this characteristic of material being vented and then being spread aerially by wind. If they arose simply from a dust deposit, you would expect the streaks to only extend straight out from the deposit with the width staying the same as the width of the deposit. Alba Patera is known to have had recent lava flows. Dark streaks whatever their cause would have to be geologically recent. Due to dust cover we would actually expect dark streaks to only have a lifetime measured in millenia or less. <br />There are many other dark streaks in the accompanying context image which also have the feature of widening from a central point. The famous "slope dark streaks" near the equator also have this feature, but those are due clearly to gravity-induced flow down a slope. The dark streaks in the Alba Patera region have the appearance of wind carried flow, as well as being far from the equator. However, the slopes directions do need to be checked by MOLA measurements to be sure of this. <br />But particular evidence these streaks are wind-developed as well as to the possibility of venting is provided by the upper of the two steaks in image R1600268. This streak appears not to originate from a nearby crater, but slightly above the crater in the image. But by enlarging the image you see this streak actually does originate from the crater. What happens is the streak is directed upwards in the image, then horizontally to the right. This could be due to a ve <div class="Discussion_UserSignature"> </div>