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.
THEMIS Image Data Page for I11896042.
CENTER_LATITUDE = 49.5458
CENTER_LONGITUDE = 349.094
MINIMUM_BRIGHTNESS_TEMPERATURE = 145.350
MAXIMUM_BRIGHTNESS_TEMPERATURE = 296.671
http://themis-data.asu.edu/img/I11896042
THEMIS Image Data Page for I05548016.
CENTER_LATITUDE = 34.5145
CENTER_LONGITUDE = 202.03
MINIMUM_BRIGHTNESS_TEMPERATURE = 304.961
MAXIMUM_BRIGHTNESS_TEMPERATURE = 314.052
http://themis-data.asu.edu/img/I05548016
THEMIS Image Data Page for I03396032.
CENTER_LATITUDE = 45.524
CENTER_LONGITUDE = 164.151
MINIMUM_BRIGHTNESS_TEMPERATURE = 302.723
MAXIMUM_BRIGHTNESS_TEMPERATURE = 311.785
http://themis-data.asu.edu/img/I03396032
THEMIS Image Data Page for I02967002.
CENTER_LATITUDE = 76.7838
CENTER_LONGITUDE = 128.354
MINIMUM_BRIGHTNESS_TEMPERATURE = 267.048
MAXIMUM_BRIGHTNESS_TEMPERATURE = 314.033
http://themis-data.asu.edu/img/I02967002
THEMIS Image Data Page for I029674002.
CENTER_LATITUDE = 78.274
CENTER_LONGITUDE = 288.536
MINIMUM_BRIGHTNESS_TEMPERATURE = 258.639
MAXIMUM_BRIGHTNESS_TEMPERATURE = 296.812
http://themis-data.asu.edu/img/I02974002
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
THEMIS Image Data Page for I01913037.
CENTER_LATITUDE = 49.7447
CENTER_LONGITUDE = 272.881
MINIMUM_BRIGHTNESS_TEMPERATURE = 265.707
MAXIMUM_BRIGHTNESS_TEMPERATURE = 312.959
http://themis-data.asu.edu/img/I01913037
The maximal temperatures in these cases are significantly higher than the maximal temperatures expected at the given latitudes, especially for the temperatures above 300K, which would be expected only near the equator, at least in the Northern hemisphere.
How accurate are these THEMIS brightness temperatures?
You can do your own search for high temperatures by going to the page:
THEMIS Public Data Releases.
http://themis-data.asu.edu/
and clicking on the Advanced tab. Then you can enter the latitudes, longitudes and temperature ranges you want to search for.
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.
It would also help to find out if these high temperatures are maintained in subsequent IR imaging.
It is interesting that 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
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".
Some visible light images of the region:
MOC narrow-angle image E01-01908.
http://barsoom.msss.com/moc_gallery/e01_e0...1/E0101908.html
THEMIS Image Data Page for V02834004.
http://themis-data.asu.edu/img/V02834004.html
Bob Clark