Planet Four Talk

How many pictures have neither fans nor blotches?

  • KatherineR by KatherineR

    I am new to this project, and not seeing any fans or blotches in most of the pictures. Is that normal, or am I missing them?


  • p.titchin by p.titchin in response to KatherineR's comment.

    Hi Katherine, good to see you on the discussion boards. Firstly, some areas have more vents producing #fans and #blotches than others, some parts of areas don't produce venting at all. This is part of our job, to mark where they occur, and the changes from Mars year to year. Secondly, the activity varies
    with the season, so in the Mars winter, theiCO2 ice is not heated, so, no sublimation, no pressure build up, and no vents. As we watch in the Mars Spring, the activity increases. In the Summer the ice may be largely 'gone, the 'defrosted' surface looks more like desert, and- no CO2 to sublime, so no vents! Other areas are off the 'permanent ice cap (so called South polar layered deposits- SPLD's) and they have venting, but the temporary ice surface looks as if it is made up of polygonal plates, and and the vents seem to produce central "blotches. I hope this helps.Here are 3 image links, the first showing the more classic fans from the ice cap. This is in the Spring, so we have clean vented frost fans, (show as blue) overlayed by later dirty frost , with different directions showing wind shifts. APF0002gsr . and the second the blotches and plates from the seasonal ice APF0002hi7 , and thirdly the defrosted surface APF0002jrt . Enjoy! Welcome aboard. ~Pete