Arsia Mons Anomaly?, Recent Mars Express Imagery shows odd feature Options

[Hungry4info]

Is that a Plume on Arsia Mons?
https://scilogs.spektrum.de/go-for-launch/i...-on-arsia-mons/

Images of the Tharsis region show the emergence of a new prolonged feature that appears to cast a long shadow. It is not visible in this attached image from 06 August 2018.


Then we can see something newish near Arsia Mons (the vertical streak) in this image from 19 Sep 2018.


And then most striking is this image from 23 Sep 2018, where it appears that a significant shadow is cast (in the direction of the streak in the last image, admittedly).


I'm not familiar enough with Martian meteorology to know if this is just a normal occurrence, but it does look weird, at least to me. Hopefully someone will have ideas. If the answer to this is obvious then feel free to lock and/or delete the thread.

[nprev]

I think that it was an excellent 'teachable moment'. It's easy to forget that Mars' atmosphere, though exceedingly thin by terrestrial standards, is still capable of producing surprisingly substantial water and CO2 clouds more frequently than might otherwise be assumed.

[JRehling]

It's easy to forget that Mars' atmosphere, though exceedingly thin by terrestrial standards, is still capable of producing surprisingly substantial water and CO2 clouds more frequently than might otherwise be assumed.

Taking my own pictures of Mars, I'm much more conscious of that than I was when I "merely" perused spacecraft imagery, which is often up-close and often avoids the clouds.

It's not an overstatement to say that there are often/usually clouds in the following contexts: the sunrise limb, the sunset limb, the winter polar regions, above the five tallest volcanoes after sunrise or before sunset. I'd say that it's rare to see a picture of Mars without clouds in at least one of those locations. Here's a picture of mine taken in June 2016 with a 6" telescope that shows Arsia, Ascraeus, and Pavonis as clouds on the right limb. It's easier to see them this way than when they're cloudless. Olympus Mons, experiencing early afternoon, is visible cloudless to their upper left.

Attached thumbnail(s)