Al-Amal orbiter tracks unusual northern summer dust storm on Mars
Click for full figure.
Scientists, using UAE’s Al-Amal Mars orbiter, have documented the occurrence of a rare high northern latitude summer dust storm whose origin appears linked to both a major canyon in the northern ice cap as well as the giant sand dune seas that surround that ice cap.
The EMM [instrument on Al-Amal] observed a distinct dust cloud on 10 September 2021. That was outside of the classical Martian dust storm season. The observed dust cloud is an arc-shaped dust storm, typically observed at the northern polar cap edge. This type of non-season dust storm is a well-known phenomenon, but this particular case is interesting because the dust cloud has frontal structure. A large atmospheric front is unusual in this location and season.
EMM’s unique observational coverage adds value to this observation, by providing a sequence of four camera images of the frontal dust cloud, separated by 2–3 hr. The frontal dust cloud shows very little movement over 7–8 hr, that is, it is quasi-stationary. We estimated the wind speed and direction by tracking internal motion of the dust cloud. In one case, the estimated wind is consistent with near-surface easterly winds at the polar cap edge.
The two images to the right are adapted from the paper’s figure 3. The yellow line in the top image indicates the location of the dust storm’s front (about 1,200 miles long), aligned with the canyon Chasma Boreale, marked by the black line, that cuts a 300-mile-long and 4,600-foot-deep gash into the North Pole ice cap.
The storm’s wind speeds were estimated very roughly to be about 16 feet per second, about 10 mph. In Mars’ thin atmosphere these winds would be so gentle that they would be almost imperceptible.
The storm front’s alignment with Chasma Boreale is intriguing, but the overview map below suggests another intriguing alignment.
The yellow-black line on the map corresponds roughly to the yellow-black line in the top image above. Note how the storm seems to sit above the giant Olympia Undae sand dune sea that surrounds the north pole ice cap. In fact, this storm seems to suggest that the dust that formed that sea might have actually come from the dust that is mixed into the cap’s water ice layers, several thousand feet thick but exposed on the walls of Chasma Boreale.
Many avalanches have been spotted on the cliff edges of the north pole ice cap, each producing small and very temporary dust clouds. The temperature differences between the top of Chasma Boreale and its floor produce winds. Both events combined could drive the dust out of the canyon and onto the sand dune sea. Thus, the sand dune sea is created, with this rare dust storm illustrating this process.
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Your help allows me to do this kind of intelligent analysis. I take no advertising or sponsors, so my reporting isn't influenced by donations by established space or drug companies. Instead, I rely entirely on donations and subscriptions from my readers, which gives me the freedom to write what I think, unencumbered by outside influences.
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Click for full figure.
Scientists, using UAE’s Al-Amal Mars orbiter, have documented the occurrence of a rare high northern latitude summer dust storm whose origin appears linked to both a major canyon in the northern ice cap as well as the giant sand dune seas that surround that ice cap.
The EMM [instrument on Al-Amal] observed a distinct dust cloud on 10 September 2021. That was outside of the classical Martian dust storm season. The observed dust cloud is an arc-shaped dust storm, typically observed at the northern polar cap edge. This type of non-season dust storm is a well-known phenomenon, but this particular case is interesting because the dust cloud has frontal structure. A large atmospheric front is unusual in this location and season.
EMM’s unique observational coverage adds value to this observation, by providing a sequence of four camera images of the frontal dust cloud, separated by 2–3 hr. The frontal dust cloud shows very little movement over 7–8 hr, that is, it is quasi-stationary. We estimated the wind speed and direction by tracking internal motion of the dust cloud. In one case, the estimated wind is consistent with near-surface easterly winds at the polar cap edge.
The two images to the right are adapted from the paper’s figure 3. The yellow line in the top image indicates the location of the dust storm’s front (about 1,200 miles long), aligned with the canyon Chasma Boreale, marked by the black line, that cuts a 300-mile-long and 4,600-foot-deep gash into the North Pole ice cap.
The storm’s wind speeds were estimated very roughly to be about 16 feet per second, about 10 mph. In Mars’ thin atmosphere these winds would be so gentle that they would be almost imperceptible.
The storm front’s alignment with Chasma Boreale is intriguing, but the overview map below suggests another intriguing alignment.
The yellow-black line on the map corresponds roughly to the yellow-black line in the top image above. Note how the storm seems to sit above the giant Olympia Undae sand dune sea that surrounds the north pole ice cap. In fact, this storm seems to suggest that the dust that formed that sea might have actually come from the dust that is mixed into the cap’s water ice layers, several thousand feet thick but exposed on the walls of Chasma Boreale.
Many avalanches have been spotted on the cliff edges of the north pole ice cap, each producing small and very temporary dust clouds. The temperature differences between the top of Chasma Boreale and its floor produce winds. Both events combined could drive the dust out of the canyon and onto the sand dune sea. Thus, the sand dune sea is created, with this rare dust storm illustrating this process.
Readers!
My annual February birthday fund-raising drive for Behind the Black is now over. Thank you to everyone who donated or subscribed. While not a record-setter, the donations were more than sufficient and slightly above average.
As I have said many times before, I can’t express what it means to me to get such support, especially as no one is required to pay anything to read my work. Thank you all again!
For those readers who like my work here at Behind the Black and haven't contributed so far, please consider donating or subscribing. My analysis of space, politics, and culture, taken from the perspective of an historian, is almost always on the money and ahead of the game. For example, in 2020 I correctly predicted that the COVID panic was unnecessary, that the virus was apparently simply a variation of the flu, that masks were not simply pointless but if worn incorrectly were a health threat, that the lockdowns were a disaster and did nothing to stop the spread of COVID. Every one of those 2020 conclusions has turned out right.
Your help allows me to do this kind of intelligent analysis. I take no advertising or sponsors, so my reporting isn't influenced by donations by established space or drug companies. Instead, I rely entirely on donations and subscriptions from my readers, which gives me the freedom to write what I think, unencumbered by outside influences.
You can support me either by giving a one-time contribution or a regular subscription. There are four ways of doing so:
1. Zelle: This is the only internet method that charges no fees. All you have to do is use the Zelle link at your internet bank and give my name and email address (zimmerman at nasw dot org). What you donate is what I get.
2. Patreon: Go to my website there and pick one of five monthly subscription amounts, or by making a one-time donation.
3. A Paypal Donation or subscription:
4. Donate by check, payable to Robert Zimmerman and mailed to
Behind The Black
c/o Robert Zimmerman
P.O.Box 1262
Cortaro, AZ 85652
You can also support me by buying one of my books, as noted in the boxes interspersed throughout the webpage or shown in the menu above.
UAE seems to really be getting their money’s worth out of this spacecraft. Chapeau!