Al-Amal orbiter tracks unusual northern summer dust storm on Mars

Fig. 3 from Al-Amal paper
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.
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Martian auroras as seen by UAE’s Al-Amal orbiter

Aurora types on Mars
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Using data gathered by the Al-Amal orbiter (“Hope” in English), scientists have identified three types of aurora on Mars. The image to the right, figure 1 from their paper, shows these types, crustal field aurora, patchy aurora, and sinuous aurora. From the abstract:

We categorize discrete auroral patterns into three types: those near strong vertical crustal magnetic field, patchy aurora near very weak crustal fields, and a new type we call “sinuous,” an elongated serpentine structure that stretches thousands of kilometers into the nightside from near midnight in the northern hemisphere.

All three types generally occur during the Martian night, and evolve quickly over periods of less than 45 minutes. The first type, which is generally the brightest, forms over terrain where Mars’ residual magnetic field is strongest and vertically oriented, and was most often seen over the southern cratered highlands centered between the large impact basins Argyre and Hellas. The third type, sinuous aurora, was more unusual:

These we are calling “sinuous discrete aurora,” due to their thin, elongated, and sometimes serpentine shapes. They share several key traits: (a) they appear in the northern hemisphere away from strong crustal fields, (b) they usually connect to the dayside in the far north but also sometimes separately at lower latitudes, (c) they extend for thousands of kilometers into the night side, (d) they appear on both dusk and dawn sides, and (e) their shapes change moderately and brightnesses shift by factors of up to two over timescales of ∼20 min (i.e., the time between swaths, as shown in the differences between Figures 1j and 1k [in the figure above).

The existence of aurora on Mars has been known since the 2000s. These observations however are the first that show more details beyond a fuzzy patch.

Dust and clouds in the Martian atmosphere, as seen by UAE’s Al-Amal orbiter

Two new science papers have just been released detailing results from the Al-Amal (Hope) Mars orbiter that was designed and built by American universities for the United Arab Emirates (UAE).

Both papers used data obtained from the orbiter’s infrared spectrometer, dubbed the Emirates Mars Infrared Spectrometer (EMIRS).

Daily cloud cover changes on Mars
Figure 1 from paper. Click for full image.

First, the instrument tracked the daily changes in the planet’s cloud cover.

A prominent region of clouds that is commonly observed near the equator during Mars’ cold season—known as the aphelion cloud belt—was observed to reach a minimum near midday, with more clouds typically observed in both the morning and afternoon. Distinct differences were found in clouds observed near volcanoes, which tended to reach a minimum before local noon and increase throughout the afternoon.

The figure to the right shows this. In the morning and afternoon (LTST’s 7 and 17), there is a high concentration of clouds in the equatorial region above the Tharsis Bulge where the highest Martian volcanoes are located. During the middle of the day (LTSTs 11 and 13) this cloud cover largely dissipates, with a corresponding increase in cloud cover in Hellas Basin, in the southern hemisphere.

The second paper took a more general look at the data, including the change in temperature depending on elevation as well as dust and water content during the Martian northern spring and summer. From the abstract:
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Global image of Mars from UAE’s Al-Amal orbiter

Mars as seen by Al-Amal in January 2022
Click for original image.

Cool image time! The United Arab Emirates (UAE) today released several new images taken by its Al-Amal Mars orbiter, showing the changing atmospheric conditions on Mars between September ’21 and January ’22.

The photo to the right, cropped and annotated by me, is the January image, showing the dust storm conditions that presently exist in the equatorial regions of Mars. The lighter puffy cloud-like features in the center of the image are a 1,500 mile wide dust storm centered on the equator. The white dot indicates the approximate spot where Perseverance sits in Jezero Crater, within that storm.

The previous Al-Amal image from September (available at the link) shows the whole Martian hemisphere with generally clear skies.

Below is a recent photo taken by Perseverance illustrating these dusty conditions.
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Atomic oxygen in Mars’ atmosphere, as seen by Al-Amal

Oxygen distribution on Mars

The UAE’s Al-Amal Mars orbiter on July 19, 2021 released a new spectroscopic image, showing the global distribution of atomic oxygen in the Martian upper atmosphere.

The Emirates Ultraviolet Spectrometer (EMUS) mapped the distribution of atomic oxygen in the planet’s upper atmosphere, showing a dense patch emerging from the nightside into the new day.

The photo to the right, cropped and reduced to post here, shows this.

Over the next two years, covering one single Martian year, Al-Amal will monitor the distribution of this oxygen to see how it fluctuations from season to season, as well as from day to day. Gather this information will help the theorists untangle the past atmospheric history of Mars.