Ozone Production Over the Southern Winter Pole on Mars

Three separate ozone layers, each with their own characteristics, have been detected in the Martian atmosphere, by Mars Express. By comparing spacecraft data with computer models, scientists have found an explanation for how the layer that appears over the southern winter pole occurs.

It seems that the observed polar ozone layers are the result of the same atmospheric circulation pattern that creates a distinct oxygen emission identified in the Martian polar night. This circulation takes the form of a huge Hadley cell in which warmer air rises and travels poleward before cooling and sinking at higher latitudes. (Earth's atmosphere has two Hadley cells between the equator and the subtropics.)

Oxygen atoms produced by the ultraviolet photolysis (splitting) of CO2 (shown in blue [carbon] and red [oxygen] in this image) in the upper branch of the Hadley cell eventually recombine in the polar night to form molecular oxygen (O2) and ozone (O3). The concentration of ozone gas at night is dependent upon the supply of oxygen and the rate of destruction due to hydrogen radicals.

Hydrogen radicals can only be created by photolysis of water vapor above 25 km. During the northern summer, which takes place when Mars is near aphelion and consequently is further from the Sun than during southern summer, the conditions are such that water vapor is confined below 15 km, with the result that very few radicals are produced there and transported south, where they would destroy the ozone in the atmosphere. In contrast, during the southern summer the upper atmosphere is warmer and the altitude at which the atmosphere becomes saturated with water is above 40 km. The production of hydrogen radicals is increased and more of them flow to the northern winter poles resulting in a rate of ozone destruction about 100 times greater than above the southern pole.

No evidence for a comparable layer of ozone has been found above the northern pole of Mars. This dichotomy is confirmed by the Global Climate Model (developed at the Laboratoire de Météorologie Dynamique (LMD) and LATMOS, France), which predicts no high-altitude ozone layer in the northern polar night region.

For further details, read about A Seasonal Ozone Layer Over the Martian South Pole.

Illustration credit: ESA/ATG medialab

Unnamed Channel in Tyrrhena Terra

This small unnamed channel is located in southern Tyrrhena Terra.

Orbit Number: 51680 Latitude: -28.5234 Longitude: 80.2749 Instrument: VIS Captured: 2013-08-08 06:18

Photo credit: NASA/JPL-Caltech/Arizona State University

Koshoba Crater

From the USGS Astrogeology Science Center:

The IAU Working Group for Planetary System Nomenclature has approved the name Koshoba for a crater on Mars. For more information, see the map of MC-13 in the Gazetteer of Planetary Nomenclature.

Rabe Crater Dunes

This VIS image shows part of the dune field located on the floor of Rabe Crater. Compare this image with the IR image from earlier this week.

Orbit Number: 51669 Latitude: -43.6701 Longitude: 34.893 Instrument: VIS Captured: 2013-08-07 08:39

Photo credit: NASA/JPL-Caltech/Arizona State University

White Rock In Pollack Crater

This IR image shows the feature called "White Rock." In vis images, the feature is brighter in color that the surroundings. In this IR image the feature is dark, indicating that it is cooler than the surroundings.

Orbit Number: 51707 Latitude: -9.99112 Longitude: 24.6573 Instrument: IR Captured: 2013-08-10 11:29

Image credit: NASA/JPL-Caltech/Arizona State University

Rabe Crater Dunes in Infrared

This IR image shows part of the dune field on the floor of Rabe Crater. The dunes are "brighter" than the surrounding material, indicating that they are warmer. In visible wavelength images the dunes are dark, because they are comprised of basaltic sand.

Orbit Number: 51694 Latitude: -41.6772 Longitude: 34.5902 Instrument: IR Captured: 2013-08-09 10:00

Image credit: NASA/JPL-Caltech/Arizona State University

Daedalia Planum

Today's VIS image shows part of the extensive lava flows that comprise Daedalia Planum.

Orbit Number: 51637 Latitude: -20.9792 Longitude: 240.989 Instrument: VIS Captured: 2013-08-04 17:20

Photo credit: NASA/JPL-Caltech/Arizona State University

Small Ridge at Darwin Outcrop

This mosaic of four images taken by the Mars Hand Lens Imager (MAHLI) camera on NASA's Mars rover Curiosity shows detailed texture in a ridge that stands higher than surrounding rock. The rock is at a location called "Darwin," inside Gale Crater. Exposed outcrop at this location, visible in images from the High Resolution Imaging Science Experment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter, prompted Curiosity's science team to select it as the mission's first waypoint for several days during the mission's long trek from the "Glenelg" area to Mount Sharp.

MAHLI took the component images shortly before sunset on the 400th Martian day, or sol, of Curiosity's work on Mars (September 21, 2013). The camera was positioned about 10 inches (25 centimeters) from the rock. Scale is indicated by the Lincoln penny from the MAHLI calibration target, shown beside the mosaic.

The ridge resulted from a crack or vein in the surrounding rock becoming filled with material that was subsequently more resistant to erosion than the material of the surrounding rock. Researchers are investigating the textures and composition of ridges and the surrounding rock, which is a pebbly sandstone conglomerate. Reddish dust coats the surfaces seen in this image. The underlying rocks are gray, varying from nearly white to nearly black. The host rock in which the crack or vein formed is obscured in this image by the coating of dust and a thin layer of the rock's own debris -- loose pebbles and sand.

Researchers also examined ridges at Waypoint 1 with Curiosity's Alpha Particle X-ray Spectrometer (APXS), Chemistry and Camera (ChemCam) instrument and Mast Camera (Mastcam).

Image credit: NASA/JPL-Caltech/MSSS

Note: For more information, see PIA17362: Pebbly Sandstone Conglomerate Rock at Curiosity's 'Waypoint 1', PIA17363: Curiosity Uses X-ray Instrument's Data for Proximity Placement and NASA Rover Inspects Pebbly Rocks at Martian Waypoint.

Tunable Laser Spectrometer Mockup for Curiosity

This picture shows a lab demonstration of the measurement chamber inside the Tunable Laser Spectrometer, an instrument that is part of the Sample Analysis at Mars investigation on NASA's Curiosity rover. This demonstration uses visible lasers -- rather than the infrared ones on the actual spectrometer -- to show how the lasers bounce between the mirrors in the measurement chamber.

The TLS shoots laser beams into a type of measurement chamber that can be filled with Mars air. By measuring the absorption of light at specific wavelengths, the tool can measure concentrations of methane, carbon dioxide and water vapor in the Martian atmosphere and different isotopes of those gases.

Researchers are using Curiosity's 10 instruments to investigate whether areas in Gale Crater ever offered environmental conditions favorable for microbial life.

Photo credit: NASA/JPL-Caltech

Note: For more information, see NASA Curiosity Rover Detects No Methane on Mars.

Sand Dunes and Transverse Ridges in Noctis Labyrinthus

This colorful scene is situated in the Noctis Labyrinthus, perched high on the Tharsis rise in the upper reaches of the Valles Marineris canyon system.

Targeting the bright rimmed bedrock knobs, the image also captures the interaction of two distinct types of windblown sediments. Surrounding the bedrock knobs is a network of pale reddish ridges with a complex interlinked morphology. These pale ridges resemble the simpler “transverse aeolian ridges” (called TARs) that are common in the equatorial regions of Mars.

The TARs are still poorly understood, and are variously ascribed to dunes produced by reversing winds, coarse grained ripples, or indurated dust deposits. HiRISE observations of TARs have so far shown that these bedforms are stable over time, suggesting either that they form slowly over much longer time scales than the duration of MRO's mission, or that they formed in the past during periods of very different atmospheric conditions than the present.

Dark sand dunes comprise the second type of windblown sediment visible in this image. The dark sand dune seen just below the center of the cutout displays features that are common to active sand dunes observed by HiRISE elsewhere on Mars, including sets of small ripples crisscrossing the top of the dune. In many cases, it is the motion of these smaller ripples that drives the advance of Martian sand dunes. The dark dunes are made up of grains composed of iron-rich minerals derived from volcanic rocks on Mars, unlike the pale quartz-rich dunes typical of Earth.

This image clearly shows the dark sand situated on top of the pale TAR network, indicating that the sand dunes are younger than the TARs. Moreover, the fresh appearance of the sand dunes suggest that they are currently active, and may help shape the unusual TAR morphology by sandblasting the TARs in the present day environment.

Photo credit: NASA/JPL/University of Arizona

Dunes in Herschel Crater

This VIS image shows dunes in and around a crater located on the floor of the much larger Herschel Crater.

Orbit Number: 51566 Latitude: -14.3607 Longitude: 128.67 Instrument: VIS Captured: 2013-07-29 21:05

Photo credit: NASA/JPL-Caltech/Arizona State University

Brain Terrain in Deuteronilus Mensae

Scientists now know that Mars has a lot more ice than once thought. Many lobate features are now known to be almost pure ice, like glaciers on the Earth.

We still don't know for sure if these Martian ice deposits flow like Earth's glaciers. Knowing how fast they flow (if at all!) would help us understand more about the climate of Mars and how it has changed over time.

This image shows one of these icy lobate features wrapping around a small hill. There is an unusual texture on the ice at the base of this hill that people have called “brain terrain.” This strange-looking surface might be related to flow of the ice, but we still don't have a definite explanation for this mystery.

This is a stereo pair with ESP_032875_2195.

Photo credit: NASA/JPL/University of Arizona

Note: This location is on the edge between Arabia Terra to the south and Deuteronilus Mensae to the north.

Dunes in Bogia Crater

This VIS image shows the dunes on the floor of Bogia Crater, a crater in Hellas Planitia.

Orbit Number: 51480 Latitude: -44.3424 Longitude: 83.1185 Instrument: VIS Captured: 2013-07-22 19:25

Photo credit: NASA/JPL-Caltech/Arizona State University

Sinuous Ridge in Medusae Fossae

At this location is an exceptionally long sinuous ridge, possibly an inverted fluvial feature, that cuts across newly mapped geologic units of the Medusae Fossae Formation.

In the eastern part of the image, the sinuous ridge appears in a manner that suggests erosion of the surrounding landscape. Interestingly, this fluvial feature has no elevation within and to the west location, indicating that fluvial activity may have occurred within this material before widespread erosion.

With HiRISE resolution, we might be able to have more information on the timing of fluvial activity and its relationship to the history of the Medusa Fossae formation.

Photo credit: NASA/JPL/University of Arizona

Note: For more information, see PIA17574: Sinuous Ridge Cutting Across Geologic Units of the Medusae Fossae Formation.

Candor Chasma

This VIS image shows a portion of Candor Chasma.

Orbit Number: 51473 Latitude: -6.36614 Longitude: 290.738 Instrument: VIS Captured: 2013-07-22 05:23

Photo credit: NASA/JPL-Caltech/Arizona State University

Darwin Outcrop at Waypoint 1

For at least a couple of days, the science team of NASA's Mars rover Curiosity is focused on a full-bore science campaign at a tantalizing, rocky site informally called "Darwin."

Curiosity arrived in the vicinity of Darwin last week after its longest drive yet. The rover rolled closer to Darwin in recent days to lay its "contact science" instruments on the bedrock itself for in-depth mineral and chemical composition analysis.

Darwin and other rocks in the area first were seen in images taken from an orbiting spacecraft. The region was chosen as "Waypoint 1" because it appears to expose layers of rock that could reveal the inner makeup and history of the plains on the floor of Gale Crater, including any flows of water that laid these materials down in the past. Analysis of Darwin may provide evidence of whether and how water played a role in the layering of rocks in this region.

This view of Darwin was taken with the left eye of the Mast Camera (Mastcam) on Curiosity during the 390th Martian day, or sol, of the rover's work on Mars (Sept. 10, 2013).

Photo credit: NASA/JPL-Caltech/Malin Space Science Systems

Coprates Chasma

Today's VIS image is further west from yesterday's image. This image is near the margin between Coprates Chasma and Melas Chasma.

Orbit Number: 51423 Latitude: -12.124 Longitude: 291.311 Instrument: VIS Captured: 2013-07-18 02:40

Photo credit: NASA/JPL-Caltech/Arizona State University

Coprates Chasma

This VIS image shows part of Coprates Chasma, which is just one part of the extensive Valles Marineris canyon system.

Orbit Number: 51348 Latitude: -12.7902 Longitude: 293.216 Instrument: VIS Captured: 2013-07-11 22:34

Photo credit: NASA/JPL-Caltech/Arizona State University

Gullied Massif in the Nereidum Montes

This observation shows a beautiful example of gullies in a massif in Nereidum Montes, located in Argyre Planitia, one of the largest impact basins on Mars.

The purpose of acquiring this full-resolution image of these gullies was to take a closer look at where they are originating from in the massif wall. If we can answer that, we might be able to learn what were the processes that actually formed these gullies. In this particular region, there might be indications of a glacial past.

Nereidum Montes extends approximately 1150 kilometers, and was named by the noted Greek astronomer Eugène Michel Antoniadi (1870-1944).

Photo credit: NASA/JPL/University of Arizona

Slope Lineae along Coprates Chasma Ridge

The formation of "recurring slope lineae" is a fascinating process on Mars that we're just beginning to investigate, and one that we've imaged before in Palikir Crater.

These RSLs show up in the spring and fade in the winter. Their presence might be due to briny water, and it opens up the door to taking a fresh look at other possible RSL candidates. This observation was done to accomplish just that: to re-image a previously photographed area that might confirm if this a candidate for RSL.

When HiRISE re-images an area, we try to match the exact lighting as before, in order to see any differences. Along with a stereo pair and resulting anaglyph, our understanding of the terrain is more complete.

Photo credit: NASA/JPL/University of Arizona