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Blobrana


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NASA Rover Finds Clues to Changes in Mars' Atmosphere

NASA's car-sized rover, Curiosity, has taken significant steps toward understanding how Mars may have lost much of its original atmosphere.
Learning what happened to the Martian atmosphere will help scientists assess whether the planet ever was habitable. The present atmosphere of Mars is 100 times thinner than Earth's.
A set of instruments aboard the rover has ingested and analysed samples of the atmosphere collected near the "Rocknest" site in Gale Crater where the rover is stopped for research. Findings from the Sample Analysis at Mars (SAM) instruments suggest that loss of a fraction of the atmosphere, resulting from a physical process favouring retention of heavier isotopes of certain elements, has been a significant factor in the evolution of the planet. Isotopes are variants of the same element with different atomic weights.
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Blobrana


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Observations show extreme pressure swings on Mars

Though a barren, life-intimidating landscape, Mars still has the most resembling weather to Earth compared to the other planets in our solar system. Recent measurements beamed by the Curiosity rover, which touched down on the martian surface a few weeks ago, have confirmed the scientists theories of extreme pressure swings. According to observations, pressure variations can be 100 times greater than those on Earth, and could potentially be the primary factor driving the massive dust storms on Mars.
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Blobrana


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Title: Rocket dust storms and detached layers in the Martian atmosphere
Authors: Aymeric Spiga, Julien Faure, Jean-Baptiste Madeleine, Anni Määttänen, François Forget

Airborne dust is the main climatic agent in the Martian environment. Local dust storms play a key role in the dust cycle; yet their life cycle is poorly known. Here we use mesoscale modelling with radiatively-active transported dust to predict the evolution of a local dust storm monitored by OMEGA on board Mars Express. We show that the evolution of this dust storm is governed by deep convective motions. The supply of convective energy is provided by the absorption of incoming sunlight by dust particles, in lieu of latent heating in moist convection on Earth. We propose to use the terminology "rocket dust storm", or conio-cumulonimbus, to describe those storms in which rapid and efficient vertical transport takes place, injecting dust particles at high altitudes in the Martian troposphere (30 to 50 km). Combined to horizontal transport by large-scale winds, rocket dust storms form detached layers of dust reminiscent of those observed with instruments on board Mars Global Surveyor and Mars Reconnaissance Orbiter. Detached layers are stable over several days owing to nighttime sedimentation being unable to counteract daytime convective transport, and to the resupply of convective energy at sunrise. The peak activity of rocket dust storms is expected in low-latitude regions at clear season, which accounts for the high-altitude tropical dust maximum unveiled by Mars Climate Sounder. Our findings on dust-driven deep convection have strong implications for the Martian dust cycle, thermal structure, atmospheric dynamics, cloud microphysics, chemistry, and robotic and human exploration.

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Blobrana


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On Mars, photographs from landing vehicles (the Viking from 1976-78 and the Pathfinder in 1997) suggested that the sky is generally a butterscotch (yellowish-brown) colour. Mars appears to have a permanent haze of dust, which remains suspended in the air after dust storms. The dust contains the mineral limonite, a brown iron oxide found on most of the Martian surface. Sky colour measurements from Viking Lander 1 have been used with computer simulations of light scattering to estimate that the dust particles contained about 1% by volume of another iron oxide mineral known as magnetite (a black, opaque material).
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Blobrana


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A glow in the Martian night throws light on atmospheric circulation

A faint, infrared glow above the winter poles of Mars is giving new insights into seasonal changes in the planet's atmospheric circulation. The tell-tale night emission was first detected in 2004 in observations made by the OMEGA imaging spectrometer on ESA's Mars Express orbiter.
Writing in a recent issue of the Journal of Geophysical Research, a team of French scientists reported on the first detection of an infrared emission above the polar regions of Mars. The emission, at a wavelength of 1.27 microns, was detected on three occasions (in 2004, 2005 and 2006) during a series of 40 observations made by OMEGA above the planet's limb.
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Blobrana


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Mars Carbon Dioxide
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Some of Mars' Missing Carbon Dioxide May be Buried

Rocks on Mars dug from far underground by crater-blasting impacts are providing glimpses of one possible way Mars' atmosphere has become much less dense than it used to be.
At several places where cratering has exposed material from depths of about 5 kilometres or more beneath the surface, observations by a mineral-mapping instrument on NASA's Mars Reconnaissance Orbiter indicate carbonate minerals.
These are not the first detections of carbonates on Mars. However, compared to earlier findings, they bear closer resemblance to what some scientists have theorised for decades about the whereabouts of Mars' "missing" carbon. If deeply buried carbonate layers are found to be widespread, they would help answer questions about the disappearance of most of ancient Mars' atmosphere, which is deduced to have been thick and mostly carbon dioxide. The carbon that goes into formation of carbonate minerals can come from atmospheric carbon dioxide.
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Blobrana


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Martian carbon monoxide
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Title: First results on martian carbon monoxide from Herschel/HIFI observations
Authors: P. Hartogh, M. I. Bcka, C. Jarchow, H. Sagawa, E. Lellouch, M. de Val-Borro, M. Rengel, A. S. Medvedev, B. M. Swinyard, R. Moreno, T. Cavalié, D. C. Lis, M. Banaszkiewicz, D. Bockelée-Morvan, J. Crovisier, T. Encrenaz, M. Küppers, L.-M. Lara, S. Szutowicz, B. Vandenbussche, F. Bensch, E. A. Bergin, F. Billebaud, N. Biver, G. A. Blake, J. A. D. L. Blommaert, J. Cernicharo, L. Decin, P. Encrenaz, H. Feuchtgruber, T. Fulton, T. de Graauw, E. Jehin, M. Kidger, R. Lorente, D. A. Naylor, G. Portyankina, M. Sánchez-Portal, R. Schieder, S. Sidher, N. Thomas, E. Verdugo, C. Waelkens, A. Lorenzani, G. Tofani, E. Natale, J. Pearson, T. Klein, C. Leinz, R. Güsten, C. Kramer

We report on the initial analysis of Herschel/HIFI carbon monoxide observations of the martian atmosphere performed between 11 and 16 April 2010. We selected the (7-6) rotational transitions of the isotopes ^{13}CO and C^{18}O at 771 and 768 GHz respectively in order to retrieve the mean vertical profile of temperature and the mean volume mixing ratio of carbon monoxide. The derived temperature profile agrees within less than 5 K with general circulation model predictions up to an altitude of 45 km, however show about 12-15 K lower values at 60 km. The carbon monoxide mixing ratio was determined to be 980 \pm 150 ppm, in agreement with the 900 ppm derived from Herschel/SPIRE observations in November 2009.

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Blobrana


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Martian Atmosphere
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DLR simulates Mars' atmosphere in Göttingen
Is the Earth the only place in our Solar System on which living organisms exist? Is there, for example, life on Mars? The goal of the European space mission ExoMars is to resolve this question. To this end, the atmosphere on Mars is being simulated at the German Aerospace Centre (Deutsches Zentrum für Luft- und Raumfahrt; DLR) in Göttingen.

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