Mars: Northern Summer Ice Cap—Water Vapor Observations from Viking 2

Farmer, C. B.; Davies, Donald W.; LaPorte, Daniel D.

doi:10.1126/science.194.4271.1339

Cited by 129 publications

(61 citation statements)

References 6 publications

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“…The Viking Orbiter Infrared Thermal Mapper (IRTM) measured summertime brightness temperatures as high as 205 K over the north perennial cap, well in excess of the 148 K sublimation temperature of C02 (Kieffer et al 1976). Concurrent atmospheric water vapor measurements confirmed that the polar atmosphere was saturated with respect to a surface reservoir of H 2 0 (Farmer et al 1976). These observations demonstrated conclusively that the composition of the volatile component of the perennial cap was water ice.…”

Section: Composition and Geologymentioning

confidence: 85%

The State and Future of Mars Polar Science and Exploration

Clifford

2000

Icarus

110

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20, 1999; revised October 25, 1999 As the planet's principal cold traps, the martian polar regions have accumulated extensive mantles of ice and dust that cover individual areas of -lo6 km2 and total as much as 3-4 km thick. From the scarcity of superposed craters on their surface, these layered deposits are thought to be comparatively young-preserving a record of the seasonal and climatic cycling of atmospheric COz, H20, and dust over the past NIO~-IO~ years..For this reason, the martian polar deposits may serve as a Rosetta Stone for understanding the geologic and climatic history of the planet--documenting variations in insolation (due to quasiperiodic oscillations in the planet's obliquity and orbital elements), volatile mass balance, atmospheric composition, dust storm activity, volcanic eruptions, large impacts, catastrophic floods, solar luminosity, supernovae, and perhaps even a record of microbial life. Beyond their scientific value, the polar regions may soon prove important for another reason-providing a valuable and accessible reservoir of water to support the long-term human exploration of Mars. In this paper we assess the current state of Mars polar research, identify the key questions that motivate the exploration of the polar regions, discuss the extent to which current missions will address these questions, and speculate about what additional capabilities and investigations may be required to address the issues that remain outstanding.

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Section: Composition and Geologymentioning

confidence: 85%

The State and Future of Mars Polar Science and Exploration

Clifford

2000

Icarus

110

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“…Thus, the two polar regions differ profoundly not only in regional height, but also in regional morphology and the geographical extent of the permanent cap. Furthermore, the southern rather than the northern permanent cap proved to be the site of excess solid CO 2 required for continuing CO 2 solid-vapor balance on Mars (Farmer et al 1976, Kieffer 1979, Paige et al 1990. Plaut et al (1988) argued that the crater density on the SPLD suggests an average surface age of at least 120 million years, significantly older than previously thought.…”

Section: A the Puzzling Record Of The Martian Polar Depositsmentioning

confidence: 97%

Preliminary Geological Assessment of the Northern Edge of Ultimi Lobe, Mars South Polar Layered Deposits

Murray

Koutnik

Byrne

et al. 2001

Icarus

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“…Brightness temperatures over most of the cap during late 1976, when it was summer in the north, were near 205°K, close to the frost point of water in a well-mixed atmosphere containing only a few tens of precipitable (pr) micrometers of water (Kieffer et al, 1976). In addition, relatively large amounts of water vapor (80-100 pr /~m) were in the atmosphere over the poles (Farmer et al, 1976), indicating that the atmosphere was close to saturation. Half a Martian year later, during southern summer, similar measurements were made over the southern cap.…”

Section: Climatic Variations As a Cause Of The Layeringmentioning

confidence: 98%

Periodic climate change on Mars: Review of evidence and effects on distribution of volatiles

Carr

1982

Icarus

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The polar regions of Mars preserve, in both their layering and their topography, a record of recent climate changes. Because of the coincidence of the growth of the northern seasonal cap with global dust storms, dust may be currently accumulating on the northern cap, but conditions at the poles will alternate with the precessional cycle. Deposition is also modulated by changes in eccentricity and obliquity, which interact complexly, affecting initiation of global dust storms, the stability of volatiles at the surface, and global wind regimes. Formation of spiral valleys and low undulations on the surface of the layered deposits may result from preferential sublimation of volatiles on sunward-facing slopes and condensation on the adjacent flats, with the rates also modulated by astronomically caused insolation variations. Lack of impact craters on the surface and lack of interruption of the layers by impact scars suggest that the polar deposits are no more than a few million years old. Older deposits may have been periodically removed, as indicated by etch-pitted terrain at the south pole and by superposition relations around the periphery of the present layered deposits. Evidence of ancient periodic climate changes that occurred before formation of the present layered terrain is fragmentary but includes pedestal craters, parallel moraine-like ridges, and etched ground at high latitudes. Perturbation of the orbital motions also results in adsorption and desorption of volatiles in the regolith, which leads to variations in atmospheric pressure and partial dehydration of the equatorial near-surface materials.

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Mars: Northern Summer Ice Cap—Water Vapor Observations from Viking 2

Cited by 129 publications

References 6 publications

The State and Future of Mars Polar Science and Exploration

The State and Future of Mars Polar Science and Exploration

Preliminary Geological Assessment of the Northern Edge of Ultimi Lobe, Mars South Polar Layered Deposits

Periodic climate change on Mars: Review of evidence and effects on distribution of volatiles

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