Mars south polar spring and summer behavior observed by TES: Seasonal cap evolution controlled by frost grain size

Kieffer, H. H.; Titus, T. N.; Mullins, K. F.; Christensen, P. R.

doi:10.1029/1999je001136

Cited by 220 publications

(312 citation statements)

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“…Eluszkiewicz [1993] predicted the presence of both nonporous (slab-like) CO 2 ice and more porous, fluffy frost, a prediction confirmed by subsequent analyses [Kieffer et al, 2000;Titus et al, 2001] (for completeness, we note that according to Langevin et al [2006], dust coating can also mimic the slab ice behavior). A fluffy texture can be distinguished from a slab layer by the shape of the 25-mm band of solid CO 2 [Hansen, 1997] seen in the TES spectra, with large band depth BD 25 indicative of high porosity.…”

Section: Tes Datamentioning

confidence: 66%

“…Specifically, we use 10 cm À1 radiances from the TES detector 1, restricting ourselves to the wave number range 222 -900 cm À1 (i.e., excluding the first five TES channels, due to obvious instrumental artifacts, and the shorter wavelength channels that have low signal-to-noise ratios at the cold polar temperatures). The zero-radiance level of the spectra available from the PDS has been corrected using software (provided by J. Bandfield and T. Titus, personal communication, 2008) that accounts for an error caused by variations of instrument radiance within the field of view with changing mirror-pointing angle Kieffer et al, 2000]. This correction has led to more physical results for the surface emissivity (see section 3).…”

Section: Tes Datamentioning

confidence: 99%

“…A fluffy texture can be distinguished from a slab layer by the shape of the 25-mm band of solid CO 2 [Hansen, 1997] seen in the TES spectra, with large band depth BD 25 indicative of high porosity. BD 25 is defined as the fractional drop in the measured band radiance relative to the expected blackbody radiance at the brightness temperature of adjacent continua [Kieffer et al, 2000] …”

Section: Tes Datamentioning

confidence: 99%

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Atmospheric and surface retrievals in the Mars polar regions from the Thermal Emission Spectrometer measurements

Eluszkiewicz¹,

Moncet²,

Shephard³

et al. 2008

J. Geophys. Res.

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[1] Retrievals of atmospheric temperatures, surface emissivities, and dust opacities in the Mars polar regions from the Thermal Emission Spectrometer (TES) spectra are presented. The retrievals correspond to two types of spectra, characterized by small and large band depths BD 25 in the 25-mm band of solid CO 2 . These two types of spectra have previously been identified with locations covered by slab ice and fluffy CO 2 frost, respectively. Above the first atmospheric scale height, there is a correlation between the degree of saturation in the retrieved atmospheric temperatures and the two types of surface, with the high BD 25 spectra (''cold spots'') showing larger supersaturations around 1 mbar. This supports the hypothesis that cold spots correspond to locations with potential or actual atmospheric precipitation. Furthermore, the retrieved temperature profiles exhibit a warming above 1 mbar (15 km), which appears real even when the limited number of independent pieces of information from the measurement ($3) and coarse vertical resolution of the TES instrument above 15 km are considered. The spectral shape of the retrieved surface emissivities in the cold spot locations is consistent with modeling results attributing high BD 25 to porosity. For the low BD 25 spectra, the retrieved emissivities are spectrally flat but significantly less than unity (0.8-0.9). The cause of these spectrally uniform deviations from blackbody behavior (which are not supported by modeling) remains to be investigated, with a noticeable reduction in the deviation from the blackbody behavior achieved through a zero-radiance-level correction to the TES spectra available from the Planetary Data System.

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Section: Tes Datamentioning

confidence: 66%

Section: Tes Datamentioning

confidence: 99%

Section: Tes Datamentioning

confidence: 99%

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Atmospheric and surface retrievals in the Mars polar regions from the Thermal Emission Spectrometer measurements

Eluszkiewicz¹,

Moncet²,

Shephard³

et al. 2008

J. Geophys. Res.

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“…Laboratory studies, as well as TES and MOC observations, suggest that the thermophysical and radiative properties of COz are contributing to a seasonal polar cap behavior more complex than previously imagined (Hansen 1999, Kieffer et al 2000, James et al 2000. As the seasonal south polar cap receded during the first southern spring observed by the Mars Global Surveyor, a prominent and variegated dark region developed within the cap (--75"-85"S, 150"-310°W) that had an albedo similar to that of bare martian soil but a surface temperature that, while several degrees warmer than the surrounding cap, remained too cold to be ice-free.…”

Section: Seasonal and Climatic Evolutionmentioning

confidence: 99%

“…In order to match the Viking Lander pressure data, models need to suppress the emissivity of the north cap relative to the south cap. A reduced emissivity could be due to the unusual properties of pure C02 ice crystals on the surface, or to the observed presence of C02 ice clouds in the atmosphere (Bell et al 1996, Hansen 1999, Kieffer et al 2000.…”

Section: Seasonal and Climatic Evolutionmentioning

confidence: 99%

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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Material ejection by the cold jets and temperature evolution of the south seasonal polar cap of Mars from THEMIS/CRISM observations and implications for surface properties

et al. 2013

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[1] As the seasonal CO 2 ice polar caps of Mars retreat during spring, dark spots appear on the ice in some specific regions. These features are thought to result from basal sublimation of the transparent CO 2 ice followed by ejection of regolith-type material, which then covers the ice. We have used Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) reflectance data, Thermal Emission Imaging System (THEMIS) visible images, and THEMIS-derived temperature retrievals along with a thermal numerical model to constrain the physical and compositional characteristics of the seasonal cap for several areas exhibiting dark spots at both high spatial and temporal resolutions. Data analysis suggests an active period of material ejection (before solar longitude (Ls) 200), accumulation around the ejection points, and spreading of part of the ejected material over the whole area, followed by a period where no significant amount of material is ejected, followed by complete defrosting ( Ls 245). Dark material thickness on top of the CO 2 ice is estimated to range from a few hundreds of microns to a few millimeters in the warmest spots, based on numerical modeling combined with the observed temperature evolution. The nature of the venting process and the amount of material that is moved lead to the conclusion that it could have an important impact on the surface physical properties.Citation: Pilorget, C., C. S. Edwards, B. L. Ehlmann, F. Forget, and E. Millour (2013), Material ejection by the cold jets and temperature evolution of the south seasonal polar cap of Mars from THEMIS/CRISM observations and implications for surface properties,

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Mars south polar spring and summer behavior observed by TES: Seasonal cap evolution controlled by frost grain size

Abstract: Abstract. Thermal Emission Spectrometer (TES) observations of the recession

Cited by 220 publications

References 59 publications

Atmospheric and surface retrievals in the Mars polar regions from the Thermal Emission Spectrometer measurements

Atmospheric and surface retrievals in the Mars polar regions from the Thermal Emission Spectrometer measurements

The State and Future of Mars Polar Science and Exploration

Material ejection by the cold jets and temperature evolution of the south seasonal polar cap of Mars from THEMIS/CRISM observations and implications for surface properties

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