The vertical distribution of Mars water vapor

Davies, Donald W.

doi:10.1029/jb084ib06p02875

Cited by 92 publications

(51 citation statements)

References 8 publications

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“…Viking (Davies 1979) and ground-based observations (Barker 1976(Barker , 1998Sprague et al 1996) made with diurnal coverage have found an apparent diurnal trend with water vapor abundance low in early morning and late afternoon. Several impli- 1996-1977 and open circles 1998-1999.…”

Section: Results: High North Latitude Water Vapor Abundancesmentioning

confidence: 94%

Water Vapor Abundances over Mars North High Latitude Regions: 1996–1999

Sprague

Hunten

Hill

et al. 2001

Icarus

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Section: Results: High North Latitude Water Vapor Abundancesmentioning

confidence: 94%

Water Vapor Abundances over Mars North High Latitude Regions: 1996–1999

Sprague

Hunten

Hill

et al. 2001

Icarus

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“…The derived O 2 mixing ratio was (1.1-1.3) × 10 −3 . Aerosol extinction was neglected in all retrievals of the O 2 abundance, and this may result the underestimation of O 2 (Davies, 1979). The Viking mass spectrometers (Owen et al, 1977) gave the O 2 mixing ratio of (1-4) × 10 −3 , that is, (2.5 ± 1.5) × 10 −3 .…”

Section: Global-mean Modelsmentioning

confidence: 99%

Photochemistry of the martian atmosphere: Seasonal, latitudinal, and diurnal variations

Krasnopolsky

2006

Icarus

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“…Certainly, condensation appeared to limit the vertical extent of most of the water vapor in an atmospheric column [Davies, 1979;Jakosky, 1985], and there appeared to be a lowering of the water ice cloud base in northern spring and summer [Jaquin et al, 1986] that could affect the Mars water cycle by amplifying seasonal exchange between the atmosphere and surface [Kahn, 1990]. It was also suggested that water condensation on dust grains could remove dust from the atmosphere immediately below detached hazes.…”

Section: Paper Number 1999je001133mentioning

confidence: 99%

Viking era water‐ice clouds

Tamppari¹,

Zurek²,

Paige³

2000

J. Geophys. Res.

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Abstract. We have spatially and temporally mapped water ice clouds on Mars for 1.25 Martian years using the Viking infrared thermal mapper (IRTM) data. Our technique compares brightness temperatures in the 11 and 20/xm IRTM channels, utilizing the 11 /xm water ice absorption feature. A complication arises because of the surface nonunit and wavelength-dependent emissivities. We developed a technique for removal of this effect. Using a surface thermal model, we calculated brightness temperatures and their differences for the IRTM channels resulting from the surface emissivity effect alone. These were then subtracted from the measured brightness temperatures, yielding brightness temperature differences dominated by atmospheric effects. The ability to identify water ice clouds in the infrared provides potential new information about particle size and physical processes by comparing these clouds to those seen in visible wavelengths. We found that water ice clouds were more widespread and frequent during the Viking period than had been previously recognized, with the northern spring and summer being the cloudlest periods on Mars. We interpret some of the identified cloudy zones as the southern and northern solstice season upwelling branches of the Hadley cell, although these were shifted 15ø-20 ø southward from model predictions. Additionally, the transition between the two branches occurred later in time than in the model predictions. We observed the extension of the north polar hood below 60øN in longitudes 120ø-200 ø. We did not find evidence for a south polar hood north of 60øS nor any evidence for interannual variability within our limited data set. Despite the early observations that water-ice clouds existed and were on occasion widespread, these clouds were not thought to play a key role in the atmospheric circulation, and their role in the Martian water cycle was uncertain. The amount of water involved in the formation of the observed ice clouds was small, and so, the latent heating associated with them was negligible, especially when compared to the direct atmospheric heating that could be achieved with even minor amounts of dust suspended in the atmosphere . Because the most widespread cloud hazes appeared to be relatively thin, radiative effects also were neglected, away from the polar regions and other than for surface fogs. proposed that water ice cloud formation provided in some seasons a global control of the vertical distribution of atmospheric dust. By removing dust and its associated solar heating, ice condensation could play a major role in the global circulation and in the transport of dust as well as water.In this hypothesis the present eccentricity of the orbit of Mars and the occurrence of aphelion during late northern spring radiatively leads to colder temperatures during northern spring and summer, resulting in more frequent and widespread water ice clouds. The formation of these clouds causes gravitational settling of ice particles in the rising branch of a cross- 4087

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The vertical distribution of Mars water vapor

Cited by 92 publications

References 8 publications

Water Vapor Abundances over Mars North High Latitude Regions: 1996–1999

Water Vapor Abundances over Mars North High Latitude Regions: 1996–1999

Photochemistry of the martian atmosphere: Seasonal, latitudinal, and diurnal variations

Viking era water‐ice clouds

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