New column simulations for the Viking landers: Winds, fog, frost, adsorption?

Hannu Savijärvi, Mark Paton, Ari-Matti Harri

Forskningsoutput: TidskriftsbidragArtikelVetenskapligPeer review

Sammanfattning

Boundary layer simulations are shown for the first sols of the two Viking landers (VL1, VL2) on Mars. The column model (with cloud/radiation interaction and Prandtl slope wind terms), used successfully for Phoenix and Curiosity, is equipped here with an adsorption-diffusion scheme for water vapor transport in porous regolith. The model's 1.6 m temperatures and winds are quite close to those observed by the two landers; in particular the weak summer slope winds of VL2 are excellently reproduced.

The model predicts for both sites diffusion and adsorption of water into regolith in the evening, very thin ground frost deposition from about midnight, and an early morning fog with an inflection in T1.6 m slightly weaker than observed. At the moister VL2 site fog increases optical depth as observed. Fogs and frosts sublimate away after sunrise, allowing desorption and diffusion of water off the sun-heated regolith. For porosity of 22% column water is approximately conserved from sol to sol at both sites with only little diurnal variation, as the depleted layer of air moisture is quite shallow.

In simulations without adsorption frost forms early and it grows thick. At VL2 fog now forms earlier and the jump in optical depth is larger than observed. At the drier VL1 fog still forms nearly as with adsorption, so observations could also be explained without adsorption. On the other hand VL1 certainly landed onto porous regohth and frost was not observed. Hence it is suggested that adsorption is likely at both VL sites in summer. (C) 2017 Elsevier Inc. All rights reserved.

Originalspråkengelska
TidskriftIcarus
Volym310
Sidor (från-till)48-53
Antal sidor6
ISSN0019-1035
DOI
StatusPublicerad - aug 2018
MoE-publikationstypA1 Tidskriftsartikel-refererad

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Savijärvi, Hannu ; Paton, Mark ; Harri, Ari-Matti. / New column simulations for the Viking landers : Winds, fog, frost, adsorption?. I: Icarus. 2018 ; Vol. 310. s. 48-53.
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title = "New column simulations for the Viking landers: Winds, fog, frost, adsorption?",
abstract = "Boundary layer simulations are shown for the first sols of the two Viking landers (VL1, VL2) on Mars. The column model (with cloud/radiation interaction and Prandtl slope wind terms), used successfully for Phoenix and Curiosity, is equipped here with an adsorption-diffusion scheme for water vapor transport in porous regolith. The model's 1.6 m temperatures and winds are quite close to those observed by the two landers; in particular the weak summer slope winds of VL2 are excellently reproduced.The model predicts for both sites diffusion and adsorption of water into regolith in the evening, very thin ground frost deposition from about midnight, and an early morning fog with an inflection in T1.6 m slightly weaker than observed. At the moister VL2 site fog increases optical depth as observed. Fogs and frosts sublimate away after sunrise, allowing desorption and diffusion of water off the sun-heated regolith. For porosity of 22{\%} column water is approximately conserved from sol to sol at both sites with only little diurnal variation, as the depleted layer of air moisture is quite shallow.In simulations without adsorption frost forms early and it grows thick. At VL2 fog now forms earlier and the jump in optical depth is larger than observed. At the drier VL1 fog still forms nearly as with adsorption, so observations could also be explained without adsorption. On the other hand VL1 certainly landed onto porous regohth and frost was not observed. Hence it is suggested that adsorption is likely at both VL sites in summer. (C) 2017 Elsevier Inc. All rights reserved.",
keywords = "114 Physical sciences, Mars, Climate Mars, Surface meteorology, BOUNDARY-LAYER, WATER CYCLE, GALE CRATER, MARS, REGOLITH, SITE, EXCHANGE, SENSOR",
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New column simulations for the Viking landers : Winds, fog, frost, adsorption? / Savijärvi, Hannu; Paton, Mark; Harri, Ari-Matti.

I: Icarus, Vol. 310, 08.2018, s. 48-53.

Forskningsoutput: TidskriftsbidragArtikelVetenskapligPeer review

TY - JOUR

T1 - New column simulations for the Viking landers

T2 - Winds, fog, frost, adsorption?

AU - Savijärvi, Hannu

AU - Paton, Mark

AU - Harri, Ari-Matti

PY - 2018/8

Y1 - 2018/8

N2 - Boundary layer simulations are shown for the first sols of the two Viking landers (VL1, VL2) on Mars. The column model (with cloud/radiation interaction and Prandtl slope wind terms), used successfully for Phoenix and Curiosity, is equipped here with an adsorption-diffusion scheme for water vapor transport in porous regolith. The model's 1.6 m temperatures and winds are quite close to those observed by the two landers; in particular the weak summer slope winds of VL2 are excellently reproduced.The model predicts for both sites diffusion and adsorption of water into regolith in the evening, very thin ground frost deposition from about midnight, and an early morning fog with an inflection in T1.6 m slightly weaker than observed. At the moister VL2 site fog increases optical depth as observed. Fogs and frosts sublimate away after sunrise, allowing desorption and diffusion of water off the sun-heated regolith. For porosity of 22% column water is approximately conserved from sol to sol at both sites with only little diurnal variation, as the depleted layer of air moisture is quite shallow.In simulations without adsorption frost forms early and it grows thick. At VL2 fog now forms earlier and the jump in optical depth is larger than observed. At the drier VL1 fog still forms nearly as with adsorption, so observations could also be explained without adsorption. On the other hand VL1 certainly landed onto porous regohth and frost was not observed. Hence it is suggested that adsorption is likely at both VL sites in summer. (C) 2017 Elsevier Inc. All rights reserved.

AB - Boundary layer simulations are shown for the first sols of the two Viking landers (VL1, VL2) on Mars. The column model (with cloud/radiation interaction and Prandtl slope wind terms), used successfully for Phoenix and Curiosity, is equipped here with an adsorption-diffusion scheme for water vapor transport in porous regolith. The model's 1.6 m temperatures and winds are quite close to those observed by the two landers; in particular the weak summer slope winds of VL2 are excellently reproduced.The model predicts for both sites diffusion and adsorption of water into regolith in the evening, very thin ground frost deposition from about midnight, and an early morning fog with an inflection in T1.6 m slightly weaker than observed. At the moister VL2 site fog increases optical depth as observed. Fogs and frosts sublimate away after sunrise, allowing desorption and diffusion of water off the sun-heated regolith. For porosity of 22% column water is approximately conserved from sol to sol at both sites with only little diurnal variation, as the depleted layer of air moisture is quite shallow.In simulations without adsorption frost forms early and it grows thick. At VL2 fog now forms earlier and the jump in optical depth is larger than observed. At the drier VL1 fog still forms nearly as with adsorption, so observations could also be explained without adsorption. On the other hand VL1 certainly landed onto porous regohth and frost was not observed. Hence it is suggested that adsorption is likely at both VL sites in summer. (C) 2017 Elsevier Inc. All rights reserved.

KW - 114 Physical sciences

KW - Mars

KW - Climate Mars

KW - Surface meteorology

KW - BOUNDARY-LAYER

KW - WATER CYCLE

KW - GALE CRATER

KW - MARS

KW - REGOLITH

KW - SITE

KW - EXCHANGE

KW - SENSOR

U2 - 10.1016/j.icarus.2017.11.007

DO - 10.1016/j.icarus.2017.11.007

M3 - Article

VL - 310

SP - 48

EP - 53

JO - Icarus

JF - Icarus

SN - 0019-1035

ER -