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| Titel |
Hydraulic modeling of an interior channel identified inside a Martian Valley |
| VerfasserIn |
Emanuele Baratti, Maurizio Pajola, Marcello Coradini, Alberto Montanari, David Pieri, Karen McBride |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250095904
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| Publikation (Nr.) |
 EGU/EGU2014-11380.pdf |
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| Zusammenfassung |
| Constraining the amount of water flowing on the surface of Mars during the ancient
hydrological activity of the planet is one of the fundamental and crucial aspects to understand
its paleohydrology. Within this work, a detailed hydraulic study of an interior channel is
presented. The river reach is located in the Memnonia quadrangle between 166°0’0"w and
168°0’0"w longitude and between 8°0’0"s and 9°0’0"s latitude. The Mars Express
high-resolution stereo camera digital elevation model, HRSC DEM, H31850000DA4,
presents a spatial resolution of 75 m and it was used to characterize the geometry of the
interior channel. Geomorphic evidences (i.e. flood terraces) were used to identify the
probable bank-full level. In particular, we found out that the channel appears to be
characterized by two different terracing levels. The river reach segment is 10 km
long and averagely 1 km wide. The paleoriver bed presents a complex topography,
characterized by significant changes in slope. We used a hydraulic model capable to
perform one-dimensional water surface profile calculations for steady gradually varied
flow in natural channels. At each cross section we computed the water level by
solving the energy equation or, where this was not considered applicable, by using the
momentum equation. The identified terracing levels were used to constrain the
water discharge flowing on the surface and the roughness coefficient of the surface
(the latter, as well as the energy and momentum equations, being adapted to the
Martian gravity). By applying a Monte Carlo procedure, the relative frequency
of the most probable discharge and roughness coefficient for both bankfull levels
was derived. Hints on the grain size distribution are also presented. Regarding the
lower bankfull levels, we obtained a median value of stream discharge and Manning
roughness coefficient equal to 17400m3s-1 and 0.08m-1-3s. When considering the
upper terracing levels our methodology indicated a median value of 140000m3s-1
and 0.16m-1-3s, for the discharge and the roughness coefficient, respectively. |
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