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Remote Sensing of the Icy Moons of Jupiter - Galileo mission
Tomášková, Eliška ; Červená, Lucie (advisor) ; Potůčková, Markéta (referee)
The bachelor's thesis focuses on the processing and analysis of Galileo SSI and NIMS image data, which captures the Tyre region of Europa and the Kittu region of Ganymede. Initially, the problems of data retrieval from the PDS archive and its thorough radiometric and geometric corrections are addressed. Pre-processing, visualization, and subsequent data analysis were conducted using the POW tool, ISIS3, ENVI, and ArcGIS Pro software. Based on the principal component analysis of the NIMS data, the two most different end-members representing ice and "salt" were selected. These were then used in Linear Spectral Unmixing, which provided information on the spatial distribution and relative concentrations of the "salt" end-member in the study areas. The outputs from the hyperspectral data were projected over the higher spatial resolution data to examine relationships between surface morphology and composition. The resulting SSI, Voyager, and NIMS composites suggest a strong correlation between the salt component and areas with disrupted ice crust on Jupiter's icy moons. Furthermore, unsupervised classification of SSI images capturing the Tyre crater was performed and showed similar results to Linear Spectral Unmixing of the NIMS data. Additionally, significant differences in reflectance values between...
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Tidal heating in icy bodies of the Solar System
Dvořáková, Nela ; Čadek, Ondřej (advisor) ; Čížková, Hana (referee)
1 Abstract The thesis concerns with icy moons and the computation of the heat production which is generated by the effect of tidal forces. The text primarily focuses on the behaviour of viscosity in the ice shell for variable ice shell thickness. Viscosity decreases exponentially as the temperature of ice increases. We also study the viscosity and heat dependence on the size of an ice grain in range of 10−5 m - 10−1 m and the amount of stress in range of 103 Pa - 107 Pa. Computation was realized using a provided program and the results of all models are represented in form of a heat map and further studied. Primarily we discuss the heat balance of the moon Europa and Enceladus. 1
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The effect of a subsurface ocean on the heat transfer in an icy moon
Kvorka, Jakub ; Čadek, Ondřej (advisor) ; Souček, Ondřej (referee)
Successful space missions to Jupiter and Saturn provided important data bearing information about topography and internal structure of icy bodies in the outer Solar System. One of the possibilities how to explain the observed topography of an icy moon is to assume the existence of subsurface reservoir of liquid water transferring heat from the rocky core to icy crust causing its deformation. In this thesis, we develop a computer program to model the convective heat transfer in a rotating liquid shell, which we use to analyze heat flux anomalies on the top of the subsurface ocean. The results obtained for Titan are in agreement with those independently obtained from modelling the icy crust.
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Deformation and thermal evolution of the ice shell on Enceladus
Kvorka, Jakub ; Čadek, Ondřej (advisor) ; Souček, Ondřej (referee)
In the last two decades, successful space missions to Jupiter and Saturn provi- ded important data bearing information about topography and internal structure of icy bodies in the outer Solar System. Some of these bodies contain subsurface reservoirs of liquid water in contact with an outer shell made of solid ice. One of the possibilities how to explain the observed topography of a moon is to use its thermal production as the energy source that produces deformation of the ice crust covering the body. In this study, we develop a simplified mathematical mo- del of thermal-mechanical evolution of the ice crust including the effect of phase transition at its bottom boundary. The appropriate system of partial differential equations is coded in Fortran95 and used to study the surface features developed in response to heat flux anomalies imposed on the top of the subsurface ocean. The results obtained for Enceladus, Europa and Titan show that the observed topography of these moons can be explained only for a large grain size and the ice crust behaving elastically near the upper boundary. 1
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Numerické modelování proudění vody v nitru ledových těles
Krivoš, Martin ; Čadek, Ondřej (advisor) ; Hanyk, Ladislav (referee)
Title: Numerical modeling of liquid water flows in ice bodies' interiors Author: Martin Krivoš Department: Department of Geophysics Supervisor: prof. RNDr. Ondřej Čadek, CSc., Department of Geophysics Abstract: We studied the flow induced by water jets in the subsurface oceans on the Solar system moons - Europa and Enceladus. In water plumes of Enceladus Cassini spacecraft detected small silica particles with radii ≈ 6 − 9 nm. As shown by experiments, these particles grow in size with time spent in the ocean. The small size of particles suggests that the material transport from the the jets on the oceanic floor to the source of the plume at the moon's surface is highly efficient. In the thesis we investigate the characteristic transport time by solving the Navier-Stokes equation for incompressible fluid. For this purpose we have developed a Fortran program in two-dimensional Cartesian geometry based on the finite-difference staggered-grid method. Another program, using the second order Runge-Kutta method, was written to reconstruct the trajectories of the particles in the ocean. Using these tools we estimated the effectiveness of material transport under different conditions, namely presence of global lateral flow, width of the water jet, the Reynolds number and the number of jets. Keywords: Navier-Stokes equation,...
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Flow of a subsurface ocean in shallow water approximation
Šafin, Jakub ; Čadek, Ondřej (advisor) ; Velímský, Jakub (referee)
In this thesis, we deal with the flow of a subsurface ocean in the so-called shallow water approximation. From the equations describing general flow of an incompressible fluid, we obtain simplified equations, applicable to a shallow global ocean on a rotating sphere. Based on these equations, we develop a program that can be used to model the flow of an ocean in 2D. We create short simulations of the flow on two icy moons, Europa and Enceladus, forced by the eccentricity and obliquity tidal potentials. The existence of subsurface oceans has been demonstrated on icy moons of outer planets; the mechanism which keeps them from freezing has remained unclear until now. Based on the flow simulations, we attempt to estimate the energy dissipation due to bottom friction. Powered by TCPDF (www.tcpdf.org)
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Tidal heating in icy bodies of the Solar System
Dvořáková, Nela ; Čadek, Ondřej (advisor) ; Čížková, Hana (referee)
1 Abstract The thesis concerns with icy moons and the computation of the heat production which is generated by the effect of tidal forces. The text primarily focuses on the behaviour of viscosity in the ice shell for variable ice shell thickness. Viscosity decreases exponentially as the temperature of ice increases. We also study the viscosity and heat dependence on the size of an ice grain in range of 10−5 m - 10−1 m and the amount of stress in range of 103 Pa - 107 Pa. Computation was realized using a provided program and the results of all models are represented in form of a heat map and further studied. Primarily we discuss the heat balance of the moon Europa and Enceladus. 1
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