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1.
Yu. G. Shkuratov V. G. Kaydash L. V. Starukhina C. M. Pieters 《Solar System Research》2007,41(3):177-185
From the Clementine UVVIS imagery of the lunar surface, the abundance of agglutinates in the lunar regolith and their composition in terms of FeO and Al2O3 oxides have been predicted. Data on the spectral, chemical, and mineralogic measurements of about 30 lunar soil samples from the Lunar Samples Characterization Consortium (LSCC) collection were used. The fulfilled prognosis confirms that the mare agglutinates are enriched in Al2O3 and depleted of FeO, while the highland agglutinates are depleted of Al2O3 and enriched in FeO. This behavior can be caused by the global transport of the lunar surface material induced by cosmogenic factors. 相似文献
2.
We report results of polarimetric imaging observations of Mars with the Hubble Space Telescope during the 2003 opposition. Through careful calibration, the observations with the ACS camera allow measurements of the polarization degree with an absolute accuracy better than 0.5% and detection of features with polarization degree contrast as small as 0.2%. The general distribution of linear polarization parameters over the Mars disk and their dependence on phase angle and wavelength are well explained qualitatively by a combination of scattering separately by the martian surface and atmosphere. We have discovered transient polarization phenomena interpreted as clouds that are best observed in ultraviolet light. These clouds are optically thin but strongly polarizing, and their origin may be related to atmospheric ice condensation processes. 相似文献
3.
The winds of Mars at the water cloud level are measured by tracking cloud features in sequential high-resolution Hubble Space Telescope UV images for 5 days during the perihelion season in 2003. Global circulation model (GCM) predictions are in general agreement with the observations for the zonal wind component, but reveal significant differences for the meridional component. 相似文献
4.
Prognosis of TiO2 abundance in lunar soil using a non-linear analysis of Clementine and LSCC data 总被引：1，自引：0，他引：1
Viktor V. Korokhin Vadym G. Kaydash Dmitry G. Stankevich 《Planetary and Space Science》2008,56(8):1063-1078
We suggest a technique to determine the chemical and mineral composition of the lunar surface using artificial neural networks (ANNs). We demonstrate this powerful non-linear approach for prognosis of TiO2 abundance using Clementine UV-VIS mosaics and Lunar Soil Characterization Consortium data. The ANN technique allows one to study correlations between spectral characteristics of lunar soils and composition parameters without any restrictions on the character of these correlations. The advantage of this method in comparison with the traditional linear regression method and the Lucey et al. approaches is shown. The results obtained could be useful for the strategy of analyzing lunar data that will be acquired in incoming lunar missions especially in case of the Chandrayaan-1 and Lunar Reconnaissance Orbiter missions. 相似文献
5.
Phase-ratio imagery is a new tool of qualitative photometric analyses of the upper layer of the lunar regolith, which allows the identification of natural surface structure anomalies and artificially altered regolith. We apply phase-ratio imagery to analyze the Apollo-14, -15, and -17 landing sites. This reveals photometric anomalies of ∼170 × 120 m size that are characterized by lower values of the phase-function steepness, indicating a smoothing of the surface microstructure caused by the engine jets of the landing modules. Other photometric anomalies characterized by higher phase-function slopes are the result of regolith loosening by astronaut boots and the wheels of the Modular Equipment Transporter and the Lunar Roving Vehicle. We also provide a possible explanation for the high brightness of the wheel tracks seen in on-surface images acquired at very large phase angles. 相似文献
6.
We established an equation of state for nanocrystalline forsterite using multi-anvil press and diamond anvil cell. Comparative
high-pressure and high-temperature experiments have been performed up to 9.6 GPa and 1,300°C. We found that nanocrystalline
forsterite is more compressible than macro-powder forsterite. The bulk modulus of nanocrystalline forsterite is equal to 123.3
(±3.4) GPa whereas the bulk modulus of macro-powder forsterite is equal to 129.6 (±3.2) GPa. This difference is attributed
to a weakening of the elastic properties of grain boundary and triple junction and their significant contribution in nanocrystalline
sample compare to the bulk counterpart. The bulk modulus at zero pressure of forsterite grain boundary was determined to be
83.5 GPa. 相似文献
7.
Yuriy G. Shkuratov Vadim G. Kaydash Larissa V. Starukhina Serge D. Chevrel 《Planetary and Space Science》2005,53(12):1287-1301
We propose a technique that interpolates available lunar prospector gamma-ray spectrometer (GRS) data using Clementine UVVIS spectral reflectance images. The main idea is to use low resolution GRS data as a “ground truth” to establish relationships linking optical data and geochemical information maximizing the respective correlation coefficients. Then the relationships and Clementine UVVIS data are used to derive elemental abundance maps with significantly improved spatial resolution. The main limitation of the technique is its dependence on how well the abundance of the elements correlates with the Clementine UVVIS data. The technique can also be applied to analysis of coming D-CIXS/Smart-1 and AMIE/Smart-1 data to increase resolution of lunar compositional maps. As an illustration of the suggested technique, maps for the elements Fe, Ti, O, Al, Ca, and Mg with pixel size 15 km×15 km are presented. The Fe and Ti distributions resemble qualitatively to the maps obtained with the well-known technique by lucey et al. (2000a. Lunar iron and titanium abundance algorithms based on final processing of Clementine ultraviolet-visible images. J. Geophys. Res. 105, 20,297-20,306), though in our case the ranges of Fe and Ti variations are, respectively, wider and narrower than for lucey's maps. New maps for the elements Fe, Ti, O, Al, Ca, and Mg appear to be informative. For instance, the map of oxygen abundance demonstrates an anomaly in the crater Tycho. The maps of Fe and Al contents show for highland regions slight variations related to maturity degree. Reliability of this relation is confirmed with lunar sample data. The reason of the correlation between chemical composition and exposition age of the lunar surface can be the global transport of the lunar surface material due to meteorite impacts. 相似文献
8.
Vadym Aizinger Jennifer Proft Clint Dawson Dharhas Pothina Solomon Negusse 《Ocean Dynamics》2013,63(1):89-113
In this work, we present results of a numerical study of Corpus Christi Bay, Texas and surrounding regions and compare simulated model results to recorded data. The validation data for the year 2000 include the water elevation, velocity, and salinity at selected locations. The baroclinic computations were performed using the University of Texas Bays and Estuaries 3D (UTBEST3D) simulator based on a discontinuous Galerkin finite element method for unstructured prismatic meshes. We also detail some recent advances in the modeling capabilities of UTBEST3D, such as a novel turbulence scheme and the support for local vertical discretization on parts of the computational domain. All runs were conducted on parallel clusters; an evaluation of parallel performance of UTBEST3D is included. 相似文献
9.
Yu. G. Shkuratov M. A. Kreslavsky D. G. Stankevich V. G. Kaydash P. Pinet V. V. Shevchenko B. H. Foing J.-L. Josset 《Solar System Research》2003,37(4):251-259
We describe the future SMART-1 European Space Mission whose objective is to study the lunar surface from a polar lunar orbit. In particular, it is anticipated that selected regions of the Moon will be photographed using the AMIE camera with a mean spatial resolution of about 100 m in three spectral channels (0.75, 0.92, and 0.96 m) over a wide range of phase angles. Since these spectral channels and the AMIE resolution are close to those of the UVVIS camera onboard the Clementine spacecraft, the simultaneous processing of SMART-1 and Clementine data can be planned, for example, to obtain phase-ratio images. These images carry information on the structural features of the lunar surface. In particular, UVVIS/Clementine data revealed a photometric anomaly at the Apollo-15 landing site associated with the blowing of the lunar regolith by the lander engine. Anomalies were found in the ejection zones of several fresh craters. 相似文献
10.
In this paper, we continue our analysis of upwind‐mixed methods for advection–diffusion equations, which have been developed
and analyzed by the first author over the past several years. In previous work, our analysis has been limited to low order
approximating spaces, positive definite diffusion coefficients and Dirichlet boundary conditions. In this paper, we extend
our results to higher order approximating spaces, possibly zero diffusion, and more physically realistic boundary conditions.
Moreover, unlike previous papers, we avoid the use of Gronwall's Inequality, which can result in extremely large constants
in the stability and error bounds. Numerical results are presented for constant, linear and quadratic approximating spaces.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献