Removal of topographic effects from lunar images using Kaguya (LALT) and Earth-based observations     

Viktor V. Korokhin  Yuriy I. Velikodsky  Yuriy G. Shkuratov  Vadym G. Kaydash  Sergey Y. Gerasimenko  Nikolai V. Opanasenko  Gorden Videen  Carle Pieters 《Planetary and Space Science》2010,58(10):1298-1306

Lunar images acquired at non-zero phase angles show brightness variations caused by both albedo heterogeneities and local topographic slopes of the surface. To distinguish between these two factors, altimetry measurements or photoclinometry data can be used. The distinction is especially important for imagery of phase-function parameters of the Moon. The imagery is a new tool that can be used to study structural anomalies of the lunar surface. To illustrate the removal of the topographic effects from photometric images, we used Earth-based telescopic observations, altimetry measurements carried out with the Kaguya (JAXA) LALT instrument, and a new photoclinometry technique that includes analysis of several images of the same scenes acquired at different phase angles. Using this technique we have mapped the longitudinal component of lunar topography slopes (the component measured along the lines of constant latitude). We have found good correlations when comparing our map with the corresponding data from Kaguya altimetry. The removal of the topographic surface properties allows for the study of the phase-function parameters of the lunar surface, not only for flat mare regions, but for highlands as well.  相似文献   

The negative polarization parameters of the light scattered by the lunar surface: Mapping     

N. V. Opanasenko  A. N. Opanasenko  Yu. G. Shkuratov  V. G. Kaydash  Yu. I. Velikodsky  V. V. Korokhin 《Solar System Research》2009,43(3):210-214

The images of the southwestern part of the lunar disk showing the distributions of the negative polarization parameters of the light scattered by the lunar surface are presented. The distributions of the negative polarization minimum P _min, the inversion angle α_inv, and the polarization slope at the inversion point h significantly differ from the albedo image. This testifies to the fact that polarimetry yields independent information on the structure and optical properties of the lunar regolith.  相似文献   

Probable swirls detected as photometric anomalies in Oceanus Procellarum     

Yu. Shkuratov  V. Kaydash  N. Opanasenko  V. Korokhin  C. Pieters 《Icarus》2010,208(1):20-30

Images of the lunar nearside obtained by telescopes of Maidanak Observatory (Uzbekistan) and Simeiz Observatory (Crimea, Ukraine) equipped with Canon CMOS cameras and Sony CCD LineScan camera were used to study photometric properties of the lunar nearside in several spectral bands. A wide range of lunar phase angles was covered, and the method of phase ratios to assess the steepness of the phase function at different phase angles is applied. We found several areas with photometric anomalies in the south-west portion of the lunar disk that we refer to as Oceanus Procellarum anomalies. The areas being unique on the lunar nearside do not obey the inverse correlation between albedo and phase-curve slope, demonstrating high phase-curve slopes at intermediate albedo. Low-Sun images acquired with Lunar Orbiter IV and Apollo-16 cameras do not reveal anomalous topography of the regions, at least for scales larger than several tens of meters. The areas also do not have any thermal inertia, radar (70 and 3.8 cm), magnetic, or chemical/mineral peculiarities. On the other hand they exhibit a polarimetric signature that we interpret to be due to the presence of a porous regolith upper layer consisting of dust particles. The anomalies may be interpreted as regions of very fresh shallow regolith disturbances caused by impacts of meteoroid swarms consisting of rather small impactors. This origin is similar to one of the hypotheses for the origin of lunar swirls like the Reiner-γ formation. The photometric difference between the shallow and pervasive (Reiner-γ class) swirls is that the latter appear to have a significant amount of immature soils in the upper surface layers.  相似文献   

RCP 8.5��A scenario of comparatively high greenhouse gas emissions     

Keywan Riahi  Shilpa Rao  Volker Krey  Cheolhung Cho  Vadim Chirkov  Guenther Fischer  Georg Kindermann  Nebojsa Nakicenovic  Peter Rafaj 《Climatic change》2011,109(1-2):33-57

This paper summarizes the main characteristics of the RCP8.5 scenario. The RCP8.5 combines assumptions about high population and relatively slow income growth with modest rates of technological change and energy intensity improvements, leading in the long term to high energy demand and GHG emissions in absence of climate change policies. Compared to the total set of Representative Concentration Pathways (RCPs), RCP8.5 thus corresponds to the pathway with the highest greenhouse gas emissions. Using the IIASA Integrated Assessment Framework and the MESSAGE model for the development of the RCP8.5, we focus in this paper on two important extensions compared to earlier scenarios: 1) the development of spatially explicit air pollution projections, and 2) enhancements in the land-use and land-cover change projections. In addition, we explore scenario variants that use RCP8.5 as a baseline, and assume different degrees of greenhouse gas mitigation policies to reduce radiative forcing. Based on our modeling framework, we find it technically possible to limit forcing from RCP8.5 to lower levels comparable to the other RCPs (2.6 to 6 W/m²). Our scenario analysis further indicates that climate policy-induced changes of global energy supply and demand may lead to significant co-benefits for other policy priorities, such as local air pollution.  相似文献   

Textural evolution of perovskite in the Afrikanda alkaline–ultramafic complex,Kola Peninsula,Russia     

Naomi?J.?PotterEmail author  Matthew?R.?M.?Ferguson  Vadim?S.?Kamenetsky  Anton?R.?Chakhmouradian  Victor?V.?Sharygin  Jay?M.?Thompson  Karsten?Goemann 《Contributions to Mineralogy and Petrology》2018,173(12):100

Perovskite is a common accessory mineral in a variety of mafic and ultramafic rocks, but perovskite deposits are rare and studies of perovskite ore deposits are correspondingly scarce. Perovskite is a key rock-forming mineral and reaches exceptionally high concentrations in olivinites, diverse clinopyroxenites and silicocarbonatites in the Afrikanda alkaline–ultramafic complex (Kola Peninsula, NW Russia). Across these lithologies, we classify perovskite into three types (T1–T3) based on crystal morphology, inclusion abundance, composition, and zonation. Perovskite in olivinites and some clinopyroxenites is represented by fine-grained, equigranular, monomineralic clusters and networks (T1). In contrast, perovskite in other clinopyroxenites and some silicocarbonatites has fine- to coarse-grained interlocked (T2) and massive (T3) textures. Electron backscatter diffraction reveals that some T1 and T2 perovskite grains in the olivinites and clinopyroxenites are composed of multiple subgrains and may represent stages of crystal rotation, coalescence and amalgamation. We propose that in the olivinites and clinopyroxenites, these processes result in the transformation of clusters and networks of fine-grained perovskite crystals (T1) to mosaics of more coarse-grained (T2) and massive perovskite (T3). This interpretation suggests that sub-solidus processes can lead to the development of coarse-grained and massive perovskite. A combination of characteristic features identified in the Afrikanda perovskite (equigranular crystal mosaics, interlocked irregular-shaped grains, and massive zones) is observed in other oxide ore deposits, particularly in layered intrusions of chromitites and intrusion-hosted magnetite deposits and suggests that the same amalgamation processes may be responsible for some of the coarse-grained and massive textures observed in oxide deposits worldwide.  相似文献   

Rare earth element geochemistry of feldspars: examples from Fe-oxide Cu-Au systems in the Olympic Cu-Au Province,South Australia     

Kontonikas-Charos  Alkis  Ciobanu  Cristiana L.  Cook  Nigel J.  Ehrig  Kathy  Krneta  Sasha  Kamenetsky  Vadim S. 《Mineralogy and Petrology》2018,112(2):145-172

Mineralogy and Petrology - Rare earth element (REE) fractionation trends in feldspars are reported from Olympic Dam (including Wirrda Well and Phillip’s Ridge) and Cape Donington (Port...  相似文献   

Carbon isotope fractionation during experimental crystallisation of diamond from carbonate fluid at mantle conditions     

Vadim Reutsky  Yuri Borzdov  Yuri Palyanov  Alexander Sokol  Olga Izokh 《Contributions to Mineralogy and Petrology》2015,170(5-6):1-9

  相似文献   

Cases of a star's planar motion integrated in the gravitational field of a rotating system     

Vadim A. Antonov  Faziliddin T. Shamshiev 《Celestial Mechanics and Dynamical Astronomy》1994,59(3):209-219

The paper deals with some special cases of the existence of a local integral of motion in a two-dimensional potential field rotating with constant angular velocity. In this case the trajectories may be completely determined, which is not always possible in other cases with a local integral, in contrast to the cases with a true integral. Some cases where the trajectories can be determined analytically are trivial but there are also some new nontrivial cases.  相似文献   

New Earth-based absolute photometry of the Moon     

Yu.I. Velikodsky  N.V. Opanasenko  V.V. Korokhin  V.G. Kaydash  Sh.A. Ehgamberdiev 《Icarus》2011,214(1):30-45

A 2-month series of quasi-simultaneous imaging photometric observations of the Moon and the Sun has been performed at Maidanak Observatory (Uzbekistan). New absolute values of lunar albedo have been obtained. Maps of lunar apparent albedo and equigonal albedo at phase angles 1.7-73° at wavelength 603 nm are presented. The standard deviation of our data from a best-fitted phase curve is 2%. The average ratio of the Clementine albedo to ours is 1.41. While the ratio of ROLO albedo to ours is 0.87, our data are in agreement with independent measurements of absolute albedo by Saiki et al. (Saiki, K., Saito, K., Okuno, H., Suzuki, A., Yamanoi, Y., Hirata N., Nakamura, R. [2008]. Earth Planets Space 60, 417-424) at a phase angle near 7°. A phase ratio imaging near opposition (1.6°/2.7°) shows almost the same ratio for maria and highlands, though bright craters (e.g., Tycho, Copernicus, Aristarchus) clearly reveal smaller slopes of phase function. This is an unexpected result, as the craters are bright and one could anticipate a manifestation of the coherent backscattering effect resulting in the opposition spike increasing at so small phase angles.  相似文献   

Structural disturbances of the lunar surface caused by spacecraft     

V. G. Kaydash  Yu. G. Shkuratov 《Solar System Research》2012,46(2):108-118

From the lunar surface survey performed with a narrow-angle camera of the Lunar Reconnaissance Orbiter (LRO) spacecraft, the distributions of the phase ratios of the Apollo 11 and 12 landing sites and the Ranger 9 impact site were mapped. In the acquired images, the traces of the structural disturbances of the lunar regolith layer caused by the jet flows are seen. In the Ranger 9 impact site, one can see the crater of about 15 m across with a ray system, which is hardly noticeable in the brightness picture, but has a high contract in the phase ratio picture. The character of the photometric anomaly of the rays of this crater shows that they are formed by the ejected stones composing the rugged relief, which induces a strong shadow effect. At the same time, the influence of jet flows from the rocket engines smooths the relief and leads to the photometric anomaly of the opposite sign. The estimate of the maturity degree of the lunar regolith in the Apollo 11 and 12 landing sites obtained from the SELENE spectral survey suggests that the depth of the influence of the rocket engines on the soil is small, and the surface of the impact crater formed by the Ranger 9 spacecraft contains a large amount of the immature soil.  相似文献