Distribution of the spectropolarimetric parameter of the moon in the northern part of Ocean Procellarum for a large phase angle

Polarimetric observations of the moon have been carried out at λ_eff = 0.48 and 0.63 μm using the 50 cm telescope of the Maidanak (Middle Asia) observatory. Imaging has been performed using a Canon-350D camera with a CMOS array and rotating polaroid. The investigation covered the north-western part of the lunar disk comprising the northern part of Ocean Procellarum and obtained the images representing the albedo, polarization degree, color index, and polarimetric color ratio at a phase angle of 96°. It is the first time that the latter parameter has been imaged with a resolution of approximately 1 km. Its pattern has proved to resemble that of the color index, although some important differences can be seen. This shows that spectropolarimetric observations of the moon can give new information on the composition and optical properties of the lunar regolith.     

Distribution and interplay of geologic processes on Titan from Cassini radar data

The Cassini Titan Radar Mapper is providing an unprecedented view of Titan’s surface geology. Here we use Synthetic Aperture Radar (SAR) image swaths (Ta-T30) obtained from October 2004 to December 2007 to infer the geologic processes that have shaped Titan’s surface. These SAR swaths cover about 20% of the surface, at a spatial resolution ranging from ∼350 m to ∼2 km. The SAR data are distributed over a wide latitudinal and longitudinal range, enabling some conclusions to be drawn about the global distribution of processes. They reveal a geologically complex surface that has been modified by all the major geologic processes seen on Earth - volcanism, tectonism, impact cratering, and erosion and deposition by fluvial and aeolian activity. In this paper, we map geomorphological units from SAR data and analyze their areal distribution and relative ages of modification in order to infer the geologic evolution of Titan’s surface. We find that dunes and hummocky and mountainous terrains are more widespread than lakes, putative cryovolcanic features, mottled plains, and craters and crateriform structures that may be due to impact. Undifferentiated plains are the largest areal unit; their origin is uncertain. In terms of latitudinal distribution, dunes and hummocky and mountainous terrains are located mostly at low latitudes (less than 30°), with no dunes being present above 60°. Channels formed by fluvial activity are present at all latitudes, but lakes are at high latitudes only. Crateriform structures that may have been formed by impact appear to be uniformly distributed with latitude, but the well-preserved impact craters are all located at low latitudes, possibly indicating that more resurfacing has occurred at higher latitudes. Cryovolcanic features are not ubiquitous, and are mostly located between 30° and 60° north. We examine temporal relationships between units wherever possible, and conclude that aeolian and fluvial/pluvial/lacustrine processes are the most recent, while tectonic processes that led to the formation of mountains and Xanadu are likely the most ancient.     

Dependence of normal albedo of lunar regions on wavelength

Normal albedos of thirteen lunar regions are determined at five wavelengths between 4000 and 8000 Å. The deduced values agree with those of the previous investigators except those given by Gehrelset al. (1964) and Van Diggelen (1965). They increase monotonically with the wavelength. At the shortest wavelength, a slight enhancement is detected for most of the regions observed.     

Variations in climatic and hydrological parameters in the Selenga River basin in the Russian Federation

The variations in average annual surface air temperature, precipitation, and runoff in the Selenga River basin (within Russia) are analyzed. It is demonstrated that the considerable increase in average annual temperature of surface air layers occurred in the 1980s-1990s. The decrease in peak water discharge in the rivers and the increase in the frequency of low-water periods were revealed in the forest-steppe and steppe zones of the Selenga River basin in 2001-2010. In the southwestern mountain regions (the Dzhida River basin) the river runoff increased during that period.     

Mineral Composition of Manganese Crusts from Belyaevskii Volcano (Sea of Japan)

Doklady Earth Sciences - The polygenic mineral composition of Mn crusts from Belyaevskii Volcano of the Central Basin of the Sea of Japan is determined. The crusts are found for the first time to...     

The structure of the mid- and high-latitude ionosphere during the November 2004 storm event obtained from GPS observations

GPS data from the International GNSS Service (IGS) network were used to study the development of the severe geomagnetic storm of November 7–12, 2004, in the total electron content (TEC) on a global scale. The TEC maps were produced for analyzing the storm. For producing the maps over European and North American sectors, GPS measurements from more than 100 stations were used. The dense network of GPS stations provided TEC measurements with a high temporal and spatial resolution. To present the temporal and spatial variation of TEC during the storm, differential TEC maps relative to a quiet day (November 6, 2004) were created. The features of geomagnetic storm attributed to the complex development of ionospheric storm depend on latitude, longitude and local time. The positive, as well as negative effects were detected in TEC variations as a consequence of the evolution of the geomagnetic storm. The maximal effect was registered in the subauroral/auroral ionosphere during substorm activity in the evening and night period. The latitudinal profiles obtained from TEC maps for Europe gave rise to the storm-time dynamic of the ionospheric trough, which was detected on November 7 and 9 at latitudes below 50°N. In the report, features of the response of TEC to the storm for European and North American sectors are analyzed.     

Maximum extent of the Eurasian ice sheets in the Barents and Kara Sea region during the Weichselian

Based on field investigations in northern Russia and interpretation of offshore seismic data, we have made a preliminary reconstruction of the maximum ice-sheet extent in the Barents and Kara Sea region during the Early/Middle Weichselian and the Late Weichselian. Our investigations indicate that the Barents and Kara ice sheets attained their maximum Weichselian positions in northern Russia prior to 50 000 yr BP, whereas the northeastern flank of the Scandinavian Ice Sheet advanced to a maximum position shortly after 17 000 calendar years ago. During the Late Weichselian (25 000-10 000 yr BP), much of the Russian Arctic remained ice-free. According to our reconstruction, the extent of the ice sheets in the Barents and Kara Sea region during the Late Weichselian glacial maximum was less than half that of the maximum model which, up to now, has been widely used as a boundary condition for testing and refining General Circulation Models (GCMs). Preliminary numerical-modelling experiments predict Late Weichselian ice sheets which are larger than the ice extent implied for the Kara Sea region from dated geological evidence, suggesting very low precipitation.     

Modeling rhamnolipids production by Pseudomonas aeruginosa from immiscible carbon source in a batch system

A mathematical model to predict the rhamnolipids production by Pseudomonas aeruginosa from oleic acid in a two phase liquid-liquid batch reaction system, was developed in this study. The model was based on two theoretical assumptions: 1) the convective oleic acid mass transfer is coupled to a bioreaction in the aqueous liquid bulk, and 2) the volume of the immiscible oleic acid drops and the saturation concentration at the interface are a function of rhamnolipids production. The model was able to accurately predict the experimental growth of the Pseudomonas aeruginosa strain, and the rhamnolipids production data with oleic acid as carbon source. This mathematical approach indicated a high correspondence between the saturation dimensionless profiles of oleic acid at the interface and the experimental profiles of surface tension difference. This modeling approach may constitute a useful tool in the design and scaling-up of bioreactors applied to the production of biosurfactants with immiscible carbon sources.     

Effects of a mudcake on Stoneley waves in a fluid-filled porous formation around a borehole

A mudcake formed on the borehole wall between a fluid-filled porous formation and the borehole fluid can affect Stoneley wave propagation used to estimate the formation permeability. The mudcake effect on the permeability dependence of radial oscillations of borehole fluid is investigated in a system with a source generating radial acoustic waves in the borehole and hydrophones (pressure sensors) that record the respective attenuating oscillations of the borehole fluid. The permeability of the porous formation is estimated from theoretical permeability dependence of the attenuation exponent, knowing the time dependence of the exponential attenuation of borehole fluid oscillations.     

Investigation of the evolution of coronal bright points and magnetic field topology

Our investigation has been carried using the instruments onboard the Solar Dynamics Observatory (SDO) providing a high resolution of images (AIA photographs and HMI magnetograms). We have investigated the structure and magnetic evolution of several coronal bright points and small scale N-S polarity magnetic fluxes closely associated with them. We also compare the evolution of the magnetic polarities of elementary isolated sources of positive and negative fluxes (magnetic bipoles) and coronal bright points. Tiny (“elementary”) coronal bright points have been detected. A standard coronal bright point is shown to be a group of “elementary” coronal bright points that flare up sequentially. Our investigation shows that a change in the magnetic fluxes of opposite polarities is observed before the flare of a coronal bright point. We show that not all cases of the formation of coronal bright points are described by the magnetic reconnection model. This result has not been considered previously and has not been pointed out by other authors.