Optical studies of the X-ray transient XTE J2123−058 – I. Photometry

We present optical photometry of the X-ray transient XTE J2123−058, obtained in 1998 July–October. The light curves are strongly modulated on the 5.95-h orbital period, and exhibit dramatic changes in amplitude and form during the decline. We used synthetic models, which include the effect of partial eclipses and X-ray heating effects, to estimate the system parameters, and we constrain the binary inclination to be i =73°±4. The model is successful in reproducing the light curves at different stages of the decay by requiring the accretion disc to become smaller and thinner by 30 per cent as the system fades by 1.7 mag in the optical. From August 26 the system reaches quiescence with a mean magnitude of R =21.7±0.1 and our data are consistent with the optical variability being dominated by the ellipsoidal modulation of the companion.     

WRF ARW and CHIMERE models for numerical forecasting of surface ozone concentration

Results of joint calculations with meteorological WRF ARW model and chemistry transport CHIMERE model are considered as a basis of the modern system of the air quality assessment and forecasting. The system was designed in the Russian Hydrometeorological Center and Institute of Applied Physics of the Russian Academy of Sciences. Detailed prognostic information about the atmosphere state provided by the WRF ARW was used in the CHIMERE model for describing the air mass transport processes, chemical transformation, and pollution deposition. Results of retrieval and forecast of surface ozone concentration as one of main air quality indicators are under consideration. Calculations of ozone concentrations for different configurations of a prognostic system differ in resolution of model grid and in the way the boundary conditions are prescribed.     

Chemical composition and species attribution of tourmalines from a rare-metal pegmatite vein with scapolite, Sangilen Upland, Tuva

A detailed study of the chemical composition and substitutions in calcium tourmalines from a scapolite-bearing rare-metal pegmatite vein from the Sol’bel’der River basin has shown that their species attribution is determined by occupancy of octahedral site Y. The composition of the yellow tourmaline most abundant in the central part of the pegmatite bodyis rather constant and characterized by the ideal formula Ca(Mg₂Li)Al₆(Si₆O₁₈)(BO₃)₃(OH)₃F. Variations in the chemical composition of zonal tourmaline crystals from the contact part of the pegmatite are controlled by abrupt change in the chemical medium during their formation. The yellow cores of these crystals are close in composition to tourmaline from the central part of the pegmatite vein. The Mg content abruptly decreases toward the crystal margin: Mg²⁺ → Fe²⁺, 2Mg²⁺ → Li⁺ + Al³⁺, and Mg²⁺ + OH → Al³⁺ + O²⁻. The composition of dark green marginal zones in tourmaline is characterized by the ideal formula Ca(Al_1.5Li_1.5)Al₆(Si₆O₁₈)(BO₃)₃ (OH₂O)(F). The results indicate specific formation conditions of pegmatite. The crystallochemical formulas of the studied tourmalines allow us to regard them as new mineral species in the tourmaline group.     

Moscow Urban Heat Island: Detection,boundaries, and variability

The determination of the anthropogenic impact on the thermal regime of a megalopolis is discussed. The nominal boundaries of the megalopolis thermal effects are determined taking into account orographic and landscape effects and the variability of temperature difference between the center of the city and its suburbs. It is proposed to use the data of stations located within 40-50 km from the urban agglomeration boundaries for calculating the anthropogenic component of the urban heat island. The parameters of the heat island in Moscow are determined from the measurement data on maximum and minimum daily surface air temperature in 2012-2016, and their significant seasonal and intradaily variability is revealed. It is corroborated that anthropogenic causes for the higher air temperature in Moscow as compared with suburbs during the cold season are the release and loss of heat of heating systems; in the absence of snow cover the anthropogenic effect of these sources is enhanced by the thermal radiation of the urban surface.     

Gas Distribution Features in the Upper Layer of Marine Sediments in the Continental Shelf of the Laptev Sea–Arctic Ocean Profile

Oceanology - Hydrocarbon gases (CH4, C2H4, C2H6, C3H6, C3H8, C4H8, n-C4H10, iC4H10, nC5H12, iC5H12, neo-C5H12), CO2, H2S, CH3SCH3, and COS were obtained from various marine sediment horizons at a...     

Electron concentration variations in the F1-region during magnetic storms in a low solar activity period

Vertical sensing data obtained with the help of DPS-4 digisondes in Irkutsk and Yakutsk are used to analyze the response of the F1-layer to magnetic disturbances in May 2005. It is found that the electron concentration is decreased at heights of 150–200 km during magnetic storms, and the amplitude of this negative disturbance increases with height. This effect is more distinct in Yakutsk than Irkutsk. The main gas constituents of the thermosphere during disturbed periods are estimated.     

Ozone anomalies in spring over Russia

During more than half-century ozone observations in the high latitudes of the Northern Hemisphere, the significant anomalies of total ozone (TO) with the duration of a month and more were observed in March 1995, 1996, 1997, and 2011 (in 1997 and 2011, they were the most significant and the longest). The maximum total ozone deficit zone over the land was observed over the northern coast of East Siberia. The ozone loss in the anomalies in 1997 and 2011 were associated with the unusual behavior of the circumpolar vortex which was unusually deep, stable, and durable in these years that resulted in the abnormal low temperature in the stratosphere in the high latitudes of the Northern Hemisphere. In subpolar latitudes, the temperature in the lower stratosphere during the period from December 2010 to February 2011 was lower than in 1997. In 2011 due to the durable springtime anomaly, almost over the whole territory of Russia the average annual ozone values turned out to be significantly lower than in the previous decade. The total ozone deficit in the circumpolar vortex in spring 1997 and 2011 amounted to about 140 DU. The formation of large TO anomaly in 2011 indicates that the long-term evolution of ozone layer conditions is a part of the long-term evolution of the Earth climate system.     

Ozone content over the Russian federation in the second quarter of 2013

The review is compiled on the basis of the results of the operation of the total ozone (TO) monitoring in the CIS and Baltic countries functioning in the operational regime at the Central Aerological Observatory (CAO). The monitoring system uses the data from the national network with M-124 filter ozonometers under methodological supervision of the Main Geophysical Observatory. The quality of the functioning of the entire system is under operational control based on the observations obtained from the OMI satellite equipment (NASA, the United States). The basic TO observation data are generalized for each month of the second quarter of 2013 and for the quarter as a whole. The results of regular observations of surface ozone content carried out in other organizations in Russia are also considered.     

Ozone content over the Russian Federation in the second quarter of 2014

The review is compiled on the basis of the results of the total ozone (TO) monitoring in the CIS and Baltic countries that functions in the operational regime at the Central Aerological Observatory (CAO). The monitoring system uses the data from the national network equipped with M-124 filter ozonometers under the methodological supervision of the Main Geophysical Observatory. The quality of the functioning of the entire system is under operational control based on the observations obtained from the OMI satellite equipment (NASA, the United States). The basic TO observational data are generalized for each month of the second quarter of 2014 and for the quarter as a whole. The results are also given of the regular observations of surface ozone content carried out in the Moscow region and characterizing ozone conditions in the surface layer in the center of the European part of Russia.