Vertical structure of the Venus cloud top from the VeRa and VIRTIS observations onboard Venus Express     

Y.J. Lee  D.V. Titov  S. Tellmann  A. Piccialli  N. Ignatiev  M. Pätzold  B. Häusler  G. Piccioni  P. Drossart 《Icarus》2012,217(2):599-609

We investigate the Venus cloud top structure by joint analysis of the data from Visual and Thermal Infrared Imaging Spectrometer (VIRTIS) and the atmospheric temperature sounding by the Radio Science experiment (VeRa) onboard Venus Express. The cloud top altitude and aerosol scale height are derived by fitting VIRTIS spectra at 4–5 μm with temperature profiles taken from the VeRa radio occultation. Our study shows gradual descent of the cloud top from 67.2 ± 1.9 km in low latitudes to 62.8 ± 4.1 km at the pole and decrease of the aerosol scale height from 3.8 ± 1.6 km to 1.7 ± 2.4 km. These changes correlate with the mesospheric temperature field. In the cold collar and high latitudes the cloud top position remarkably coincides with the sharp minima in temperature inversions suggesting importance of radiative cooling in their maintenance. This behaviour is consistent with the earlier observations. Spectral trend of the cloud top altitude derived from a comparison with the earlier observations in 1.6–27 μm wavelength range is qualitatively consistent with sulphuric acid composition of the upper cloud and suggests that particle size increases from equator to pole.  相似文献   

Studies of the planetary atmospheres in Russia (2007–2010)     

O. I. Korablev  L. V. Zasova  A. A. Fedorova  D. V. Titov  N. I. Ignatiev  A. V. Rodin  V. I. Shematovich  D. A. Belyaev  I. V. Khatuntsev  M. N. Izakov  A. V. Shakun  A. V. Burlakov  B. S. Mayorov 《Izvestiya Atmospheric and Oceanic Physics》2012,48(3):309-331

An overview of results obtained in the field of planetary atmosphere studies in Russia in 2007?C2010 prepared by the Commission on Planetary Atmospheres of the National Geophysical Committee for the National Report on Meteorology and Atmospheric Sciences to the XXV General Assembly of the International Union of Geodesy and Geophysics (Melbourne, 28 June?C7 July 2011) [1, 2] is presented.  相似文献   

The Local Group dwarf Leo T: H i on the brink of star formation     

Emma V. Ryan-Weber  Ayesha Begum  Tom Oosterloo  Sabyasachi Pal  Michael J. Irwin  Vasily Belokurov  N. Wyn Evans  Daniel B. Zucker 《Monthly notices of the Royal Astronomical Society》2008,384(2):535-540

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Real-Time Assessment of the 16 September 2015 Chile Tsunami and Implications for Near-Field Forecast     

Liujuan Tang  Vasily V. Titov  Christopher Moore  Yong Wei 《Pure and Applied Geophysics》2016,173(2):369-387

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Source Models and Near-Field Impact of the 1 April 2007 Solomon Islands Tsunami     

Yong Wei  Hermann M. Fritz  Vasily V. Titov  Burak Uslu  Chris Chamberlin  Nikos Kalligeris 《Pure and Applied Geophysics》2015,172(3-4):657-682

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Tsunami Simulation Using Sources Inferred from Various Measurement Data: Implications for the Model Forecast     

Edison Gica  Vasily V. Titov  Christopher Moore  Yong Wei 《Pure and Applied Geophysics》2015,172(3-4):773-789

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Estimation of multi-scale temporal variability of air and water temperature in the northeastern part of the Black Sea     

V. B. Titov 《Russian Meteorology and Hydrology》2009,34(5):316-320

Standard deviations of mesoscale, synoptic, seasonal, and interannual fluctuations of the air and water temperature are calculated from long-term measurements. The contributions of each type of fluctuation to the total temporal variability are estimated. The intraannual cycle of variability of monthly (long-term) means of mesoscale and synoptic fluctuations is considered.  相似文献   

Parameters of the lower layer of saltation over desert territories     

G. I. Gorchakov  A. A. Titov  D. V. Buntov 《Doklady Earth Sciences》2009,424(1):90-94

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Uranium Behavior in the Process of Primary Pitchblende Ores Alteration by the Post‐ore Hydrothermal Solutions: An Application to Assessment of Uranium Migration from Underground Spent Nuclear Fuel Repositories     

Nikolay P. Laverov  Vasily I. Velichkin  Ai Fujiwara  Naotatsu Shikazono  Alexey P. Aleshin  Enver E. Asadulin  Vyacheslav N. Golubev  Tatiana L. Krylova  Alexander A. Pek  Igor V. Chernyshev 《Resource Geology》2009,59(4):342-358

It has been shown that the main uranium ore mineral, pitchblende (uranium dioxide), is a natural analog of synthetic uraninite (also uranium dioxide), which constitutes 96% of spent nuclear fuel (SNF). Geochronological studies of the U‐Pb isotope systems in unaltered pitchblende from the orebodies reveal that these systems remained completely closed over the entire period (approximately 135 Ma) since the formation of the deposits. The bulk of the primary uranium ores within the Streltsovskoye ore field was influenced to various degrees by post‐ore hydrothermal solutions that led to pitchblende spherulites being replaced by pseudomorphs of an amorphous phase with a U‐Si composition; this phase also re‐precipitated in veinlets proximal to the pitchblende pseudomorphs. A technique specially developed by the authors was used to carry out quantitative counts of the abundance of uranium minerals by calculating the uranium mass balance in one of the orebodies subjected to hydrothermal alteration. The calculations reveal minimal uranium loss from the orebody. Uranium liberated in the process of the pseudomorphic replacement of pitchblende was immediately fixed, in situ, in the newly formed coffinite‐like amorphous U‐Si phase as a result of the development of an efficient geochemical barrier that prevented the long‐distance migration of uranium. In assessing the long‐term safety of underground SNF repositories, the results of the present study give us confidence that SNF uraninite, in terms of the preservation of its integrity as a mineral phase, provides for the reliable long‐term isolation of uranium, transuranium elements, and fission products that are “sealed” in the uraninite matrix. In the case of the mineral transformation of the uraninite matrix by hydrothermal solutions, the liberated uranium would be efficiently immobilized by the newly formed amorphous U‐Si phase.  相似文献   

Baiyun Cave in Naigu Shilin,Yunnan Karst,China   总被引：1，自引：3，他引：1  

S.EBELA  T.SLABE  J.KOGOVEK  P.PRUNER 《《地质学报》英文版》2001,75(3):279-287

The Baiyun cave is a 380 m long karst cave in the Naigu Shilin, situated 70 km southeast of Kunming, Yunnan Province, China. The prevailing orientations of the cave passages are N110°-120°E and N0°-10°W and those of the fissures in the cave are N30°-40°W and N20°-30°W. The cave is developed in the thick-bedded Lower Permian Qixia Formation. The cave has an active water flow and is currently at the near water-table stage. There are large amounts of different infills of cave sediments. The cave shows different stages of paragenesis. The palaeomagnetic analysis of cave sediments shows that their ages are younger than 780 ka B.P. (the Brunhes Chron). The upper part of the sampled profile belongs to the reverse Blake event (112.3-117.9 ka B.P.). The formation of the Baiyun cave is directly connected with the development of the Naigu Shilin. The formation of karst underground and surface features depends on the regional tectonic deformation and the Cenozoic extension of the study area.  相似文献