Thermodynamic Evaluation of Mineral Balance in Water Thickness of the Soda Lake Doroninskoe(Eastern Transbaikalia,Russia)     

Svetlana V. BORZENKO  Leonid V. ZAMANA  Daria S. SUVOROVA 《《地质学报》英文版》2014,88(Z1):123-124

正In recent years,lakes,including salted,attract the attention of researchers,also when reconstructing last climate changes using the bottom sediments(Solotchina et al.,2008,et al.).In this case the different geochemical  相似文献   

Vulnerability of Bulgarian agriculture to drought and climate variability with focus on rainfed maize systems     

Z.?Popova  M.?Ivanova  D.?Martins  L.?S.?PereiraEmail author  K.?Doneva  V.?Alexandrov  M.?Kercheva 《Natural Hazards》2014,74(2):865-886

Bulgarian agriculture is affected by droughts and, likely, by climate change. Thus, aiming at assessing its vulnerability, this study includes a general characterization of climate variability in eight selected locations, both in northern and southern Bulgaria. Trend tests were applied to monthly precipitation, maximum and minimum temperature and to the Standardized Precipitation Index with two-month time step (SPI-2) relative to the period of 1951–2004. Negative trends were identified for precipitation and SPI-2 at various locations, mainly in the Thrace Plain, indicating that dryness is likely to be increasing in Bulgaria. The vulnerability of rainfed maize systems to drought was studied using the previously calibrated WinISAREG model and the Stewart’s yield model to compute both the relative yield decrease (RYD) due to water stress and the corresponding net irrigation required to overcome those losses. Results identified a strong relation between SPI-2 for July–August (SPI-2_July–Aug) and RYD. Results also show that yield losses are higher when the soils have a smaller soil water holding capacity. For the various regions under study, thresholds for RYD were defined considering the related economic impacts and the influence of soil characteristics on the vulnerability of the rainfed maize systems. Finally, to support drought risk management, SPI-2_July–Aug thresholds were developed to be used as indicators of the economic risk of rainfed maize for various climate regions and soil groups in Bulgaria.  相似文献   

Seasonal Dynamics of Algal Flora in the Stratified Kislo-Sladkoe Lake Partially Separated from the White Sea     

Ivanova  D. A.  Krasnova  E. D.  Voronov  D. A.  Radchenko  I. G. 《Oceanology》2022,62(2):207-220

Oceanology - The article presents data on the composition and abundance of algal flora in the coastal stratified Kislo-Sladkoe Lake (the Karelian coast of the White Sea) after its flushing with...  相似文献   

Ozone content over the Russian Federation in the third quarter of 2013     

A. M. Zvyagintsev  N. S. Ivanova  G. M. Kruchenitskii  I. N. Kuznetsova 《Russian Meteorology and Hydrology》2013,38(11):792-795

The review is compiled on the basis of the results of monitoring the total ozone (TO) 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 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 first quarter of 2013 and for the quarter as a whole. The data on the development of the Antarctic spring ozone anomaly in August and September 2013 are presented as well as the results of regular observations of the surface ozone content carried out in Moscow region by GPBU Mosekomonitoring and CAO.  相似文献   

Experimental simulation of oxygen isotopic exchange in olivine and implication for the formation of metamorphosed carbonaceous chondrites     

Marina A. Ivanova  Cyril A. Lorenz  Ian A. Franchi  Andrei Y. Bychkov  Jeffrey E. Post 《Meteoritics & planetary science》2013,48(10):2059-2070

We have conducted hydration–dehydration experiments on terrestrial olivine to investigate the behavior of oxygen isotopic fractionation to test the hypothesis that multiple cycles of aqueous and thermal processing on a parent asteroid comprise a genetic relationship between CM2s and metamorphosed carbonaceous chondrites (MCCs). Two experiments were undertaken. In the first experiment, serpentine was obtained by hydrating terrestrial olivine (Fo_90.9) in the laboratory. During this experiment, olivine was reacted with isotopically heavy water (δ¹⁸O 21.5‰) at T = 300 °C,  = 300 bar, for 100 days. The oxygen isotopic composition of the experimental serpentine was enriched in ¹⁸O (by 10 ‰ in δ¹⁸O) due to exchange of oxygen isotopes between olivine and the ¹⁸O‐rich water. Dehydrated serpentine was then produced during laboratory heating experiment in vacuum, at T = 930 °C, for 1 h. The oxygen isotopic composition of the dehydrated serpentine was enriched in ¹⁸O by a further 7 ‰. The net result of the hydration–dehydration process was an enrichment of ¹⁸O in the final material by approximately 17‰. The new experimental results suggest that the oxygen isotopic compositions of MCCs of the Belgica‐like group, including Dhofar 225 and Dhofar 725, could be derived from those of typical CM2 chondrites via several cycles of hydration–dehydration caused by aqueous alteration and subsequent thermal metamorphism within their parent asteroids.  相似文献   

Observations of the long-lasting activity of the distant Comets 29P Schwassmann-Wachmann 1, C/2003 WT42 (LINEAR) and C/2002 VQ94 (LINEAR)     

Oleksandra V. Ivanova  Yury V. Skorov  Pavlo P. Korsun  Jürgen Blum 《Icarus》2011,211(1):559-567

We investigated three comets, which are active at large heliocentric distances, using observations obtained at the 6-m BTA telescope (SAO RAS, Russia) in the photometric mode of the focal reducer SCORPIO. The three comets, 29P/Schwassmann-Wachmann 1, C/2003 WT42 (LINEAR), and C/2002 VQ94 (LINEAR), were observed after their perihelion passages at heliocentric distances between 5.5 and 7.08 AU. The dust production rates in terms of Afρ was measured for these comets. Using the retrieved values, an average dust production rate was derived under different model assumptions. A tentative calculation of the total mass loss of the comet nucleus within a certain observation period was executed. We calculated the corresponding thickness of the depleted uppermost layer where high-volatile ices completely sublimated. The results obtained in our study strongly support the idea that the observed activity of Comet SW1 requires a permanent demolition of the upper surface layers.  相似文献   

REMOTE SENSING AND THE MONITORING OF URBAN-OASES ECOSYSTEMS     

N. V. Ivanov  E. B. Ivanova  M. K. Kuzybayev  S. N. Nazarova 《地理信息系统科学与遥感》2013,50(1)

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Experimental study of the self-organization process of a fluidized granite melt under decompression     

F. A. Letnikov  L. A. Ivanova  V. Ya. Medvedev  K. E. Kuznetsov 《Doklady Earth Sciences》2012,443(2):506-508

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Epochs of the formation of amber and its distribution in nature     

A. V. Ivanova  S. A. Machulina  L. B. Zaitseva 《Lithology and Mineral Resources》2012,47(1):18-22

Distribution and genesis of amber-type resins are discussed. The kerogen evolution diagram (atomic ratios of three key elements: carbon, hydrogen, and oxygen) has been used for comparing differentage fossil resins and refining their genesis and the results of postdiagenetic effects on them. Paleozoic and Meso-Cenozoic fossil resins occupy different areas in the mentioned diagram, suggesting a higher transformation degree of resins from the Paleozoic sediments and different types of resin-producing vegetation in the Paleozoic and Meso-Cenozoic. Distribution of data points on the plot can provide insight into postdiagenetic processes (magmatism, weathering) responsible for the transformation of some fossil resins. Epochs of intense succinosis and large-scale amber appearance are attributed to global events that impaired stable conditions for the growth of resin-generating forest vegetation.  相似文献   

Erosion-accumulative activity of the bottom currents on the continental rise of Brazil     

D. G. Borisov  I. O. Murdmaa  E. V. Ivanova  A. G. Roslyakov  R. A. Anan’ev 《Doklady Earth Sciences》2013,452(1):979-982

Several high-resolution “SES 2000 deep” seismic profiles and a core of bottom sediments were obtained in cruises 33, 35, and 37 of the R/V Akademik Ioffe in the area of the Columbia channel (continental rise of Brazil, South America). The analysis of seismic facies and direct correlation of acoustic and lithological data indicates that sedimentation in this area is mostly controlled by the contour current of the Antarctic Bottom Water (AABW). The gravity flows from seamounts and continental slope only episodically contributed coarser material to the deposition of the muddy contourites. The mixed gravitite-contourite systems consisting of accumulative bodies (drifts) and erosion channels are the results of interaction of these sedimentation processes.  相似文献