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Sanja Mrki?Ksenija Stojanovi? Aleksandar Kosti?Hans Peter Nytoft Aleksandra Šajnovi? 《Organic Geochemistry》2011,42(6):655-677
The origin, depositional environment and maturity of petroleum source rocks were determined via conventional whole rock and biomarker analysis of samples from wells in the Banat Depression, where the most important Serbian oil and gas fields are located. The organic matter (OM) in organic-rich upper Tertiary siltstones and marls consists predominantly of Type II kerogen. Numerous biomarker parameters indicated mixed algal-terrestrial OM, related to a brackish or freshwater environment, whose salinity decreased from Middle to Upper Miocene. The OM was deposited under variable redox conditions, reducing to sub-oxic.The wells in the Banat Depression experienced variable high rates of rapid heating, providing an opportunity for examining the applicability of different thermal indicators in a hyperthermal basin. Rock-Eval and numerous biomarker parameters indicate that the main stage of oil generation begins at ca.130 °C and vitrinite reflectance (Rc) ca. 0.63% and reaches a maximum at ca.145-150 °C and Rc ca. 0.72-0.75%, while the late stage of oil generation starts at ca.155 °C and ca. Rc 0.78%, which corresponds, depending on geothermal gradient, to relative depths of 2100-2300 m, 2600-2900 m and 3050-3100 m, respectively. The naphthalene and phenanthrene maturity parameters proved to be less applicable than the biomarker ratios, particularly in the early to moderate maturation range. The newly proposed parameter C(14a)-homo-26-nor-17α(H)-hopane/C30hopane (C30HH/C30H) proved applicable to a wide range of maturity. 相似文献
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Dušan Jovanović Miro Govedarica Filip Sabo Dubravka Sladić Aleksandar Ristić 《国际地球制图》2015,30(5):483-505
Main objective of this study was to establish a relationship between land cover and land surface temperature (LST) in urban and rural areas. The research was conducted using Landsat, WorldView-2 (WV-2) and Digital Mapping Camera. Normalised difference vegetation index and normalised difference built-up index were used for establishing the relation between built-up area, vegetation cover and LST for spatial resolution of 30 m. Impervious surface and vegetation area generated from Digital Mapping Camera from Intergraph and WV-2 were used to establish the relation between built-up area, vegetation cover and LST for spatial resolutions of 0.1, 0.5 and 30 m. Linear regression models were used to determine the relationship between LST and indicators. Main contribution of this research is to establish the use of combining remote sensing sensors with different spectral and spatial resolution for two typical settlements in Vojvodina. Correlation coefficients between LST and LST indicators ranged from 0.602 to 0.768. 相似文献
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Behzad Jamali Ehsan Haghighat Aleksandar Ignjatovic João P. Leitão Ana Deletic 《水文研究》2021,35(4):e14064
Two-dimensional hydrodynamic models numerically solve full Shallow Water Equations (SWEs). Despite their high accuracy, these models have long simulation run times and therefore are of limited use for exploratory or real-time flood predictions. We investigated the possibility of improving flood modelling speed using Machine Learning (ML). We propose a new method that replaces the computationally expensive parts of the hydrodynamic models with simple and efficient data-driven approximations. Our hypothesis is that by integrating ML with physics-based numerical methods, we can achieve improved generalization performance: that is, the trained model for one case study can be used in other studies without the need for new training. We tested two ML approaches: for the first, we integrated curve fitting, and, for the second, artificial neural networks (ANN) with a finite volume scheme to solve the local inertial approximation of the SWEs. The data-driven models approximated the Momentum Equation, which explicitly solved the time derivative of flow rates. Water depths were then updated by applying a water balance equation. We also tested two different training datasets: the simulated dataset, generated from the results of hydrodynamic model, and the random dataset, generated by directly solving the momentum equation on randomly sampled input data. Various combinations of input features, for example, water slope and depth, were explored. The proposed models were trained in a small hypothetical case and tested in a different hypothetical and in two real case studies. Results showed that the curve-fitting method can be implemented successfully, given sufficient training and input data. The ANN model trained with a random dataset was substantially more accurate than that of the model trained with the simulated dataset. However, it was not successful in the real case studies. The curve-fitting method resulted in better generalization performance and increased the simulation speed of the local inertial model by 23%. Future research should test the performance of ML in terms of an increase in stable time step size and approximation of the full SWEs. 相似文献
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Recurrent climate‐induced mass mortality episodes have been recorded in the Mediterranean Sea over the past 15 years, affecting rocky benthic communities. In this study, we provide for the first time a report on the annual mortality events of benthic sessile invertebrates occurring in the eastern part of the Adriatic Sea. Over the course of 14 consecutive years, we studied the sea temperature gradient to a depth of 40 m and found an abnormal summer warming trend and an increased frequency of above‐average temperatures. Mortality events were recorded in the summers of 10 observed years, in particular in 2009, when the highest mortality rates were recorded. Late in summer 2009, extensive mass mortality of sessile invertebrates was observed in the entire Eastern Adriatic Sea. We performed an analysis of selected target benthic species associated with mass mortality events with inter‐regional differences in hydrological and temperature conditions. We were able to characterize the mortality event by studying five areas covering the northern, central and southern regions of the Eastern Adriatic Sea. The degree of impact on each study area was quantified at 28 sites by estimating the proportion of affected target species. According to the obtained data, the northern sites (Cres area) were the least affected, whereas sites in the Central and Southern Adriatic [Tela??ica and Lastovo Nature Parks, Mljet National Park (NP)] displayed the highest impact. In summer 2009, sea surface temperatures reached values of 28 °C in the Cres area and 30 °C in Mljet NP. These thermal conditions were concomitant with moderate to severe mass mortalities of benthic populations. Mass mortality events reached depths of 45 m in most parts of the affected areas. Amongst studied species, the scleractinian coral and gorgonian populations suffered the most extensive damage during the mass mortality events. 相似文献
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Maren Mohler Johannes Bühl Stephen Doherty Siegfried Eggl Vera Theresa Eybl François Farago Aleksandar Jaćimović Lars Hunger Nynne L. B. Lauritsen David Ludena Martina Meisnar Alexander Reissner Nicolas Sarda Benjamin Toullec Meritxell Viñas Tió 《Experimental Astronomy》2010,28(2-3):101-135
A high level of diversity has already been observed among the planets of our own Solar System. As such, one expects extrasolar planets to present a wide range of distinctive features, therefore the characterisation of Earth- and super Earth-like planets is becoming of key importance in scientific research. The Search (Spectropolarimetric Exoplanet AtmospheRe CHaracerisation) mission proposal of this paper represents one possible approach to realising these objectives. The mission goals of Search include the detailed characterisation of a wide variety of exoplanets, ranging from terrestrial planets to gas giants. More specifically, Search will determine atmospheric properties such as cloud coverage, surface pressure and atmospheric composition, and may also be capable of identifying basic surface features. To resolve a planet with a semi major axis of down to 1.4 AU and 30 pc distant Search will have a mirror system consisting of two segments, with elliptical rim, cut out of a parabolic mirror. This will yield an effective diameter of 9 m along one axis. A phase mask coronagraph along with an integral spectrograph will be used to overcome the contrast ratio of star to planet light. Such a mission would provide invaluable data on the diversity present in extrasolar planetary systems and much more could be learned from the similarities and differences compared to our own Solar System. This would allow our theories of planetary formation, atmospheric accretion and evolution to be tested, and our understanding of regions such as the outer limit of the Habitable Zone to be further improved. 相似文献
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李斌 《沙漠与绿洲气象(新疆气象)》2007,1(1):57-59
介绍了一个用多普勒或非多普勒雷达装备的新的自动化防雹雷达中心。该系统实现了从雷达采集云信息到发射装有催化剂火箭这一整个过程的自动化,从而提高了雷达中心的效能。系统包括雷达视频信号的数字化处理系统、天线控制子系统和专家信息系统。自动化防雹系统的应用范围广泛,例如:防雹作业,气象研究,降水测量和短期预报等。 相似文献
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The Rossby waves frequencies for all planets of the Solar system have been computed and compared with the frequencies of Rossby waves on the Earth. 相似文献
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Vesna Matović Suzana Erić Danica Srećković-Batoćanin Philippe Colomban Aleksandar Kremenović 《Environmental Earth Sciences》2014,72(6):1939-1951
Blocks of limestone and sandstone used in walls of the Manasija Monastery complex showed damage caused by the efflorescence and subflorescence of different salts in a low-pollution rural environment. In addition to common salts such as thenardite, thermonatrite, trona and gypsum, a small amount of eugsterite and darapskite was also present. Although these sodium and sodium–calcium salts formed where cement mortar was used for repairs, the lithological type and chemical composition of the substrate also had an influence on the development of distinct salts. The interaction between limestone and sandstone (substrates) and a solution rich in sodium (without calcium) was successfully simulated in the laboratory. The presence of gypsum and sodium–calcium sulphate, as experimental products, solely on the limestones indicated that, in addition to the cement-mortar solution, part of the calcium required for the formation of calcium and double sodium–calcium salts could occur from this substrate. 相似文献