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201.
Mehmet ?ahin B. Yi?it Y?ld?z Ozan ?enkal Vedat Pe?temalc? 《Journal of the Indian Society of Remote Sensing》2012,40(3):399-409
This study introduces artificial neural networks (ANNs) for the estimation of land surface temperature (LST) using meteorological and geographical data in Turkey (26?C45°E and 36?C42°N). A generalized regression neural network (GRNN) was used in the network. In order to train the neural network, meteorological and geographical data for the period from January 2002 to December 2002 for 10 stations (Adana, Afyon, Ankara, Eski?ehir, ?stanbul, ?zmir, Konya, Malatya, Rize, Sivas) spread over Turkey were used as training (six stations) and testing (four stations) data. Latitude, longitude, elevation and mean air temperature are used in the input layer of the network. Land surface temperature is the output. However, land surface temperature has been estimated as monthly mean by using NOAA-AVHRR satellite data in the thermal range over 10 stations in Turkey. The RMSE between the estimated and ground values for monthly mean with ANN temperature(LSTANN) and Becker and Li temperature(LSTB-L) method values have been found as 0.077?K and 0.091?K (training stations), 0.045?K and 0.003?K (testing stations), respectively. 相似文献
202.
Palma Orlović-Leko Zlatica Kozarac Božena Ćosović Slađana Strmečki Marta Plavšić 《Journal of Atmospheric Chemistry》2010,66(1-2):11-26
Characterization of atmospheric surfactants in bulk precipitations was carried out by adsorption study at the mercury electrode/solution interface using phase sensitive AC voltammetry. The structure and permeability of the adsorbed organic films at the mercury electrode was tested using the redox processes of lead and cadmium ions as electrochemical tools. The effects of organic matter from the bulk precipitations (rainwater and melted snow) were compared to those obtained for aqueous solutions of model substances: aromatic hydrocarbon (naphtalene), anionic surfactant (sodium dodecylbenzene sulfonate, NDBS), protein (albumine) and selected model substances suggested to be representative of water soluble organic compounds (WSOC) in atmospheric water (monocarboxylic, dicarboxylic, and polyacidic compounds and levoglucosan). It was found that substances like humic acid and 3-hydroxybutanoic acid may play an important role in atmospheric heterogeneous chemistry because of their surface active potential. 相似文献
203.
R. Dimitrova Jean-François Sini K. Richards M. Schatzmann M. Weeks E. Perez García C. Borrego 《Boundary-Layer Meteorology》2009,131(2):223-243
Micrometeorological conditions in the vicinity of urban buildings strongly influence the requirements that are imposed on
building heating and cooling. The goal of the present study, carried out within the Advance Tools for Rational Energy Use
towards Sustainability (ATREUS) European research network, is the evaluation of the wind field around buildings with walls
heated by solar radiation. Two computational fluid dynamics (CFD) codes were validated against extensive wind-tunnel observations
to assess the influence of thermal effects on model performance. The code selected from this validation was used to simulate
the wind and temperature fields for a summer day in a specific region of the city of Lisbon. For this study, the meteorological
data produced by a non-hydrostatic mesoscale atmospheric model (MM5) were used as boundary conditions for a CFD code, which
was further applied to analyze the effects of local roughness elements and thermodynamic conditions on the air flow around
buildings. The CFD modelling can also provide the inflow parameters for a Heating, Ventilation and Air Conditioning (HVAC)
system, used to evaluate the building energy budgets and to predict performance of the air-conditioning system. The main finding
of the present three-dimensional analyses is that thermal forcing associated with the heating of buildings can significantly
modify local properties of the air flow. 相似文献
204.
Size segregated sampling of aerosol particles at the coal-fired power station Šoštanj, Slovenia was performed by a newly developed
system. In addition, simultaneous sampling of particles was performed at two locations, Velenje and Veliki vrh, chosen on
the basis of long term monitoring of SO2 in the influential area of power plant. The signature of the power plant (e.g. characteristic size distributions of some
typical trace elements) was identified. For elements, like As, Mo, Cd and Ga, which are typical for coal combustion, the highest
concentrations were observed in the size range between 1 and 4 μm. For Se and sometimes for Ga two modes were identified,
first between 0.1 and 0.5 μm and second between 1 and 4 μm. Ratios between the average concentrations of selected elements
in fine and coarse particles collected at Veliki vrh (the most influenced location) and Velenje (usually not influenced by
the thermo power station) were significantly higher than 1 in the case of Mo and Se for coarse and fine size range, while
for As the ratio was higher than 1 for the coarse fraction. Consequently, Mo, Se and As were found as the most important tracers
for the emissions from the investigated source. On the basis of the ratios between the concentrations of elements measured
in particles at low and high SO2 concentrations at Veliki vrh, Cd was shown to be a typical tracer as well. Our results definitely showed that size segregated
measurements of particles at the source and in the influenced area give more precise information on the influence of source
to the surrounding region. It was found that patterns of size distributions for typical trace elements observed at the source
are found also in the influenced area, i.e. Veliki vrh. 相似文献
205.
H. Kiliç 《Solar physics》2009,255(1):155-162
The short-term periodicities in sunspot numbers, sunspot areas, and flare index data are investigated in detail using the
Date Compensated Discrete Fourier Transform (DCDFT) for the full disk of the Sun separately over the rising, the maximum,
and the declining portions of solar cycle 23 (1996 – 2006). While sunspot numbers and areas show several significant periodicities
in a wide range between 23.1 and 36.4 days, the flare index data do not exhibit any significant periodicity. The earlier conclusion
of Pap, Tobiska, and Bouwer (1990, Solar Phys.
129, 165) and Kane (2003, J. Atmos. Solar-Terr. Phys.
65, 1169), that the 27-day periodicity is more pronounced in the declining portion of a solar cycle than in the rising and maximum
ones, seems to be true for sunspot numbers and sunspot area data analyzed here during solar cycle 23. 相似文献
206.
This paper studies the relative orbital motion between arbitrary Keplerian trajectories. A closed-form vectorial solution
to the nonlinear initial value problem that models this type of motion with respect to a noninertial reference frame is offered.
Without imposing any particular conditions on the leader or the deputy satellites trajectories, exact expressions for the
relative law of motion and relative velocity are obtained in a closed form. This solution allows the parameterization of the
relative motion manifold and offers new methods to study its geometrical and topological properties. The result presented
in this paper opens the way to obtain new classes of approximate solutions to the equations of relative motion with time,
an eccentric or true anomaly as independent variables.
Published in Russian in Solar System Research, 2009, Vol. 43, No. 1, pp. 44–55.
The text was submitted by the autors in English. 相似文献
207.
In this study, heat waves at three meteorological stations in Serbia were analyzed based on the daily maximum temperature during the summer (June, July and August). The warmest summers as regards heat wave duration and severity occurred within the periods 1951–1952, 1987–1998 (especially 1994) and 2000–2007. The longest heat waves were recorded in 1952, lasting 16 days in Smederevska Palanka and 21 days in Ni?, while in 1994 in Belgrade lasting 18 days. The summer of 1994 in Belgrade and Smederevska Palanka, and 2003 in Ni? were characterized with the highest number of consecutive tropical days (21 and 29, respectively).The autoregressive-moving-average models were applied to generate long series of the daily maximum temperature, from which the relative frequencies of heat waves were estimated. The relationships between the longest heat waves, and the circulation conditions were analyzed using the subjective Hess–Brezowsky catalogue of weather types. 相似文献
208.
François Bétard 《地球表面变化过程与地形》2021,46(1):89-109
Insects are the largest and most diverse group of living organisms on Earth, playing a critical but underestimated role as agents of geomorphic change. Burrowing insects create micro-scale landforms such as subterranean tunnels and surface mounds and, by this way, exert an influence on hydrology, soil erosion and sediment transfer at a wider landscape scale. However, social insects represented by ants and termites were the main taxa studied as geomorphic agents and ecosystem engineers. This article proposes an extended and critical literature review of insects as zoogeomorphic agents, with reference to various taxonomic orders and families of insects having a burrowing behaviour. It provides a large overview of their primary and secondary impacts on Earth surface systems, both supported by naturalistic evidence and available quantitative data. Some evolutionary insights are discussed based on fossil evidence of geomorphic work by insects and, at finer temporal scale, on recent advances in radiometric and luminescence dating of insect mounds. Finally, this article explores the fruitful links between geomorphology and entomology, and suggests several research perspectives in order to develop an integrated understanding of the importance of insects in Earth surface processes and landforms. © 2020 John Wiley & Sons, Ltd. 相似文献
209.
Laurent REMUSAT Corentin Le GUILLOU Jean‐Noël ROUZAUD Laurent BINET Sylvie DERENNE François ROBERT 《Meteoritics & planetary science》2008,43(7):1099-1111
Abstract— Kainsaz CO3 insoluble organic matter (IOM) was studied using Curie point pyrolysis, electronic paramagnetic resonance (EPR), and high‐resolution transmission electron microscopy (HRTEM) to determine the effect of thermal metamorphism on molecular chondritic fingerprints. Pyrolysis released a very low amount of products that consist of one‐ and two‐ring aromatic units with methyl, dimethyl, and ethyl substituents. Moreover, Kainsaz IOM contains two orders of magnitude fewer radicals than Orgueil, Murchison, and Tagish Lake IOM. In addition, no diradicaloids were found in Kainsaz, although they are thought to constitute a specific signature for weakly organized extraterrestrial organic compounds in contrast to terrestrial ones. HRTEM reveals a very heterogeneous structure, with microporous disordered carbon, mesoporous graphitic carbons and graphite. Graphitization likely occurs and explains the differences between Kainsaz and CI or CM IOM. Heating stress experienced by Kainsaz IOM, on the parent body and/or prior its accretion, is likely responsible for the differences in molecular and structural organizations compared with those of CI and CM IOM. 相似文献
210.
Acta Geotechnica - A 3D multi-scale approach is presented to investigate the mechanical behavior of a macroscopic specimen consisting of a granular assembly, as a boundary value problem. The core... 相似文献