共查询到20条相似文献，搜索用时 953 毫秒
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Geomagnetism and Aeronomy - According to theoretical conclusions, zonal western thermospheric winds are the key influence on the generation of equatorial plasma “bubbles.” To verify... 相似文献
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D. G. Andrews 《地球物理与天体物理流体动力学》2013,107(3-4):330-332
Abstract By Susumu Kato. Center for Academic Publications Japan/D. Reidel Publishing Company, 1980. xiii+233pp. (£15.95) (ISBN 90277 1132 1). 相似文献
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M. Stix 《地球物理与天体物理流体动力学》2013,107(4):327-328
Abstract By E. R. Priest, Geophys. and Astrophys. Monographs, Vol. 21, D. Reidel, Dordrecht, 1982. xx + 469 pp, Dfl. 235, US $99.00 (ISBN 90-277-1374-x). 相似文献
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Ira Didenkulova Efim Pelinovsky Tarmo Soomere 《Pure and Applied Geophysics》2008,165(11-12):2249-2264
The problem of tsunami wave runup on a beach is discussed in the framework of the rigorous solutions of the nonlinear shallow-water theory. We present an analysis of the runup characteristics for various shapes of the incoming symmetrical solitary tsunami waves. It will be demonstrated that the extreme (maximal) wave characteristics on a beach (runup and draw-down heights, runup and draw-down velocities and breaking parameter) are weakly dependent on the shape of incident wave if the definition of the “significant” wavelength determined on the 2/3 level of the maximum height is used. The universal analytical expressions for the extreme wave characteristics are derived for the runup of the solitary pulses. They can be directly applicable for tsunami warning because in many cases the shape of the incident tsunami wave is unknown. 相似文献
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Ultracool stars usually have active regions, which is confirmed by their high-power radiofrequency emission modulated by the star axial rotation. The interpretation of this emission is commonly based on the electron cyclotron maser mechanism realized in the active regions. A plasma mechanism of radiofrequency emission is not considered, because ultracool star atmospheres are tightly “pressed” against the star surface, and the plasma frequency is much lower than the electron gyrofrequency (fL ? fB) at the coronal levels. This paper explores active regions of ultracool stars for the possible existence of a system of coronal magnetic loops carrying electric current generated by photospheric convection. It is shown that current dissipation induces a temperature increase inside the loops to about 107 K, which causes an increase in the scale of height of the inhomogeneous atmosphere and, at the coronal levels, effectuates condition fL ? fB, at which the plasma mechanism of radiofrequency emission prevails over the electron cyclotron maser mechanism. The magnetic loop parameters, intensity of electric currents generated by the photospheric convection, and efficiency of plasma heating inside the magnetic loops are evaluated on the example of the brown dwarf TVLM513-46546. The scale of the height of the modified atmosphere, which appears to be comparable to the star radius, is calculated; it is shown that the soft X-ray flow created by the hot modified atmosphere inside a coronal magnetic loop is about equal to that observed for brown dwarf TVLM513-46546. 相似文献
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Study of ozone “weekend effect” in Shanghai 总被引：6，自引：0，他引：6
WenYuan Tang ChunSheng Zhao FuHai Geng Li Peng GuangQiang Zhou Wei Gao JianMing Xu XueXi Tie 《中国科学D辑(英文版)》2008,51(9):1354-1360
Analysis of observed ozone data in 2006 from five monitoring sites (Xujiahui, Chongming, Baoshan, Pudong, Jinshan) in Shanghai reveals that ozone (O_3) concentrations in Xujiahui are higher at week-ends than those on weekdays, despite the fact that emissions of ozone precursor substances, such as oxides of nitrogen (NOx), carbon monoxide (CO) and volatile organic compounds (VOCs) are lower at weekends than those on weekdays. The possible chemical cause of ozone "weekend effect" is that NO_2/NO ratio increases at weekends by 25.61% compared with those on weekdays. In addition, because of an average 12.13% reduction in NOx (NO NO_2) in the early morning (05:00-09:00) at weekends compared with that on weekdays, the ozone inhibition period ends 0.5 h earlier at weekends resulting in the longer duration of ozone accumulation and the higher ozone production rate. The rate of ozone production is a function of VOCs and NOx in the atmosphere. VOCs/NOx ratio in Xujiahui is 4.55 at weekends, and 4.37 on weekdays, belonging to the "NOx-limited". The increasing VOCs/NOx ratio at weekends leads to ozone enhancement from 73 ppbv to 80 ppbv, which are consistent with ozone "weekend effect" in Xujiahui. Furthermore, combining with MICAPS cloud amount data, the fact that ozone "weekend effect" in Xujiahui weakens gradually along with the increasing of cloud amount indicates that ozone photochemical production leads to ozone "weekend effect" in Xujiahui of Shanghai. 相似文献
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The formation of bends (meanders) can be described by a simple physical model, according to which, water flow in a gentle valley with gentle slopes, once deflected by a random obstacle, starts oscillating from one slope to another, while keeping moving down the valley. The sinuosity of the river (the ratio of the path along its channel to the direct path along the valley) depends on the ratio of the steepness of the slopes and the valley; the mean sinuosity is close to 1.5 in accordance with the available geographic data. 相似文献
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The post-earthquake rapid accurate assessment of macro influence of seismic ground motion is of significance for earthquake emergency relief,post-earthquake reconstruction and scientific research. The seismic intensity distribution map released by the Lushan earthquake field team of the China Earthquake Administration(CEA) five days after the strong earthquake(M7.0) occurred in Lushan County of Sichuan Ya'an City at 8:02 on April 20,2013 provides a scientific basis for emergency relief,economic loss assessment and post-earthquake reconstruction. In this paper,the means for blind estimation of macroscopic intensity,field estimation of macro intensity,and review of intensity,as well as corresponding problems are discussed in detail,and the intensity distribution characteristics of the Lushan "4.20" M7.0 earthquake and its influential factors are analyzed,providing a reference for future seismic intensity assessments. 相似文献
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Applying the idea of renormalization group and fractal theory, we analyzed seismic hierarchy feature detailed. Based on the
seismogenic model of “fracture penetration”, we built a model of seismic critical instability, deduced its recursion relationship
of renormalization, and estimated the probability of its critical instability P.
The paper is supported by the Chinese Joint Seismological Science Foundation, Project No. 950085. 相似文献
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Citation Littlewood, I. G., Croke, B. F. W. & Young, P. C. (2011) Discussion of “Effects of temporal resolution on hydrological model parameters and its impact on prediction of river discharge” by Y. Wang, B. He & K. Takase (2009, Hydrol. Sci. J. 54(5), 886–898). Hydrol. Sci. J. 56(3), 521–524. 相似文献
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《Journal of Atmospheric and Solar》2002,64(15):1675-1677
Some additional data are given for the development of solar-terrestrial physics during the 19th and 20th centuries. 相似文献
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Marine magnetic anomalies of the tiny wiggles (TW) type can be used to solve geohistorical and paleomagnetic problems. The model fields corresponding to Paleocene–Eocene anomalies in the northwestern Indian Ocean, which were formed during the fast-spreading stage, were studied. For these fields, widely used interpretation methods were compared with a method proposed previously by the authors. The testing was performed with first the classical block model and then more complex models reflecting actual processes of oceanic accretion and magnetic field variations in the past. It was shown that the proposed method has advantages for this problem; it gives an error close to the minimum possible error and can adequately be used in interpretations. Spectral and statistical methods are used to estimate the magnetic anomaly resolving power and to study some factors that can exert a distorting influence. In addition, model examples have been used to indicate how the TW determination accuracy is affected by diurnal variations in the main magnetic field (MMF) and by ancient magnetization vector determination errors. 相似文献
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George P L Walker 《Bulletin of Volcanology》1991,53(7):546-558
Tumuli are positive topographic features that are common on Hawaiian pahoehoe lava flow fields, particularly on shallow slopes, and 75 measured examples are presented here to document the size range. Tumuli form by up-tilting of crustal plates, without any crustal shortening, and are thus distinguished from pressure ridges which are up-buckled by laterally directed pressure. The axial or star-like systems of deep clefts that characterize tumuli are defined here as lava-inflation clefts; their tips advanced into red-hot lava and they widened as uplift proceeded and while the lava crust was thickening. Flat-surfaced uplifts, formed like tumuli by injection of lava under a surface crust, were previously called pressure plateaus, but lava rise is proposed instead. The pits that abound among lava rises, previously attributed to collapse or subsidence, are generally formed because the lava around them rose, and the name lava-rise pit is proposed. Unique examples of tumuli and lava rises, from which lava drained out under a surface crust 1.5 to 2.5 m thick, are described from Kilauea caldera. These examples show that in tumuli and lava rises the crust floats on considerable bodies of fluid lava, and is able to do so because of its higher vesicle content: the fluid lava loses many of its gas bubbles during residence beneath the crust. The bulk densities of samples from tumuli show a general downward increase. The form of the density profile is consistent with the relationship that for any given crustal thickness the density of fluid lava closely matched the average density of that crust, suggesting that the lava was stably density-stratified. It is inferred that stable stratification was regulated by out-flows of the more vesicular lava fractions, loss of bubbles through the lava-inflation clefts, and entry of injected lava at its level of neutral buoyancy. Below the uppermost meter the downward decrease in vesicularity closely conforms with that expected by compression of a uniform mass of gas per unit mass of lava. 相似文献
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Construction algorithms of the expert system are given. The results of expert system application to the assessment of the trophic status of Karelian lakes are presented. The system was tested against independent data on well-known lakes. The lakes were classified with the use of fuzzy logic apparatus. 相似文献